Fixed error with reflection on integration test configure builder attributes, so integration tests can be created outside of the Umbraco integration test project (#19077)

* Fixed error with reflection on integration test configure builder attributes, so integration tests can be created outside of the Umbraco integration test project.

* Fix nullability

---------

Co-authored-by: mole <[email protected]>

Author: AndyButland

tests/Umbraco.Tests.Integration/Testing/UmbracoIntegrationTest.cs

@@ -189,25 +189,48 @@ protected void ConfigureServices(IServiceCollection services)
 
     private void ExecuteBuilderAttributes(IUmbracoBuilder builder)
     {
-        // todo better errors
+        Type? testClassType = GetTestClassType()
+            ?? throw new Exception($"Could not find test class for {TestContext.CurrentContext.Test.FullName} in order to execute builder attributes.");
 
-        // execute builder attributes defined on method
-        foreach (ConfigureBuilderAttribute builderAttribute in Type.GetType(TestContext.CurrentContext.Test.ClassName)
-                     .GetMethods().First(m => m.Name == TestContext.CurrentContext.Test.MethodName)
-                     .GetCustomAttributes(typeof(ConfigureBuilderAttribute), true))
+        // Execute builder attributes defined on method.
+        foreach (ConfigureBuilderAttribute builderAttribute in GetConfigureBuilderAttributes<ConfigureBuilderAttribute>(testClassType))
         {
             builderAttribute.Execute(builder);
         }
 
-        // execute builder attributes defined on method with param value passtrough from testcase
-        foreach (ConfigureBuilderTestCaseAttribute builderAttribute in Type.GetType(TestContext.CurrentContext.Test.ClassName)
-                     .GetMethods().First(m => m.Name == TestContext.CurrentContext.Test.MethodName)
-                     .GetCustomAttributes(typeof(ConfigureBuilderTestCaseAttribute), true))
+        // Execute builder attributes defined on method with param value pass through from test case.
+        foreach (ConfigureBuilderTestCaseAttribute builderAttribute in GetConfigureBuilderAttributes<ConfigureBuilderTestCaseAttribute>(testClassType))
         {
             builderAttribute.Execute(builder);
         }
     }
 
+    private static Type? GetTestClassType()
+    {
+        string testClassName = TestContext.CurrentContext.Test.ClassName;
+
+        // Try resolving the type name directly (which will work for tests in this assembly).
+        Type testClass = Type.GetType(testClassName);
+        if (testClass is not null)
+        {
+            return testClass;
+        }
+
+        // Try scanning the loaded assemblies to see if we can find the class by full name. This will be necessary
+        // for integration test projects using the base classess provided by Umbraco.
+        var assemblies = AppDomain.CurrentDomain.GetAssemblies();
+        return assemblies
+            .SelectMany(a => a.GetTypes().Where(t => t.FullName == testClassName))
+            .FirstOrDefault();
+    }
+
+    private static IEnumerable<TAttribute> GetConfigureBuilderAttributes<TAttribute>(Type testClassType)
+        where TAttribute : Attribute =>
+        testClassType
+            .GetMethods().First(m => m.Name == TestContext.CurrentContext.Test.MethodName)
+            .GetCustomAttributes(typeof(TAttribute), true)
+            .Cast<TAttribute>();
+
     /// <summary>
     ///     Hook for altering UmbracoBuilder setup
     /// </summary>