diff --git a/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/BaseNpmPackageLoaderInMemory.java b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/BaseNpmPackageLoaderInMemory.java
new file mode 100644
index 0000000000..ed4892ffae
--- /dev/null
+++ b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/BaseNpmPackageLoaderInMemory.java
@@ -0,0 +1,166 @@
+package org.opencds.cqf.fhir.utility.npm;
+
+import ca.uhn.fhir.context.FhirContext;
+import ca.uhn.fhir.context.FhirVersionEnum;
+import ca.uhn.fhir.rest.server.exceptions.InternalErrorException;
+import ca.uhn.fhir.rest.server.exceptions.InvalidRequestException;
+import jakarta.annotation.Nonnull;
+import jakarta.annotation.Nullable;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.StringJoiner;
+import java.util.stream.Collectors;
+import org.hl7.cql.model.NamespaceInfo;
+import org.hl7.fhir.instance.model.api.IBaseResource;
+import org.hl7.fhir.instance.model.api.IPrimitiveType;
+import org.hl7.fhir.utilities.npm.NpmPackage;
+
+public abstract class BaseNpmPackageLoaderInMemory implements NpmPackageLoader {
+
+    public static final String FAILED_TO_LOAD_RESOURCE_TEMPLATE = "Failed to load resource: %s";
+
+    private final Set<NpmPackage> npmPackages;
+    private final NpmNamespaceManager npmNamespaceManager;
+
+    @Override
+    public Optional<IBaseResource> loadNpmResource(IPrimitiveType<String> resourceUrl) {
+        return npmPackages.stream()
+                .filter(npmPackage -> doesPackageMatch(resourceUrl, npmPackage))
+                .map(npmPackage -> getResource(npmPackage, resourceUrl))
+                .findFirst();
+    }
+
+    private IBaseResource getResource(NpmPackage npmPackage, IPrimitiveType<String> resourceUrl) {
+        try {
+            return tryGetResource(npmPackage, resourceUrl);
+        } catch (IOException exception) {
+            throw new InternalErrorException(
+                    FAILED_TO_LOAD_RESOURCE_TEMPLATE.formatted(resourceUrl.getValue()), exception);
+        }
+    }
+
+    private IBaseResource tryGetResource(NpmPackage npmPackage, IPrimitiveType<String> resourceUrl) throws IOException {
+
+        final FhirContext fhirContext = getFhirContext(npmPackage);
+        final String resourceUrlString = resourceUrl.getValue();
+
+        final String[] split = resourceUrlString.split("\\|");
+
+        try (InputStream libraryInputStream = npmPackage.loadByCanonical(split[0])) {
+            return fhirContext.newJsonParser().parseResource(libraryInputStream);
+        }
+    }
+
+    private boolean doesPackageMatch(IPrimitiveType<String> resourceUrl, NpmPackage npmPackage) {
+        try {
+            return npmPackage.hasCanonical(resourceUrl.getValue());
+        } catch (IOException exception) {
+            throw new InternalErrorException(FAILED_TO_LOAD_RESOURCE_TEMPLATE, exception);
+        }
+    }
+
+    @Override
+    public NpmNamespaceManager getNamespaceManager() {
+        return npmNamespaceManager;
+    }
+
+    @Nonnull
+    protected static Set<NpmPackage> buildNpmPackagesFromAbsolutePath(List<Path> tgzPaths) {
+        return tgzPaths.stream()
+                .map(BaseNpmPackageLoaderInMemory::getNpmPackageFromAbsolutePaths)
+                .collect(Collectors.toUnmodifiableSet());
+    }
+
+    @Nonnull
+    protected static Set<NpmPackage> buildNpmPackageFromClasspath(Class<?> clazz, List<Path> tgzPaths) {
+        return tgzPaths.stream()
+                .map(path -> getNpmPackageFromClasspath(clazz, path))
+                .collect(Collectors.toUnmodifiableSet());
+    }
+
+    @Nonnull
+    private static NpmPackage getNpmPackageFromAbsolutePaths(Path tgzPath) {
+        try (final InputStream npmStream = Files.newInputStream(tgzPath)) {
+            return NpmPackage.fromPackage(npmStream);
+        } catch (IOException exception) {
+            throw new InvalidRequestException(FAILED_TO_LOAD_RESOURCE_TEMPLATE.formatted(tgzPath), exception);
+        }
+    }
+
+    @Nonnull
+    private static NpmPackage getNpmPackageFromClasspath(Class<?> clazz, Path tgzClasspathPath) {
+        try (final InputStream simpleAlphaStream = clazz.getResourceAsStream(tgzClasspathPath.toString())) {
+            if (simpleAlphaStream == null) {
+                throw new InvalidRequestException(FAILED_TO_LOAD_RESOURCE_TEMPLATE.formatted(tgzClasspathPath));
+            }
+
+            return NpmPackage.fromPackage(simpleAlphaStream);
+        } catch (IOException exception) {
+            throw new InvalidRequestException(FAILED_TO_LOAD_RESOURCE_TEMPLATE.formatted(tgzClasspathPath), exception);
+        }
+    }
+
+    protected BaseNpmPackageLoaderInMemory(
+            Set<NpmPackage> npmPackages, @Nullable NpmNamespaceManager npmNamespaceManager) {
+
+        if (npmNamespaceManager == null) {
+            var namespaceInfos = npmPackages.stream()
+                    .map(npmPackage -> new NamespaceInfo(npmPackage.name(), npmPackage.canonical()))
+                    .toList();
+
+            this.npmNamespaceManager = new NpmNamespaceManagerFromList(namespaceInfos);
+        } else {
+            this.npmNamespaceManager = npmNamespaceManager;
+        }
+
+        this.npmPackages = npmPackages;
+    }
+
+    private FhirContext getFhirContext(NpmPackage npmPackage) {
+        return FhirContext.forCached(FhirVersionEnum.forVersionString(npmPackage.fhirVersion()));
+    }
+
+    /**
+     * Meant to test various scenarios involving missing of faulty NamespaceInfo data.
+     */
+    public static class NpmNamespaceManagerFromList implements NpmNamespaceManager {
+
+        private final List<NamespaceInfo> namespaceInfos;
+
+        public NpmNamespaceManagerFromList(List<NamespaceInfo> namespaceInfos) {
+            this.namespaceInfos = List.copyOf(namespaceInfos);
+        }
+
+        @Override
+        public List<NamespaceInfo> getAllNamespaceInfos() {
+            return namespaceInfos;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            NpmNamespaceManagerFromList that = (NpmNamespaceManagerFromList) o;
+            return Objects.equals(namespaceInfos, that.namespaceInfos);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(namespaceInfos);
+        }
+
+        @Override
+        public String toString() {
+            return new StringJoiner(", ", NpmNamespaceManagerFromList.class.getSimpleName() + "[", "]")
+                    .add("namespaceInfos=" + namespaceInfos)
+                    .toString();
+        }
+    }
+}
diff --git a/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmConfigDependencySubstitutor.java b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmConfigDependencySubstitutor.java
new file mode 100644
index 0000000000..b7197d46aa
--- /dev/null
+++ b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmConfigDependencySubstitutor.java
@@ -0,0 +1,24 @@
+package org.opencds.cqf.fhir.utility.npm;
+
+import java.util.Optional;
+
+/**
+ * This class is meant to be used from Spring configuration classes, in the case of any missing
+ * NpmPackageLoader bean definitions, which Spring will inject as empty Optionals.
+ * <p/>
+ * Helps implement a migration from the old world of FHIR/Repository based resources for Libraries,
+ * Measures and eventually other clinical intelligence resources (such as PlanDefinitions or
+ * ValueSets), and the new world where they're derived from NPM packages.
+ * If Spring config is missing an instance of {@link NpmPackageLoader}, then * return the default
+ * instance.
+ */
+public class NpmConfigDependencySubstitutor {
+
+    private NpmConfigDependencySubstitutor() {
+        // static utility class
+    }
+
+    public static NpmPackageLoader substituteNpmPackageLoaderIfEmpty(Optional<NpmPackageLoader> optNpmPackageLoader) {
+        return NpmPackageLoader.getDefaultIfEmpty(optNpmPackageLoader.orElse(null));
+    }
+}
diff --git a/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmNamespaceManager.java b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmNamespaceManager.java
new file mode 100644
index 0000000000..c983a2d076
--- /dev/null
+++ b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmNamespaceManager.java
@@ -0,0 +1,16 @@
+package org.opencds.cqf.fhir.utility.npm;
+
+import java.util.List;
+import org.hl7.cql.model.NamespaceInfo;
+
+/**
+ * Load all {@link NamespaceInfo}s capturing package ID to URL mappings associated with the NPM
+ * packages maintained for clinical-reasoning NPM package users to be used to resolve cross-package
+ * Library/CQL dependencies.  See {@link NpmPackageLoader}.
+ */
+public interface NpmNamespaceManager {
+
+    NpmNamespaceManager DEFAULT = List::of;
+
+    List<NamespaceInfo> getAllNamespaceInfos();
+}
diff --git a/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmPackageLoader.java b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmPackageLoader.java
new file mode 100644
index 0000000000..87dadd7b0f
--- /dev/null
+++ b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/NpmPackageLoader.java
@@ -0,0 +1,308 @@
+package org.opencds.cqf.fhir.utility.npm;
+
+import ca.uhn.fhir.context.FhirContext;
+import ca.uhn.fhir.context.FhirVersionEnum;
+import ca.uhn.fhir.repository.IRepository;
+import ca.uhn.fhir.rest.server.exceptions.InvalidRequestException;
+import jakarta.annotation.Nullable;
+import java.util.List;
+import java.util.Optional;
+import org.cqframework.cql.cql2elm.LibraryManager;
+import org.cqframework.cql.cql2elm.LibrarySourceProvider;
+import org.hl7.cql.model.ModelIdentifier;
+import org.hl7.cql.model.NamespaceInfo;
+import org.hl7.cql.model.NamespaceManager;
+import org.hl7.elm.r1.VersionedIdentifier;
+import org.hl7.fhir.instance.model.api.IBaseResource;
+import org.hl7.fhir.instance.model.api.IPrimitiveType;
+import org.opencds.cqf.fhir.utility.adapter.IAdapterFactory;
+import org.opencds.cqf.fhir.utility.adapter.ILibraryAdapter;
+import org.opencds.cqf.fhir.utility.adapter.IResourceAdapter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * FHIR version agnostic Interface for loading NPM resources including Measures, Libraries and
+ * potentially other qualifying resources.
+ * <p/>
+ * This javadoc documents the entire NPM package feature in the clinical-reasoning project.  Please
+ * read below:
+ * <p/>
+ * A downstream app from clinical-reasoning will be able to maintain Measures and Libraries loaded
+ * from NPM packages.  Such Measures and Libraries will, for those clients implementing this
+ * feature, no longer be maintained in {@link IRepository} storage, unlike all other FHIR resources,
+ * such as Patients.
+ * <p/>
+ * Downstream apps are responsible for loading and retrieving such packages from implementations
+ * of the below interface.  Additionally, they must map all package IDs to package URLs via a
+ * List of {@link NamespaceInfo}s.  This is done via the
+ * {@link #initNamespaceMappings(LibraryManager)}, as due to how CQL libraries are loaded, it
+ * won't work automatically.
+ * <p/>
+ * When CQL runs and calls a custom {@link LibrarySourceProvider}, it will query all NPM packages
+ * accessible by the backing implementation.
+ * <p/>
+ * The above should also work with multiple layers of includes across packages.
+ * <p/>
+ * This workflow is meant to be triggered by a new Measure operation provider:
+ * $evaluate-measure-by-url, which takes a canonical measure URL instead of a measure ID like
+ * $evaluate-measure.
+ * <p/>
+ * Example:  Package with ID X and URL <a href='http://packageX.org'>...</a> contains Measure ABC
+ * is associated with Library 123, which contains CQL that includes Library 456 from NPM Package
+ * with ID Y  and URL <a href='http://packageX.org'>...</a>, which contains both the Library and
+ * its CQL.  When resolve the CQL include pointing to Package ID Y, the CQL engine must be able
+ * to read the namespace info and resolve ID Y to URL <a href='http://packageY.org'>...</a>.  This
+ * can only be accomplished via an explicit mapping.
+ * <p/>
+ * Note that, depending on the implementation, there is the real possibility of Measures
+ * corresponding to the same canonical URL among multiple NPM packages.  As such, clients who
+ * unintentionally add Measures with the same URL in at least two different packages may see the
+ * Measure they're not expecting during an $evaluate-measure-by-url, and may file production
+ * issues accordingly.
+ */
+public interface NpmPackageLoader {
+    Logger logger = LoggerFactory.getLogger(NpmPackageLoader.class);
+
+    String LIBRARY_URL_TEMPLATE = "%s/Library/%s";
+    String LIBRARY = "Library";
+    String MEASURE = "Measure";
+
+    // effectively a no-op implementation
+    NpmPackageLoader R4_DEFAULT = new NpmPackageLoader() {
+
+        @Override
+        public Optional<IBaseResource> loadNpmResource(IPrimitiveType<String> canonicalUrl) {
+            return Optional.empty();
+        }
+
+        @Override
+        public NpmNamespaceManager getNamespaceManager() {
+            return NpmNamespaceManager.DEFAULT;
+        }
+
+        @Override
+        public FhirContext getFhirContext() {
+            return FhirContext.forR4Cached();
+        }
+    };
+
+    /**
+     * Query the NPM package repo for the resource corresponding to the provided resource class and
+     * canonical URL corresponding to the NPM package repo.
+     *
+     * @param resourceClass        The expected class of the resource to be returned, which will
+     *                             be checked via instanceof before being cast and returned.
+     * @param canonicalResourceUrl The resource URL provided by the caller, corresponding to a
+     *                             resource contained within one of the stored NPM packages.
+     * @return The resource (any {@link IBaseResource}) corresponding to the URL.
+     */
+    default <T extends IBaseResource> Optional<T> loadNpmResource(
+            Class<T> resourceClass, IPrimitiveType<String> canonicalResourceUrl) {
+
+        final Optional<? extends IBaseResource> optResource = loadNpmResource(canonicalResourceUrl);
+
+        if (optResource.isEmpty()) {
+            return Optional.empty();
+        }
+
+        final IBaseResource resource = optResource.get();
+
+        if (!resourceClass.isInstance(resource)) {
+            throw new IllegalArgumentException("Expected resource to be a %s, but was a %s"
+                    .formatted(resourceClass.getSimpleName(), resource.fhirType()));
+        }
+
+        return Optional.of(resourceClass.cast(resource));
+    }
+
+    default IAdapterFactory getAdapterFactory() {
+        return IAdapterFactory.forFhirVersion(getFhirContext().getVersion().getVersion());
+    }
+
+    /**
+     * Obtain the resource corresponding to the provided type-enclosed String URL from the NPM
+     * package repo.  Implementors must figure out how to retrieve the resource by querying one
+     * or more NPM packages maintained by the application.
+     *
+     * @param canonicalResourceUrl The type-enclosed String canonical URL of the resource to load.
+     * @return The resource corresponding to the URL, if it exists.
+     */
+    Optional<IBaseResource> loadNpmResource(IPrimitiveType<String> canonicalResourceUrl);
+
+    /**
+     * Implementors must commit to supporting a specific FHIR version, in order to ensure that
+     * the correct version of a given resource is used for both the FHIR canonical URL and the
+     * returned resource.
+     *
+     * @return The FhirContext corresponding to the FHIR version of the NPM packages maintained
+     * by the application.
+     */
+    FhirContext getFhirContext();
+
+    /**
+     * It's up to implementors to maintain the NamespaceManager that maintains the NamespaceInfos.
+     */
+    NpmNamespaceManager getNamespaceManager();
+
+    /**
+     * Hackish:  Either the downstream app injected this or we default to a NO-OP implementation.
+     *
+     * @param npmPackageLoader The NpmPackageLoader, if injected by the downstream app,
+     *                           otherwise null.
+     * @return Either the downstream app's NpmPackageLoader a no-op implementation.
+     */
+    static NpmPackageLoader getDefaultIfEmpty(@Nullable NpmPackageLoader npmPackageLoader) {
+        return Optional.ofNullable(npmPackageLoader).orElse(NpmPackageLoader.R4_DEFAULT);
+    }
+
+    /**
+     * Ensure the passed Library gets initialized with the NPM namespace mappings belonging
+     * to this instance of NpmPackageLoader.
+     *
+     * @param libraryManager from the CQL Engine being used for an evaluation
+     */
+    default void initNamespaceMappings(LibraryManager libraryManager) {
+        final List<NamespaceInfo> allNamespaceInfos = getAllNamespaceInfos();
+        final NamespaceManager namespaceManager = libraryManager.getNamespaceManager();
+
+        for (NamespaceInfo namespaceInfo : allNamespaceInfos) {
+            // if we do this more than one time it won't error out subsequent times
+            namespaceManager.ensureNamespaceRegistered(namespaceInfo);
+        }
+    }
+
+    /**
+     * @return All NamespaceInfos to map package IDs to package URLs for all NPM Packages maintained
+     * for clinical-reasoning NPM package to be used to resolve cross-package Library/CQL
+     * dependencies.
+     */
+    default List<NamespaceInfo> getAllNamespaceInfos() {
+        return getNamespaceManager().getAllNamespaceInfos();
+    }
+
+    default Optional<ILibraryAdapter> findMatchingLibrary(VersionedIdentifier versionedIdentifier) {
+        return findLibraryFromUnrelatedNpmPackage(versionedIdentifier);
+    }
+
+    default Optional<ILibraryAdapter> findMatchingLibrary(ModelIdentifier modelIdentifier) {
+        return findLibraryFromUnrelatedNpmPackage(modelIdentifier);
+    }
+
+    default Optional<ILibraryAdapter> findLibraryFromUnrelatedNpmPackage(VersionedIdentifier versionedIdentifier) {
+        return loadLibraryByUrl(getUrl(versionedIdentifier));
+    }
+
+    default Optional<ILibraryAdapter> findLibraryFromUnrelatedNpmPackage(ModelIdentifier modelIdentifier) {
+        return loadLibraryByUrl(getUrl(modelIdentifier));
+    }
+
+    /**
+     * @param libraryUrl The Library URL converted from a given
+     *                   withing one of the stored NPM packages.
+     * @return The Measure corresponding to the URL.
+     */
+    default Optional<ILibraryAdapter> loadLibraryByUrl(String libraryUrl) {
+
+        return toLibraryAdapter(
+                loadNpmResource(getLibraryClass(), toPrimitiveType(libraryUrl)).orElse(null));
+    }
+
+    default Optional<ILibraryAdapter> toLibraryAdapter(IBaseResource resource) {
+        if (resource == null) {
+            return Optional.empty();
+        }
+        switch (getFhirContext().getVersion().getVersion()) {
+            case R4 -> {
+                if (!(resource instanceof org.hl7.fhir.r4.model.Library r4Library)) {
+                    throw new IllegalArgumentException(
+                            "Expected resource to be a Library, but was a " + resource.fhirType());
+                }
+                return Optional.of(new org.opencds.cqf.fhir.utility.adapter.r4.LibraryAdapter(r4Library));
+            }
+            case R5 -> {
+                if (!(resource instanceof org.hl7.fhir.r5.model.Library r5Library)) {
+                    throw new IllegalArgumentException(
+                            "Expected resource to be a Library, but was a " + resource.fhirType());
+                }
+                return Optional.of(new org.opencds.cqf.fhir.utility.adapter.r5.LibraryAdapter(r5Library));
+            }
+            default -> throw new IllegalStateException(
+                    "Unsupported FHIR version: " + getFhirContext().getVersion().getVersion());
+        }
+    }
+
+    default IPrimitiveType<String> toPrimitiveType(String libraryUrl) {
+        switch (getFhirContext().getVersion().getVersion()) {
+            case R4 -> {
+                return new org.hl7.fhir.r4.model.StringType(libraryUrl);
+            }
+            case R5 -> {
+                return new org.hl7.fhir.r5.model.StringType(libraryUrl);
+            }
+            default -> throw new IllegalStateException(
+                    "Unsupported FHIR version: " + getFhirContext().getVersion().getVersion());
+        }
+    }
+
+    default Class<? extends IBaseResource> getLibraryClass() {
+        switch (getFhirContext().getVersion().getVersion()) {
+            case R4 -> {
+                return org.hl7.fhir.r4.model.Library.class;
+            }
+            case R5 -> {
+                return org.hl7.fhir.r5.model.Library.class;
+            }
+            default -> throw new IllegalStateException(
+                    "Unsupported FHIR version: " + getFhirContext().getVersion().getVersion());
+        }
+    }
+
+    default IResourceAdapter toResourceAdapter(IBaseResource resource) {
+        if (resource == null) {
+            return null;
+        }
+        if (FhirVersionEnum.R4 == getFhirContext().getVersion().getVersion()) {
+            switch (resource.fhirType()) {
+                case LIBRARY -> {
+                    return new org.opencds.cqf.fhir.utility.adapter.r4.LibraryAdapter(
+                            (org.hl7.fhir.r4.model.Library) resource);
+                }
+                case MEASURE -> {
+                    return new org.opencds.cqf.fhir.utility.adapter.r4.MeasureAdapter(
+                            (org.hl7.fhir.r4.model.Measure) resource);
+                }
+                default -> throw new IllegalArgumentException(
+                        "Expected resource to be a Library or Measure, but was a " + resource.fhirType());
+            }
+        }
+
+        if (FhirVersionEnum.R5 == getFhirContext().getVersion().getVersion()) {
+            switch (resource.fhirType()) {
+                case LIBRARY -> {
+                    return new org.opencds.cqf.fhir.utility.adapter.r5.LibraryAdapter(
+                            (org.hl7.fhir.r5.model.Library) resource);
+                }
+                case MEASURE -> {
+                    return new org.opencds.cqf.fhir.utility.adapter.r5.MeasureAdapter(
+                            (org.hl7.fhir.r5.model.Measure) resource);
+                }
+                default -> throw new IllegalArgumentException(
+                        "Expected resource to be a Library or Measure, but was a " + resource.fhirType());
+            }
+        }
+
+        throw new InvalidRequestException("Unsupported FHIR version: %s"
+                .formatted(getFhirContext().getVersion().getVersion().toString()));
+    }
+
+    private String getUrl(VersionedIdentifier versionedIdentifier) {
+        // We need this case because the CQL engine will do the right thing and populate the system
+        // in the cross-package target case
+        return LIBRARY_URL_TEMPLATE.formatted(versionedIdentifier.getSystem(), versionedIdentifier.getId());
+    }
+
+    private String getUrl(ModelIdentifier modelIdentifier) {
+        return LIBRARY_URL_TEMPLATE.formatted(modelIdentifier.getSystem(), modelIdentifier.getId());
+    }
+}
diff --git a/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/r4/R4NpmPackageLoaderInMemory.java b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/r4/R4NpmPackageLoaderInMemory.java
new file mode 100644
index 0000000000..bea2e32903
--- /dev/null
+++ b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/r4/R4NpmPackageLoaderInMemory.java
@@ -0,0 +1,65 @@
+package org.opencds.cqf.fhir.utility.npm.r4;
+
+import ca.uhn.fhir.context.FhirContext;
+import jakarta.annotation.Nullable;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+import org.hl7.fhir.utilities.npm.NpmPackage;
+import org.opencds.cqf.fhir.utility.npm.BaseNpmPackageLoaderInMemory;
+import org.opencds.cqf.fhir.utility.npm.NpmNamespaceManager;
+import org.opencds.cqf.fhir.utility.npm.NpmPackageLoader;
+
+/**
+ * Simplistic implementation of {@link NpmPackageLoader} that loads NpmPackages from the classpath
+ * and stores {@link NpmPackage}s in a Set. This class is recommended for testing
+ * and NOT for production.
+ * <p/>
+ * Optionally uses a custom {@link NpmNamespaceManager} but can also resolve all NamespaceInfos
+ * by extracting them from all loaded packages at construction time.
+ * <p/>
+ * This is for R4 only.
+ */
+public class R4NpmPackageLoaderInMemory extends BaseNpmPackageLoaderInMemory implements NpmPackageLoader {
+
+    public static R4NpmPackageLoaderInMemory fromNpmPackageAbsolutePath(List<Path> tgzPaths) {
+        return fromNpmPackageAbsolutePath(null, tgzPaths);
+    }
+
+    public static R4NpmPackageLoaderInMemory fromNpmPackageAbsolutePath(
+            NpmNamespaceManager npmNamespaceManager, List<Path> tgzPaths) {
+        final Set<NpmPackage> npmPackages = buildNpmPackagesFromAbsolutePath(tgzPaths);
+
+        return new R4NpmPackageLoaderInMemory(npmPackages, npmNamespaceManager);
+    }
+
+    public static R4NpmPackageLoaderInMemory fromNpmPackageClasspath(Class<?> clazz, Path... tgzPaths) {
+        return fromNpmPackageClasspath(null, clazz, tgzPaths);
+    }
+
+    public static R4NpmPackageLoaderInMemory fromNpmPackageClasspath(
+            @Nullable NpmNamespaceManager npmNamespaceManager, Class<?> clazz, Path... tgzPaths) {
+        return fromNpmPackageClasspath(npmNamespaceManager, clazz, Arrays.asList(tgzPaths));
+    }
+
+    public static R4NpmPackageLoaderInMemory fromNpmPackageClasspath(Class<?> clazz, List<Path> tgzPaths) {
+        return fromNpmPackageClasspath(null, clazz, tgzPaths);
+    }
+
+    public static R4NpmPackageLoaderInMemory fromNpmPackageClasspath(
+            @Nullable NpmNamespaceManager npmNamespaceManager, Class<?> clazz, List<Path> tgzPaths) {
+        final Set<NpmPackage> npmPackages = buildNpmPackageFromClasspath(clazz, tgzPaths);
+
+        return new R4NpmPackageLoaderInMemory(npmPackages, npmNamespaceManager);
+    }
+
+    public R4NpmPackageLoaderInMemory(Set<NpmPackage> npmPackages, @Nullable NpmNamespaceManager npmNamespaceManager) {
+        super(npmPackages, npmNamespaceManager);
+    }
+
+    @Override
+    public FhirContext getFhirContext() {
+        return FhirContext.forR4Cached();
+    }
+}
diff --git a/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/r5/R5NpmPackageLoaderInMemory.java b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/r5/R5NpmPackageLoaderInMemory.java
new file mode 100644
index 0000000000..801e67eb94
--- /dev/null
+++ b/cqf-fhir-utility/src/main/java/org/opencds/cqf/fhir/utility/npm/r5/R5NpmPackageLoaderInMemory.java
@@ -0,0 +1,65 @@
+package org.opencds.cqf.fhir.utility.npm.r5;
+
+import ca.uhn.fhir.context.FhirContext;
+import jakarta.annotation.Nullable;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+import org.hl7.fhir.utilities.npm.NpmPackage;
+import org.opencds.cqf.fhir.utility.npm.BaseNpmPackageLoaderInMemory;
+import org.opencds.cqf.fhir.utility.npm.NpmNamespaceManager;
+import org.opencds.cqf.fhir.utility.npm.NpmPackageLoader;
+
+/**
+ * Simplistic implementation of {@link NpmPackageLoader} that loads NpmPackages from the classpath
+ * and stores {@link NpmPackage}s in a Set. This class is recommended for testing
+ * and NOT for production.
+ * <p/>
+ * Optionally uses a custom {@link NpmNamespaceManager} but can also resolve all NamespaceInfos
+ * by extracting them from all loaded packages at construction time.
+ * <p/>
+ * This is for R5 only.
+ */
+public class R5NpmPackageLoaderInMemory extends BaseNpmPackageLoaderInMemory implements NpmPackageLoader {
+
+    public static R5NpmPackageLoaderInMemory fromNpmPackageAbsolutePath(List<Path> tgzPaths) {
+        return fromNpmPackageAbsolutePath(null, tgzPaths);
+    }
+
+    public static R5NpmPackageLoaderInMemory fromNpmPackageAbsolutePath(
+            NpmNamespaceManager npmNamespaceManager, List<Path> tgzPaths) {
+        final Set<NpmPackage> npmPackages = buildNpmPackagesFromAbsolutePath(tgzPaths);
+
+        return new R5NpmPackageLoaderInMemory(npmPackages, npmNamespaceManager);
+    }
+
+    public static R5NpmPackageLoaderInMemory fromNpmPackageClasspath(Class<?> clazz, Path... tgzPaths) {
+        return fromNpmPackageClasspath(null, clazz, tgzPaths);
+    }
+
+    public static R5NpmPackageLoaderInMemory fromNpmPackageClasspath(
+            @Nullable NpmNamespaceManager npmNamespaceManager, Class<?> clazz, Path... tgzPaths) {
+        return fromNpmPackageClasspath(npmNamespaceManager, clazz, Arrays.asList(tgzPaths));
+    }
+
+    public static R5NpmPackageLoaderInMemory fromNpmPackageClasspath(Class<?> clazz, List<Path> tgzPaths) {
+        return fromNpmPackageClasspath(null, clazz, tgzPaths);
+    }
+
+    public static R5NpmPackageLoaderInMemory fromNpmPackageClasspath(
+            @Nullable NpmNamespaceManager npmNamespaceManager, Class<?> clazz, List<Path> tgzPaths) {
+        final Set<NpmPackage> npmPackages = buildNpmPackageFromClasspath(clazz, tgzPaths);
+
+        return new R5NpmPackageLoaderInMemory(npmPackages, npmNamespaceManager);
+    }
+
+    public R5NpmPackageLoaderInMemory(Set<NpmPackage> npmPackages, @Nullable NpmNamespaceManager npmNamespaceManager) {
+        super(npmPackages, npmNamespaceManager);
+    }
+
+    @Override
+    public FhirContext getFhirContext() {
+        return FhirContext.forR5Cached();
+    }
+}
diff --git a/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/BaseNpmPackageLoaderTest.java b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/BaseNpmPackageLoaderTest.java
new file mode 100644
index 0000000000..c57af47cd5
--- /dev/null
+++ b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/BaseNpmPackageLoaderTest.java
@@ -0,0 +1,124 @@
+package org.opencds.cqf.fhir.utility.npm;
+
+import jakarta.annotation.Nonnull;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+
+public abstract class BaseNpmPackageLoaderTest {
+
+    protected static final String DOT_TGZ = ".tgz";
+
+    protected static final String SIMPLE_ALPHA_LOWER = "simplealpha";
+    protected static final String SIMPLE_ALPHA_MIXED = "SimpleAlpha";
+    protected static final String SIMPLE_BRAVO_LOWER = "simplebravo";
+    protected static final String SIMPLE_BRAVO_MIXED = "SimpleBravo";
+    protected static final String WITH_DERIVED_LIBRARY_LOWER = "withderivedlibrary";
+    protected static final String WITH_DERIVED_LIBRARY_MIXED = "WithDerivedLibrary";
+    protected static final String DERIVED_LIBRARY_ID = "DerivedLibrary";
+    protected static final String DERIVED_LIBRARY = DERIVED_LIBRARY_ID;
+
+    protected static final String DERIVED_LAYER_1_A = "DerivedLayer1a";
+    protected static final String DERIVED_LAYER_1_B = "DerivedLayer1b";
+    protected static final String DERIVED_LAYER_2_A = "DerivedLayer2a";
+    protected static final String DERIVED_LAYER_2_B = "DerivedLayer2b";
+    protected static final String CROSS_PACKAGE_SOURCE = "crosspackagesource";
+    protected static final String CROSS_PACKAGE_SOURCE_ID = "CrossPackageSource";
+    protected static final String CROSS_PACKAGE_TARGET = "crosspackagetarget";
+    protected static final String CROSS_PACKAGE_TARGET_ID = "CrossPackageTarget";
+
+    protected static final String NAMESPACE_PREFIX = "opencds.";
+
+    protected static final String WITH_TWO_LAYERS_DERIVED_LIBRARIES = "withtwolayersderivedlibraries";
+    protected static final String WITH_TWO_LAYERS_DERIVED_LIBRARIES_UPPER = "WithTwoLayersDerivedLibraries";
+
+    protected static final String SIMPLE_ALPHA_NAMESPACE = NAMESPACE_PREFIX + SIMPLE_ALPHA_LOWER;
+    protected static final String SIMPLE_BRAVO_NAMESPACE = NAMESPACE_PREFIX + SIMPLE_BRAVO_LOWER;
+    protected static final String WITH_DERIVED_NAMESPACE = NAMESPACE_PREFIX + WITH_DERIVED_LIBRARY_LOWER;
+    protected static final String WITH_TWO_LAYERS_NAMESPACE = NAMESPACE_PREFIX + WITH_TWO_LAYERS_DERIVED_LIBRARIES;
+    protected static final String CROSS_PACKAGE_SOURCE_NAMESPACE = NAMESPACE_PREFIX + CROSS_PACKAGE_SOURCE;
+    protected static final String CROSS_PACKAGE_TARGET_NAMESPACE = NAMESPACE_PREFIX + CROSS_PACKAGE_TARGET;
+
+    protected static final String SIMPLE_ALPHA_TGZ = SIMPLE_ALPHA_LOWER + DOT_TGZ;
+    protected static final String SIMPLE_BRAVO_TGZ = SIMPLE_BRAVO_LOWER + DOT_TGZ;
+    protected static final Path WITH_DERIVED_LIBRARY_TGZ = Paths.get(WITH_DERIVED_LIBRARY_LOWER + DOT_TGZ);
+    protected static final Path WITH_TWO_LAYERS_DERIVED_LIBRARIES_TGZ =
+            Paths.get(WITH_TWO_LAYERS_DERIVED_LIBRARIES + DOT_TGZ);
+    protected static final Path CROSS_PACKAGE_SOURCE_TGZ = Paths.get(CROSS_PACKAGE_SOURCE + DOT_TGZ);
+    protected static final Path CROSS_PACKAGE_TARGET_TGZ = Paths.get(CROSS_PACKAGE_TARGET + DOT_TGZ);
+
+    protected static final String SLASH_MEASURE_SLASH = "/Measure/";
+    protected static final String SLASH_LIBRARY_SLASH = "/Library/";
+
+    private static final String PIPE = "|";
+    protected static final String VERSION_0_1 = "0.1";
+    protected static final String VERSION_0_2 = "0.2";
+    protected static final String VERSION_0_3 = "0.3";
+    protected static final String VERSION_0_4 = "0.4";
+    protected static final String VERSION_0_5 = "0.5";
+
+    protected static final String SIMPLE_ALPHA_NAMESPACE_URL = "http://simplealpha.npm.opencds.org";
+    protected static final String SIMPLE_BRAVO_NAMESPACE_URL = "http://simplebravo.npm.opencds.org";
+    protected static final String WITH_DERIVED_URL = "http://withderivedlibrary.npm.opencds.org";
+    protected static final String WITH_TWO_LAYERS_DERIVED_URL = "http://withtwolayersderivedlibraries.npm.opencds.org";
+    protected static final String CROSS_PACKAGE_SOURCE_URL = "http://crosspackagesource.npm.opencds.org";
+    protected static final String CROSS_PACKAGE_TARGET_URL = "http://crosspackagetarget.npm.opencds.org";
+
+    protected static final String MEASURE_URL_ALPHA =
+            SIMPLE_ALPHA_NAMESPACE_URL + SLASH_MEASURE_SLASH + SIMPLE_ALPHA_MIXED;
+    protected static final String MEASURE_URL_BRAVO =
+            SIMPLE_BRAVO_NAMESPACE_URL + SLASH_MEASURE_SLASH + SIMPLE_BRAVO_MIXED;
+    protected static final String MEASURE_URL_WITH_DERIVED_LIBRARY =
+            WITH_DERIVED_URL + SLASH_MEASURE_SLASH + WITH_DERIVED_LIBRARY_MIXED;
+    protected static final String MEASURE_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES =
+            WITH_TWO_LAYERS_DERIVED_URL + SLASH_MEASURE_SLASH + WITH_TWO_LAYERS_DERIVED_LIBRARIES_UPPER;
+
+    protected static final String MEASURE_URL_CROSS_PACKAGE_SOURCE =
+            CROSS_PACKAGE_SOURCE_URL + SLASH_MEASURE_SLASH + CROSS_PACKAGE_SOURCE_ID;
+
+    protected static final String MEASURE_URL_CROSS_PACKAGE_TARGET =
+            CROSS_PACKAGE_TARGET_URL + SLASH_MEASURE_SLASH + CROSS_PACKAGE_TARGET_ID;
+
+    protected static final String LIBRARY_URL_ALPHA_NO_VERSION =
+            SIMPLE_ALPHA_NAMESPACE_URL + SLASH_LIBRARY_SLASH + SIMPLE_ALPHA_MIXED;
+    protected static final String LIBRARY_URL_ALPHA_WITH_VERSION = LIBRARY_URL_ALPHA_NO_VERSION + PIPE + VERSION_0_1;
+    protected static final String LIBRARY_URL_BRAVO_NO_VERSION =
+            SIMPLE_BRAVO_NAMESPACE_URL + SLASH_LIBRARY_SLASH + SIMPLE_BRAVO_MIXED;
+    protected static final String LIBRARY_URL_BRAVO_WITH_VERSION = LIBRARY_URL_BRAVO_NO_VERSION + PIPE + VERSION_0_1;
+
+    protected static final String LIBRARY_URL_WITH_DERIVED_LIBRARY_NO_VERSION =
+            WITH_DERIVED_URL + SLASH_LIBRARY_SLASH + WITH_DERIVED_LIBRARY_MIXED;
+    protected static final String LIBRARY_URL_WITH_DERIVED_LIBRARY_WITH_VERSION =
+            WITH_DERIVED_URL + SLASH_LIBRARY_SLASH + WITH_DERIVED_LIBRARY_MIXED + PIPE + VERSION_0_4;
+    protected static final String LIBRARY_URL_DERIVED_LIBRARY =
+            WITH_DERIVED_URL + SLASH_LIBRARY_SLASH + DERIVED_LIBRARY;
+
+    protected static final String LIBRARY_URL_CROSS_PACKAGE_SOURCE_NO_VERSION =
+            CROSS_PACKAGE_SOURCE_URL + SLASH_LIBRARY_SLASH + CROSS_PACKAGE_SOURCE_ID;
+    protected static final String LIBRARY_URL_CROSS_PACKAGE_SOURCE_WITH_VERSION =
+            LIBRARY_URL_CROSS_PACKAGE_SOURCE_NO_VERSION + PIPE + VERSION_0_2;
+    protected static final String LIBRARY_URL_CROSS_PACKAGE_TARGET_NO_VERSION =
+            CROSS_PACKAGE_TARGET_URL + SLASH_LIBRARY_SLASH + CROSS_PACKAGE_TARGET_ID;
+    protected static final String LIBRARY_URL_CROSS_PACKAGE_TARGET_WITH_VERSION =
+            LIBRARY_URL_CROSS_PACKAGE_TARGET_NO_VERSION + PIPE + VERSION_0_3;
+
+    protected static final String LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_NO_VERSION =
+            WITH_TWO_LAYERS_DERIVED_URL + SLASH_LIBRARY_SLASH + WITH_TWO_LAYERS_DERIVED_LIBRARIES_UPPER;
+    protected static final String LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_WITH_VERSION =
+            LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_NO_VERSION + PIPE + VERSION_0_5;
+
+    protected static final String LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1A =
+            WITH_TWO_LAYERS_DERIVED_URL + SLASH_LIBRARY_SLASH + DERIVED_LAYER_1_A;
+    protected static final String LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1B =
+            WITH_TWO_LAYERS_DERIVED_URL + SLASH_LIBRARY_SLASH + DERIVED_LAYER_1_B;
+    protected static final String LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2A =
+            WITH_TWO_LAYERS_DERIVED_URL + SLASH_LIBRARY_SLASH + DERIVED_LAYER_2_A;
+    protected static final String LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2B =
+            WITH_TWO_LAYERS_DERIVED_URL + SLASH_LIBRARY_SLASH + DERIVED_LAYER_2_B;
+
+    @Nonnull
+    protected abstract BaseNpmPackageLoaderInMemory setup(Path... npmPackagePaths);
+
+    @Nonnull
+    protected abstract BaseNpmPackageLoaderInMemory setup(List<Path> npmPackagePaths);
+}
diff --git a/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/NpmConfigDependencySubstitutorTest.java b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/NpmConfigDependencySubstitutorTest.java
new file mode 100644
index 0000000000..60e1016558
--- /dev/null
+++ b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/NpmConfigDependencySubstitutorTest.java
@@ -0,0 +1,29 @@
+package org.opencds.cqf.fhir.utility.npm;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.mock;
+
+import java.util.Optional;
+import org.junit.jupiter.api.Test;
+
+class NpmConfigDependencySubstitutorTest {
+
+    @Test
+    void present() {
+        var npmPackageLoader = mock(NpmPackageLoader.class);
+
+        var npmPackageLoaderFromSubstitutor =
+                NpmConfigDependencySubstitutor.substituteNpmPackageLoaderIfEmpty(Optional.of(npmPackageLoader));
+
+        assertNotEquals(NpmPackageLoader.R4_DEFAULT, npmPackageLoaderFromSubstitutor);
+        assertEquals(npmPackageLoader, npmPackageLoaderFromSubstitutor);
+    }
+
+    @Test
+    void empty() {
+        var npmPackageLoaderFromSubstitutor =
+                NpmConfigDependencySubstitutor.substituteNpmPackageLoaderIfEmpty(Optional.empty());
+
+        assertEquals(NpmPackageLoader.R4_DEFAULT, npmPackageLoaderFromSubstitutor);
+    }
+}
diff --git a/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/r4/NpmPackageLoaderR4Test.java b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/r4/NpmPackageLoaderR4Test.java
new file mode 100644
index 0000000000..f036cda55b
--- /dev/null
+++ b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/r4/NpmPackageLoaderR4Test.java
@@ -0,0 +1,612 @@
+package org.opencds.cqf.fhir.utility.npm.r4;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import ca.uhn.fhir.context.FhirVersionEnum;
+import jakarta.annotation.Nonnull;
+import jakarta.annotation.Nullable;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Stream;
+import org.hl7.cql.model.NamespaceInfo;
+import org.hl7.elm.r1.VersionedIdentifier;
+import org.hl7.fhir.r4.model.Attachment;
+import org.hl7.fhir.r4.model.CanonicalType;
+import org.hl7.fhir.r4.model.Library;
+import org.hl7.fhir.r4.model.Measure;
+import org.junit.jupiter.api.Test;
+import org.opencds.cqf.fhir.utility.adapter.ILibraryAdapter;
+import org.opencds.cqf.fhir.utility.adapter.r4.LibraryAdapter;
+import org.opencds.cqf.fhir.utility.npm.BaseNpmPackageLoaderInMemory;
+import org.opencds.cqf.fhir.utility.npm.BaseNpmPackageLoaderTest;
+
+@SuppressWarnings("squid:S2699")
+class NpmPackageLoaderR4Test extends BaseNpmPackageLoaderTest {
+
+    protected FhirVersionEnum fhirVersion = FhirVersionEnum.R4;
+
+    private static final String EXPECTED_CQL_ALPHA =
+            """
+        library opencds.simplealpha.SimpleAlpha
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+
+        parameter "Measurement Period" Interval<DateTime>
+          default Interval[@2021-01-01T00:00:00.0-06:00, @2022-01-01T00:00:00.0-06:00)
+
+        context Patient
+
+        define "Initial Population":
+            exists ("Encounter Finished")
+
+        define "Encounter Finished":
+          [Encounter] E
+            where E.status = 'finished'
+        """;
+
+    private static final String EXPECTED_CQL_BRAVO =
+            """
+        library opencds.simplealpha.SimpleBravo
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+
+        parameter "Measurement Period" Interval<DateTime>
+          default Interval[@2024-01-01T00:00:00.0-06:00, @2025-01-01T00:00:00.0-06:00)
+
+        context Patient
+
+        define "Initial Population":
+            exists ("Encounter Planned")
+
+        define "Encounter Planned":
+          [Encounter] E
+            where E.status = 'planned'
+        """;
+
+    private static final String EXPECTED_CQL_WITH_DERIVED =
+            """
+        library opencds.withderivedlibrary WithDerivedLibrary version '0.4'
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+        include DerivedLibrary version '0.4'
+
+        parameter "Measurement Period" Interval<DateTime>
+            default Interval[@2021-01-01T00:00:00.0-06:00, @2022-01-01T00:00:00.0-06:00)
+
+        context Patient
+
+        define "Initial Population":
+            exists (DerivedLibrary."Encounter Finished")
+        """;
+
+    private static final String EXPECTED_CQL_DERIVED =
+            """
+        library opencds.withderivedlibrary.DerivedLibrary version '0.4'
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+
+        context Patient
+
+        define "Encounter Finished":
+          [Encounter] E
+            where E.status = 'finished'
+        """;
+
+    private static final String EXPECTED_CQL_DERIVED_TWO_LAYERS =
+            """
+        library opencds.withtwolayersderivedlibraries.WithTwoLayersDerivedLibraries version '0.5'
+
+        using FHIR version '4.0.1'
+
+        include DerivedLayer1a version '0.5'
+        include DerivedLayer1b version '0.5'
+
+        parameter "Measurement Period" Interval<DateTime>
+            default Interval[@2022-01-01T00:00:00.0-06:00, @2023-01-01T00:00:00.0-06:00)
+
+        context Patient
+
+        define "Initial Population":
+            DerivedLayer1a."Initial Population"
+
+        define "Denominator":
+            DerivedLayer1b."Denominator"
+
+        define "Numerator":
+            DerivedLayer1b."Numerator"
+        """;
+
+    private static final String EXPECTED_CQL_DERIVED_1_A =
+            """
+        library opencds.withtwolayersderivedlibraries.DerivedLayer1a version '0.5'
+
+        using FHIR version '4.0.1'
+
+        include DerivedLayer2a version '0.5'
+        include DerivedLayer2b version '0.5'
+
+        context Patient
+
+        define "Initial Population":
+            DerivedLayer2a."Initial Population"
+        """;
+
+    private static final String EXPECTED_CQL_DERIVED_1_B =
+            """
+        library opencds.withtwolayersderivedlibraries.DerivedLayer1b version '0.5'
+
+        using FHIR version '4.0.1'
+
+        include DerivedLayer2a version '0.5'
+        include DerivedLayer2b version '0.5'
+
+        context Patient
+
+        define "Denominator":
+            DerivedLayer2a."Denominator"
+
+        define "Numerator":
+            DerivedLayer2b."Numerator"
+        """;
+
+    private static final String EXPECTED_CQL_DERIVED_2_A =
+            """
+        library opencds.withtwolayersderivedlibraries.DerivedLayer2a version '0.5'
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+
+        context Patient
+
+        define "Initial Population":
+            exists ("Encounter Finished")
+
+        define "Denominator":
+            exists ("Encounter Planned")
+
+        define "Encounter Finished":
+          [Encounter] E
+            where E.status = 'finished'
+
+        define "Encounter Planned":
+          [Encounter] E
+            where E.status = 'planned'
+        """;
+
+    private static final String EXPECTED_CQL_DERIVED_2_B =
+            """
+        library opencds.withtwolayersderivedlibraries.DerivedLayer2b version '0.5'
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+
+        parameter "Measurement Period" Interval<DateTime>
+          default Interval[@2021-01-01T00:00:00.0-06:00, @2022-01-01T00:00:00.0-06:00)
+
+        context Patient
+
+        define "Numerator":
+            exists ("Encounter Triaged")
+
+        define "Encounter Triaged":
+          [Encounter] E
+            where E.status = 'triaged'
+        """;
+
+    private static final String EXPECTED_CQL_CROSS_SOURCE =
+            """
+        library opencds.crosspackagesource.CrossPackageSource version '0.2'
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+        include opencds.crosspackagetarget.CrossPackageTarget version '0.3' called CrossPackageTarget
+
+        parameter "Measurement Period" Interval<DateTime>
+            default Interval[@2020-01-01T00:00:00.0-06:00, @2021-01-01T00:00:00.0-06:00)
+
+        context Patient
+
+        define "Initial Population":
+            exists (CrossPackageTarget."Encounter Finished")
+        """;
+
+    private static final String EXPECTED_CQL_CROSS_TARGET =
+            """
+        library opencds.crosspackagetarget.CrossPackageTarget version '0.3'
+
+        using FHIR version '4.0.1'
+
+        include FHIRHelpers version '4.0.1' called FHIRHelpers
+
+        context Patient
+
+        define "Encounter Finished":
+          [Encounter] E
+            where E.status = 'finished'
+        """;
+
+    @Test
+    void simpleAlpha() {
+        final BaseNpmPackageLoaderInMemory loader = setup(Path.of(SIMPLE_ALPHA_TGZ));
+
+        final Optional<Measure> optMeasure =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_ALPHA));
+
+        verifyMeasure(optMeasure.orElse(null), MEASURE_URL_ALPHA, VERSION_0_1, LIBRARY_URL_ALPHA_WITH_VERSION);
+
+        final Optional<Library> optLibrary =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_ALPHA_WITH_VERSION));
+
+        verifyLibrary(optLibrary.orElse(null), LIBRARY_URL_ALPHA_NO_VERSION, VERSION_0_1, EXPECTED_CQL_ALPHA);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        final NamespaceInfo namespaceInfo = allNamespaceInfos.get(0);
+
+        assertEquals(SIMPLE_ALPHA_NAMESPACE, namespaceInfo.getName());
+        assertEquals(SIMPLE_ALPHA_NAMESPACE_URL, namespaceInfo.getUri());
+    }
+
+    @Test
+    void simpleBravo() {
+        final BaseNpmPackageLoaderInMemory loader = setup(Path.of(SIMPLE_BRAVO_TGZ));
+
+        final Optional<Measure> optMeasure =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_BRAVO));
+
+        verifyMeasure(optMeasure.orElse(null), MEASURE_URL_BRAVO, VERSION_0_1, LIBRARY_URL_BRAVO_WITH_VERSION);
+
+        final Optional<Library> optLibrary =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_BRAVO_WITH_VERSION));
+
+        verifyLibrary(optLibrary.orElse(null), LIBRARY_URL_BRAVO_NO_VERSION, VERSION_0_1, EXPECTED_CQL_BRAVO);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        final NamespaceInfo namespaceInfo = allNamespaceInfos.get(0);
+
+        assertEquals(SIMPLE_BRAVO_NAMESPACE, namespaceInfo.getName());
+        assertEquals(SIMPLE_BRAVO_NAMESPACE_URL, namespaceInfo.getUri());
+    }
+
+    @Test
+    void multiplePackages() {
+        final BaseNpmPackageLoaderInMemory loader = setup(
+                Stream.of(SIMPLE_ALPHA_TGZ, SIMPLE_BRAVO_TGZ).map(Paths::get).toList());
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(2, allNamespaceInfos.size());
+
+        assertTrue(allNamespaceInfos.contains(new NamespaceInfo(SIMPLE_ALPHA_NAMESPACE, SIMPLE_ALPHA_NAMESPACE_URL)));
+        assertTrue(allNamespaceInfos.contains(new NamespaceInfo(SIMPLE_BRAVO_NAMESPACE, SIMPLE_BRAVO_NAMESPACE_URL)));
+
+        final Optional<Measure> optMeasureAlpha =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_ALPHA));
+
+        verifyMeasure(optMeasureAlpha.orElse(null), MEASURE_URL_ALPHA, VERSION_0_1, LIBRARY_URL_ALPHA_WITH_VERSION);
+
+        final Optional<Library> optLibraryAlpha =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_ALPHA_WITH_VERSION));
+
+        verifyLibrary(optLibraryAlpha.orElse(null), LIBRARY_URL_ALPHA_NO_VERSION, VERSION_0_1, EXPECTED_CQL_ALPHA);
+
+        final Optional<Measure> optMeasureBravo =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_ALPHA));
+
+        verifyMeasure(optMeasureBravo.orElse(null), MEASURE_URL_ALPHA, VERSION_0_1, LIBRARY_URL_ALPHA_WITH_VERSION);
+
+        final Optional<Library> optLibraryBravo =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_BRAVO_WITH_VERSION));
+
+        verifyLibrary(optLibraryBravo.orElse(null), LIBRARY_URL_BRAVO_NO_VERSION, VERSION_0_1, EXPECTED_CQL_BRAVO);
+    }
+
+    @Test
+    void derivedLibrary() {
+
+        final BaseNpmPackageLoaderInMemory loader = setup(WITH_DERIVED_LIBRARY_TGZ);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        assertTrue(allNamespaceInfos.contains(new NamespaceInfo(WITH_DERIVED_NAMESPACE, WITH_DERIVED_URL)));
+
+        final Optional<Measure> optMeasureWithDerived =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_WITH_DERIVED_LIBRARY));
+
+        verifyMeasure(
+                optMeasureWithDerived.orElse(null),
+                MEASURE_URL_WITH_DERIVED_LIBRARY,
+                VERSION_0_4,
+                LIBRARY_URL_WITH_DERIVED_LIBRARY_WITH_VERSION);
+
+        final Optional<Library> optLibraryWithDerived =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_WITH_DERIVED_LIBRARY_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryWithDerived.orElse(null),
+                LIBRARY_URL_WITH_DERIVED_LIBRARY_NO_VERSION,
+                VERSION_0_4,
+                EXPECTED_CQL_WITH_DERIVED);
+
+        final Optional<Library> optLibraryDerived =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_DERIVED_LIBRARY));
+
+        verifyLibrary(optLibraryDerived.orElse(null), LIBRARY_URL_DERIVED_LIBRARY, VERSION_0_4, EXPECTED_CQL_DERIVED);
+    }
+
+    @Test
+    void derivedLibraryTwoLayers() {
+
+        final BaseNpmPackageLoaderInMemory loader = setup(WITH_TWO_LAYERS_DERIVED_LIBRARIES_TGZ);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        assertTrue(
+                allNamespaceInfos.contains(new NamespaceInfo(WITH_TWO_LAYERS_NAMESPACE, WITH_TWO_LAYERS_DERIVED_URL)));
+
+        final Optional<Measure> optMeasureWithTwoDerived =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES));
+
+        verifyMeasure(
+                optMeasureWithTwoDerived.orElse(null),
+                MEASURE_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES,
+                VERSION_0_5,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_WITH_VERSION);
+
+        final Optional<Library> optLibraryWithTwoDerived = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_NO_VERSION,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_TWO_LAYERS);
+
+        final Optional<Library> optLibraryWithTwoDerived1a = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1A));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived1a.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_A);
+
+        final Optional<Library> optLibraryWithTwoDerived1b = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1B));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived1b.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_B);
+
+        final Optional<Library> optLibraryWithTwoDerived2a = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2A));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived2a.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_A);
+
+        final Optional<Library> optLibraryWithTwoDerived2b = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2B));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived2b.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_B);
+
+        final ILibraryAdapter libraryAdapter1a = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_1_A)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter1a,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_A);
+
+        final ILibraryAdapter libraryAdapter1b = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_1_B)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter1b,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_B);
+
+        final ILibraryAdapter libraryAdapter2a = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_2_A)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter2a,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_A);
+
+        final ILibraryAdapter libraryAdapter2b = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_2_B)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter2b,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_B);
+    }
+
+    @Test
+    void crossPackage() {
+
+        final BaseNpmPackageLoaderInMemory loader = setup(CROSS_PACKAGE_SOURCE_TGZ, CROSS_PACKAGE_TARGET_TGZ);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(2, allNamespaceInfos.size());
+
+        assertTrue(allNamespaceInfos.contains(
+                new NamespaceInfo(CROSS_PACKAGE_SOURCE_NAMESPACE, CROSS_PACKAGE_SOURCE_URL)));
+        assertTrue(allNamespaceInfos.contains(
+                new NamespaceInfo(CROSS_PACKAGE_TARGET_NAMESPACE, CROSS_PACKAGE_TARGET_URL)));
+
+        final Optional<Measure> optMeasureCrossSource =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_CROSS_PACKAGE_SOURCE));
+
+        verifyMeasure(
+                optMeasureCrossSource.orElse(null),
+                MEASURE_URL_CROSS_PACKAGE_SOURCE,
+                VERSION_0_2,
+                LIBRARY_URL_CROSS_PACKAGE_SOURCE_WITH_VERSION);
+
+        final Optional<Library> optLibraryCrossSource =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_CROSS_PACKAGE_SOURCE_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryCrossSource.orElse(null),
+                LIBRARY_URL_CROSS_PACKAGE_SOURCE_NO_VERSION,
+                VERSION_0_2,
+                EXPECTED_CQL_CROSS_SOURCE);
+
+        final Optional<Measure> optMeasureCrossTarget =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_CROSS_PACKAGE_TARGET));
+
+        verifyMeasure(
+                optMeasureCrossTarget.orElse(null),
+                MEASURE_URL_CROSS_PACKAGE_TARGET,
+                VERSION_0_3,
+                LIBRARY_URL_CROSS_PACKAGE_TARGET_WITH_VERSION);
+
+        final Optional<Library> optLibraryCrossTarget =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_CROSS_PACKAGE_TARGET_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryCrossTarget.orElse(null),
+                LIBRARY_URL_CROSS_PACKAGE_TARGET_NO_VERSION,
+                VERSION_0_3,
+                EXPECTED_CQL_CROSS_TARGET);
+
+        final ILibraryAdapter libraryAdapterSource = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(CROSS_PACKAGE_SOURCE_ID)
+                        .withVersion(VERSION_0_2)
+                        .withSystem(CROSS_PACKAGE_SOURCE_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapterSource,
+                LIBRARY_URL_CROSS_PACKAGE_SOURCE_NO_VERSION,
+                VERSION_0_2,
+                EXPECTED_CQL_CROSS_SOURCE);
+
+        final ILibraryAdapter libraryAdapterTarget = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(CROSS_PACKAGE_TARGET_ID)
+                        .withVersion(VERSION_0_3)
+                        .withSystem(CROSS_PACKAGE_TARGET_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapterTarget,
+                LIBRARY_URL_CROSS_PACKAGE_TARGET_NO_VERSION,
+                VERSION_0_3,
+                EXPECTED_CQL_CROSS_TARGET);
+    }
+
+    protected void verifyMeasure(
+            @Nullable Measure measure, String measureUrl, String version, String expectedLibraryUrl) {
+
+        assertNotNull(measure, "Could not find measure with url: %s".formatted(measureUrl));
+
+        assertEquals(measureUrl, measure.getUrl());
+
+        assertEquals(version, measure.getVersion());
+
+        final List<CanonicalType> libraryUrls = measure.getLibrary();
+        assertEquals(1, libraryUrls.size());
+        final CanonicalType libraryUrl = libraryUrls.get(0);
+        assertEquals(expectedLibraryUrl, libraryUrl.asStringValue());
+    }
+
+    private void verifyLibrary(
+            @Nullable ILibraryAdapter libraryAdapter, String expectedLibraryUrl, String version, String expectedCql) {
+
+        assertNotNull(libraryAdapter, "Could not find library with url: %s".formatted(expectedLibraryUrl));
+
+        assertInstanceOf(LibraryAdapter.class, libraryAdapter);
+
+        verifyLibrary(((LibraryAdapter) libraryAdapter).get(), expectedLibraryUrl, version, expectedCql);
+    }
+
+    private void verifyLibrary(
+            @Nullable Library library, String expectedLibraryUrl, String version, String expectedCql) {
+
+        assertNotNull(library, "Could not find library with url: %s".formatted(expectedLibraryUrl));
+
+        assertEquals(expectedLibraryUrl, library.getUrl());
+
+        assertEquals(version, library.getVersion());
+
+        final List<Attachment> attachments = library.getContent();
+        assertEquals(1, attachments.size());
+        final Attachment attachment = attachments.get(0);
+        assertEquals("text/cql", attachment.getContentType());
+        final byte[] attachmentData = attachment.getData();
+        final String cql = new String(attachmentData, StandardCharsets.UTF_8);
+
+        assertEquals(expectedCql, cql);
+    }
+
+    @Nonnull
+    @Override
+    protected BaseNpmPackageLoaderInMemory setup(Path... npmPackagePaths) {
+        return R4NpmPackageLoaderInMemory.fromNpmPackageClasspath(getClass(), npmPackagePaths);
+    }
+
+    @Nonnull
+    @Override
+    protected BaseNpmPackageLoaderInMemory setup(List<Path> npmPackagePaths) {
+        return R4NpmPackageLoaderInMemory.fromNpmPackageClasspath(getClass(), npmPackagePaths);
+    }
+}
diff --git a/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/r5/NpmPackageLoaderR5Test.java b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/r5/NpmPackageLoaderR5Test.java
new file mode 100644
index 0000000000..0bc7dc15cd
--- /dev/null
+++ b/cqf-fhir-utility/src/test/java/org/opencds/cqf/fhir/utility/npm/r5/NpmPackageLoaderR5Test.java
@@ -0,0 +1,610 @@
+package org.opencds.cqf.fhir.utility.npm.r5;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import ca.uhn.fhir.context.FhirVersionEnum;
+import jakarta.annotation.Nonnull;
+import jakarta.annotation.Nullable;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Stream;
+import org.hl7.cql.model.NamespaceInfo;
+import org.hl7.elm.r1.VersionedIdentifier;
+import org.hl7.fhir.r5.model.Attachment;
+import org.hl7.fhir.r5.model.CanonicalType;
+import org.hl7.fhir.r5.model.Library;
+import org.hl7.fhir.r5.model.Measure;
+import org.junit.jupiter.api.Test;
+import org.opencds.cqf.fhir.utility.adapter.ILibraryAdapter;
+import org.opencds.cqf.fhir.utility.adapter.r5.LibraryAdapter;
+import org.opencds.cqf.fhir.utility.npm.BaseNpmPackageLoaderInMemory;
+import org.opencds.cqf.fhir.utility.npm.BaseNpmPackageLoaderTest;
+
+@SuppressWarnings("squid:S2699")
+class NpmPackageLoaderR5Test extends BaseNpmPackageLoaderTest {
+
+    protected FhirVersionEnum fhirVersion = FhirVersionEnum.R5;
+
+    private static final String EXPECTED_CQL_ALPHA =
+            """
+            library opencds.simplealpha.SimpleAlpha
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '5.0.1' called FHIRHelpers
+
+            parameter "Measurement Period" Interval<DateTime>
+              default Interval[@2021-01-01T00:00:00.0-06:00, @2022-01-01T00:00:00.0-06:00)
+
+            context Patient
+
+            define "Initial Population":
+                exists ("Encounter Finished")
+
+            define "Encounter Finished":
+              [Encounter] E
+                where E.status = 'finished'
+            """;
+    private static final String EXPECTED_CQL_BRAVO =
+            """
+            library opencds.simplealpha.SimpleBravo
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '4.0.1' called FHIRHelpers
+
+            parameter "Measurement Period" Interval<DateTime>
+              default Interval[@2024-01-01T00:00:00.0-06:00, @2025-01-01T00:00:00.0-06:00)
+
+            context Patient
+
+            define "Initial Population":
+                exists ("Encounter Planned")
+
+            define "Encounter Planned":
+              [Encounter] E
+                where E.status = 'planned'
+            """;
+    private static final String EXPECTED_CQL_WITH_DERIVED =
+            """
+            library opencds.withderivedlibrary WithDerivedLibrary version '0.4'
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '5.0.1' called FHIRHelpers
+            include DerivedLibrary version '0.4'
+
+            parameter "Measurement Period" Interval<DateTime>
+                default Interval[@2021-01-01T00:00:00.0-06:00, @2022-01-01T00:00:00.0-06:00)
+
+            context Patient
+
+            define "Initial Population":
+                exists (DerivedLibrary."Encounter Finished")
+            """;
+    private static final String EXPECTED_CQL_DERIVED =
+            """
+            library opencds.withderivedlibrary.DerivedLibrary version '0.4'
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '5.0.1' called FHIRHelpers
+
+            context Patient
+
+            define "Encounter Finished":
+              [Encounter] E
+                where E.status = 'finished'
+            """;
+
+    private static final String EXPECTED_CQL_DERIVED_TWO_LAYERS =
+            """
+            library opencds.withtwolayersderivedlibraries.WithTwoLayersDerivedLibraries version '0.5'
+
+            using FHIR version '5.0.1'
+
+            include DerivedLayer1a version '0.5'
+            include DerivedLayer1b version '0.5'
+
+            parameter "Measurement Period" Interval<DateTime>
+                default Interval[@2022-01-01T00:00:00.0-06:00, @2023-01-01T00:00:00.0-06:00)
+
+            context Patient
+
+            define "Initial Population":
+                DerivedLayer1a."Initial Population"
+
+            define "Denominator":
+                DerivedLayer1b."Denominator"
+
+            define "Numerator":
+                DerivedLayer1b."Numerator"
+            """;
+
+    private static final String EXPECTED_CQL_DERIVED_1_A =
+            """
+            library opencds.withtwolayersderivedlibraries.DerivedLayer1a version '0.5'
+
+            using FHIR version '5.0.1'
+
+            include DerivedLayer2a version '0.5'
+            include DerivedLayer2b version '0.5'
+
+            context Patient
+
+            define "Initial Population":
+                DerivedLayer2a."Initial Population"
+            """;
+
+    private static final String EXPECTED_CQL_DERIVED_1_B =
+            """
+            library opencds.withtwolayersderivedlibraries.DerivedLayer1b version '0.5'
+
+            using FHIR version '5.0.1'
+
+            include DerivedLayer2a version '0.5'
+            include DerivedLayer2b version '0.5'
+
+            context Patient
+
+            define "Denominator":
+                DerivedLayer2a."Denominator"
+
+            define "Numerator":
+                DerivedLayer2b."Numerator"
+            """;
+
+    private static final String EXPECTED_CQL_DERIVED_2_A =
+            """
+            library opencds.withtwolayersderivedlibraries.DerivedLayer2a version '0.5'
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '5.0.1' called FHIRHelpers
+
+            context Patient
+
+            define "Initial Population":
+                exists ("Encounter Finished")
+
+            define "Denominator":
+                exists ("Encounter Planned")
+
+            define "Encounter Finished":
+              [Encounter] E
+                where E.status = 'finished'
+
+            define "Encounter Planned":
+              [Encounter] E
+                where E.status = 'planned'
+            """;
+
+    private static final String EXPECTED_CQL_DERIVED_2_B =
+            """
+            library opencds.withtwolayersderivedlibraries.DerivedLayer2b version '0.5'
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '5.0.1' called FHIRHelpers
+
+            parameter "Measurement Period" Interval<DateTime>
+              default Interval[@2021-01-01T00:00:00.0-06:00, @2022-01-01T00:00:00.0-06:00)
+
+            context Patient
+
+            define "Numerator":
+                exists ("Encounter Triaged")
+
+            define "Encounter Triaged":
+              [Encounter] E
+                where E.status = 'triaged'
+            """;
+
+    private static final String EXPECTED_CQL_CROSS_SOURCE =
+            """
+            library opencds.crosspackagesource.CrossPackageSource version '0.2'
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '4.0.1' called FHIRHelpers
+            include opencds.crosspackagetarget.CrossPackageTarget version '0.3' called CrossPackageTarget
+
+            parameter "Measurement Period" Interval<DateTime>
+                default Interval[@2020-01-01T00:00:00.0-06:00, @2021-01-01T00:00:00.0-06:00)
+
+            context Patient
+
+            define "Initial Population":
+                exists (CrossPackageTarget."Encounter Finished")
+            """;
+
+    private static final String EXPECTED_CQL_CROSS_TARGET =
+            """
+            library opencds.crosspackagetarget.CrossPackageTarget version '0.3'
+
+            using FHIR version '5.0.1'
+
+            include FHIRHelpers version '5.0.1' called FHIRHelpers
+
+            context Patient
+
+            define "Encounter Finished":
+              [Encounter] E
+                where E.status = 'finished'
+            """;
+
+    @Test
+    void simpleAlpha() {
+        final BaseNpmPackageLoaderInMemory loader = setup(Path.of(SIMPLE_ALPHA_TGZ));
+
+        final Optional<Measure> optMeasure =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_ALPHA));
+
+        verifyMeasure(optMeasure.orElse(null), MEASURE_URL_ALPHA, VERSION_0_1, LIBRARY_URL_ALPHA_WITH_VERSION);
+
+        final Optional<Library> optLibrary =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_ALPHA_WITH_VERSION));
+
+        verifyLibrary(optLibrary.orElse(null), LIBRARY_URL_ALPHA_NO_VERSION, VERSION_0_1, EXPECTED_CQL_ALPHA);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        final NamespaceInfo namespaceInfo = allNamespaceInfos.get(0);
+
+        assertEquals(SIMPLE_ALPHA_NAMESPACE, namespaceInfo.getName());
+        assertEquals(SIMPLE_ALPHA_NAMESPACE_URL, namespaceInfo.getUri());
+    }
+
+    @Test
+    void simpleBravo() {
+        final BaseNpmPackageLoaderInMemory loader = setup(Path.of(SIMPLE_BRAVO_TGZ));
+
+        final Optional<Measure> optMeasure =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_BRAVO));
+
+        verifyMeasure(optMeasure.orElse(null), MEASURE_URL_BRAVO, VERSION_0_1, LIBRARY_URL_BRAVO_WITH_VERSION);
+
+        final Optional<Library> optLibrary =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_BRAVO_WITH_VERSION));
+
+        verifyLibrary(optLibrary.orElse(null), LIBRARY_URL_BRAVO_NO_VERSION, VERSION_0_1, EXPECTED_CQL_BRAVO);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        final NamespaceInfo namespaceInfo = allNamespaceInfos.get(0);
+
+        assertEquals(SIMPLE_BRAVO_NAMESPACE, namespaceInfo.getName());
+        assertEquals(SIMPLE_BRAVO_NAMESPACE_URL, namespaceInfo.getUri());
+    }
+
+    @Test
+    void multiplePackages() {
+        final BaseNpmPackageLoaderInMemory loader = R5NpmPackageLoaderInMemory.fromNpmPackageClasspath(
+                getClass(),
+                Stream.of(SIMPLE_ALPHA_TGZ, SIMPLE_BRAVO_TGZ).map(Paths::get).toList());
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(2, allNamespaceInfos.size());
+
+        assertTrue(allNamespaceInfos.contains(new NamespaceInfo(SIMPLE_ALPHA_NAMESPACE, SIMPLE_ALPHA_NAMESPACE_URL)));
+        assertTrue(allNamespaceInfos.contains(new NamespaceInfo(SIMPLE_BRAVO_NAMESPACE, SIMPLE_BRAVO_NAMESPACE_URL)));
+
+        final Optional<Measure> optMeasureAlpha =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_ALPHA));
+
+        verifyMeasure(optMeasureAlpha.orElse(null), MEASURE_URL_ALPHA, VERSION_0_1, LIBRARY_URL_ALPHA_WITH_VERSION);
+
+        final Optional<Library> optLibraryAlpha =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_ALPHA_WITH_VERSION));
+
+        verifyLibrary(optLibraryAlpha.orElse(null), LIBRARY_URL_ALPHA_NO_VERSION, VERSION_0_1, EXPECTED_CQL_ALPHA);
+
+        final Optional<Measure> optMeasureBravo =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_ALPHA));
+
+        verifyMeasure(optMeasureBravo.orElse(null), MEASURE_URL_ALPHA, VERSION_0_1, LIBRARY_URL_ALPHA_WITH_VERSION);
+
+        final Optional<Library> optLibraryBravo =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_BRAVO_WITH_VERSION));
+
+        verifyLibrary(optLibraryBravo.orElse(null), LIBRARY_URL_BRAVO_NO_VERSION, VERSION_0_1, EXPECTED_CQL_BRAVO);
+    }
+
+    @Test
+    void derivedLibrary() {
+
+        final BaseNpmPackageLoaderInMemory loader = setup(WITH_DERIVED_LIBRARY_TGZ);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        assertTrue(allNamespaceInfos.contains(new NamespaceInfo(WITH_DERIVED_NAMESPACE, WITH_DERIVED_URL)));
+
+        final Optional<Measure> optMeasureWithDerived =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_WITH_DERIVED_LIBRARY));
+
+        verifyMeasure(
+                optMeasureWithDerived.orElse(null),
+                MEASURE_URL_WITH_DERIVED_LIBRARY,
+                VERSION_0_4,
+                LIBRARY_URL_WITH_DERIVED_LIBRARY_WITH_VERSION);
+
+        final Optional<Library> optLibraryWithDerived =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_WITH_DERIVED_LIBRARY_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryWithDerived.orElse(null),
+                LIBRARY_URL_WITH_DERIVED_LIBRARY_NO_VERSION,
+                VERSION_0_4,
+                EXPECTED_CQL_WITH_DERIVED);
+
+        final Optional<Library> optLibraryDerived =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_DERIVED_LIBRARY));
+
+        verifyLibrary(optLibraryDerived.orElse(null), LIBRARY_URL_DERIVED_LIBRARY, VERSION_0_4, EXPECTED_CQL_DERIVED);
+    }
+
+    @Test
+    void derivedLibraryTwoLayers() {
+
+        final BaseNpmPackageLoaderInMemory loader = setup(WITH_TWO_LAYERS_DERIVED_LIBRARIES_TGZ);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(1, allNamespaceInfos.size());
+
+        assertTrue(
+                allNamespaceInfos.contains(new NamespaceInfo(WITH_TWO_LAYERS_NAMESPACE, WITH_TWO_LAYERS_DERIVED_URL)));
+
+        final Optional<Measure> optMeasureWithTwoDerived =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES));
+
+        verifyMeasure(
+                optMeasureWithTwoDerived.orElse(null),
+                MEASURE_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES,
+                VERSION_0_5,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_WITH_VERSION);
+
+        final Optional<Library> optLibraryWithTwoDerived = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARIES_NO_VERSION,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_TWO_LAYERS);
+
+        final Optional<Library> optLibraryWithTwoDerived1a = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1A));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived1a.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_A);
+
+        final Optional<Library> optLibraryWithTwoDerived1b = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1B));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived1b.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_B);
+
+        final Optional<Library> optLibraryWithTwoDerived2a = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2A));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived2a.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_A);
+
+        final Optional<Library> optLibraryWithTwoDerived2b = loader.loadNpmResource(
+                Library.class, new CanonicalType(LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2B));
+
+        verifyLibrary(
+                optLibraryWithTwoDerived2b.orElse(null),
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_B);
+
+        final ILibraryAdapter libraryAdapter1a = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_1_A)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter1a,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_A);
+
+        final ILibraryAdapter libraryAdapter1b = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_1_B)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter1b,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_1B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_1_B);
+
+        final ILibraryAdapter libraryAdapter2a = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_2_A)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter2a,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2A,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_A);
+
+        final ILibraryAdapter libraryAdapter2b = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(DERIVED_LAYER_2_B)
+                        .withVersion(VERSION_0_5)
+                        .withSystem(WITH_TWO_LAYERS_DERIVED_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapter2b,
+                LIBRARY_URL_WITH_TWO_LAYERS_DERIVED_LIBRARY_2B,
+                VERSION_0_5,
+                EXPECTED_CQL_DERIVED_2_B);
+    }
+
+    @Test
+    void crossPackage() {
+
+        final BaseNpmPackageLoaderInMemory loader = setup(CROSS_PACKAGE_SOURCE_TGZ, CROSS_PACKAGE_TARGET_TGZ);
+
+        final List<NamespaceInfo> allNamespaceInfos =
+                loader.getNamespaceManager().getAllNamespaceInfos();
+
+        assertEquals(2, allNamespaceInfos.size());
+
+        assertTrue(allNamespaceInfos.contains(
+                new NamespaceInfo(CROSS_PACKAGE_SOURCE_NAMESPACE, CROSS_PACKAGE_SOURCE_URL)));
+        assertTrue(allNamespaceInfos.contains(
+                new NamespaceInfo(CROSS_PACKAGE_TARGET_NAMESPACE, CROSS_PACKAGE_TARGET_URL)));
+
+        final Optional<Measure> optMeasureCrossSource =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_CROSS_PACKAGE_SOURCE));
+
+        verifyMeasure(
+                optMeasureCrossSource.orElse(null),
+                MEASURE_URL_CROSS_PACKAGE_SOURCE,
+                VERSION_0_2,
+                LIBRARY_URL_CROSS_PACKAGE_SOURCE_WITH_VERSION);
+
+        final Optional<Library> optLibraryCrossSource =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_CROSS_PACKAGE_SOURCE_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryCrossSource.orElse(null),
+                LIBRARY_URL_CROSS_PACKAGE_SOURCE_NO_VERSION,
+                VERSION_0_2,
+                EXPECTED_CQL_CROSS_SOURCE);
+
+        final Optional<Measure> optMeasureCrossTarget =
+                loader.loadNpmResource(Measure.class, new CanonicalType(MEASURE_URL_CROSS_PACKAGE_TARGET));
+
+        verifyMeasure(
+                optMeasureCrossTarget.orElse(null),
+                MEASURE_URL_CROSS_PACKAGE_TARGET,
+                VERSION_0_3,
+                LIBRARY_URL_CROSS_PACKAGE_TARGET_WITH_VERSION);
+
+        final Optional<Library> optLibraryCrossTarget =
+                loader.loadNpmResource(Library.class, new CanonicalType(LIBRARY_URL_CROSS_PACKAGE_TARGET_WITH_VERSION));
+
+        verifyLibrary(
+                optLibraryCrossTarget.orElse(null),
+                LIBRARY_URL_CROSS_PACKAGE_TARGET_NO_VERSION,
+                VERSION_0_3,
+                EXPECTED_CQL_CROSS_TARGET);
+
+        final ILibraryAdapter libraryAdapterSource = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(CROSS_PACKAGE_SOURCE_ID)
+                        .withVersion(VERSION_0_2)
+                        .withSystem(CROSS_PACKAGE_SOURCE_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapterSource,
+                LIBRARY_URL_CROSS_PACKAGE_SOURCE_NO_VERSION,
+                VERSION_0_2,
+                EXPECTED_CQL_CROSS_SOURCE);
+
+        final ILibraryAdapter libraryAdapterTarget = loader.findMatchingLibrary(new VersionedIdentifier()
+                        .withId(CROSS_PACKAGE_TARGET_ID)
+                        .withVersion(VERSION_0_3)
+                        .withSystem(CROSS_PACKAGE_TARGET_URL))
+                .orElse(null);
+
+        verifyLibrary(
+                libraryAdapterTarget,
+                LIBRARY_URL_CROSS_PACKAGE_TARGET_NO_VERSION,
+                VERSION_0_3,
+                EXPECTED_CQL_CROSS_TARGET);
+    }
+
+    protected void verifyMeasure(
+            @Nullable Measure measure, String measureUrl, String version, String expectedLibraryUrl) {
+
+        assertNotNull(measure, "Could not find measure with url: %s".formatted(measureUrl));
+
+        assertEquals(measureUrl, measure.getUrl());
+
+        assertEquals(version, measure.getVersion());
+
+        final List<CanonicalType> libraryUrls = measure.getLibrary();
+        assertEquals(1, libraryUrls.size());
+        final CanonicalType libraryUrl = libraryUrls.get(0);
+        assertEquals(expectedLibraryUrl, libraryUrl.asStringValue());
+    }
+
+    private void verifyLibrary(
+            @Nullable ILibraryAdapter libraryAdapter, String expectedLibraryUrl, String version, String expectedCql) {
+
+        assertNotNull(libraryAdapter, "Could not find library with url: %s".formatted(expectedLibraryUrl));
+
+        assertInstanceOf(LibraryAdapter.class, libraryAdapter);
+
+        verifyLibrary(((LibraryAdapter) libraryAdapter).get(), expectedLibraryUrl, version, expectedCql);
+    }
+
+    private void verifyLibrary(
+            @Nullable Library library, String expectedLibraryUrl, String version, String expectedCql) {
+
+        assertNotNull(library, "Could not find library with url: %s".formatted(expectedLibraryUrl));
+
+        assertEquals(expectedLibraryUrl, library.getUrl());
+
+        assertEquals(version, library.getVersion());
+
+        final List<Attachment> attachments = library.getContent();
+        assertEquals(1, attachments.size());
+        final Attachment attachment = attachments.get(0);
+        assertEquals("text/cql", attachment.getContentType());
+        final byte[] attachmentData = attachment.getData();
+        final String cql = new String(attachmentData, StandardCharsets.UTF_8);
+
+        assertEquals(expectedCql, cql);
+    }
+
+    @Nonnull
+    @Override
+    protected R5NpmPackageLoaderInMemory setup(Path... tgzPaths) {
+        return R5NpmPackageLoaderInMemory.fromNpmPackageClasspath(getClass(), tgzPaths);
+    }
+
+    @Nonnull
+    @Override
+    protected R5NpmPackageLoaderInMemory setup(List<Path> tgzPaths) {
+        return R5NpmPackageLoaderInMemory.fromNpmPackageClasspath(getClass(), tgzPaths);
+    }
+}
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