Add bare bone test for migration to 154 to 155

Author: mokagio

Tests/WordPressDataTests/MigrationTests.swift

@@ -0,0 +1,35 @@
+import CoreData
+import Testing
+@testable import WordPressData
+
+struct MigrationTests {
+
+    // See https://github.com/wordpress-mobile/WordPress-iOS/pull/24494#discussion_r2057152526
+    @Test("Verify migration from version 154 (latest version before extraction to framework) to 155 (first version in framework with module modifications) works.")
+    func migrate154to155() throws {
+        let storeURL = FileManager.default.temporaryDirectory.appendingPathComponent("Migration154to155.sqlite")
+
+        let contextManager154 = ContextManager(
+            modelName: "WordPress 154",
+            store: storeURL
+        )
+        let context154 = contextManager154.newDerivedContext()
+        let blog = BlogBuilder(context154)
+            .build()
+        contextManager154.saveContextAndWait(context154)
+
+        // Create a context manager for the 155 model, it will run the migration automatically
+        let contextManager155 = ContextManager(
+            modelName: "WordPress 155",
+            store: storeURL
+        )
+
+        // Check the blog is still there, just to exercise the model...
+        let context155 = contextManager155.newDerivedContext()
+        let request = Blog.fetchRequest()
+        request.predicate = NSPredicate(format: "url == %@", blog.url!)
+        let results = try context155.fetch(request)
+        #expect(results.count == 1)
+        #expect((results.first as? Blog)?.url == blog.url)
+    }
+}