Add "final" support to SDK content tests

Author: lbussell

tests/Microsoft.DotNet.Docker.Tests/Config.cs

@@ -67,6 +67,20 @@ private static JObject LoadManifest(string manifestFile)
         public static string GetVariableValue(string variableName) =>
             GetVariableValue(variableName, (JObject)ManifestVersions.Value["variables"]);
 
+        public static bool TryGetVariableValue(string variableName, out string value)
+        {
+            var variables = (JObject)ManifestVersions.Value["variables"];
+            JToken token = variables[variableName];
+            if (token is null)
+            {
+                value = string.Empty;
+                return false;
+            }
+
+            value = ResolveVariables((string)token, variables);
+            return true;
+        }
+
         private static string GetVariableValue(string variableName, JObject variables) =>
             ResolveVariables((string)variables[variableName], variables);
 

tests/Microsoft.DotNet.Docker.Tests/SdkImageTests.cs

@@ -347,11 +347,20 @@ private static string GetSdkVersionFileLabel(string sdkBuildVersion, string dotn
                 || sdkBuildVersion.Contains("-servicing")
                 || sdkBuildVersion.Contains("-rtm");
 
-            string sdkVersionFile = isStableBranding
-                ? Config.GetVariableValue($"sdk|{dotnetVersion}|product-version")
-                : sdkBuildVersion;
+            if (isStableBranding)
+            {
+                return Config.GetVariableValue($"sdk|{dotnetVersion}|product-version");
+            }
+
+            bool useFinalVersion =
+                Config.TryGetVariableValue($"sdk|{dotnetVersion}|use-final-version", out string finalFlag)
+                && finalFlag == "true";
+            if (useFinalVersion)
+            {
+                return Config.GetVariableValue($"sdk|{dotnetVersion}|product-version") + ".final";
+            }
 
-            return sdkVersionFile;
+            return sdkBuildVersion;
         }
 
         private string GetSdkUrl(ProductImageData imageData)