Fix optional request body to wrap Content-Type header in null check

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/RestClientProviders/RestClientProviderTests.cs

@@ -1655,8 +1655,6 @@ public void TestApiVersionParameterReinjectedInCreateNextRequestMethod()
         [Test]
         public void ContentTypeHeaderWrappedInNullCheckWhenContentIsOptional()
         {
-            // Test that when there's an optional body parameter with a Content-Type header,
-            // the Content-Type header setting is wrapped in a null check for the content parameter
             var contentTypeParam = InputFactory.HeaderParameter(
                 "Content-Type",
                 InputFactory.Literal.String("application/json"),
@@ -1671,37 +1669,21 @@ public void ContentTypeHeaderWrappedInNullCheckWhenContentIsOptional()
                 "TestOperation",
                 requestMediaTypes: ["application/json"],
                 parameters: [contentTypeParam, bodyParam]);
-            var inputServiceMethod = InputFactory.BasicServiceMethod("Test", operation);
-            var inputClient = InputFactory.Client("TestClient", methods: [inputServiceMethod]);
-            MockHelpers.LoadMockGenerator(clients: () => [inputClient]);
-
-            var client = ScmCodeModelGenerator.Instance.TypeFactory.CreateClient(inputClient);
-            Assert.IsNotNull(client);
-
-            var restClient = client!.RestClient;
-            Assert.IsNotNull(restClient);
-
-            var createMethod = restClient.Methods.FirstOrDefault(m => m.Signature.Name == "CreateTestOperationRequest");
-            Assert.IsNotNull(createMethod, "CreateTestOperationRequest method not found");
+            var inputClient = InputFactory.Client(
+                "TestClient",
+                methods: [InputFactory.BasicServiceMethod("Test", operation)]);
 
-            var statements = createMethod!.BodyStatements as MethodBodyStatements;
-            Assert.IsNotNull(statements);
+            var clientProvider = new ClientProvider(inputClient);
+            var restClientProvider = new MockClientProvider(inputClient, clientProvider);
 
-            var expectedStatement = @"if ((content != null))
-{
-    request.Headers.Set(""Content-Type"", ""application/json"");
-}
-";
-            var statementsString = string.Join("\n", statements!.Select(s => s.ToDisplayString()));
-            Assert.IsTrue(statements!.Any(s => s.ToDisplayString() == expectedStatement),
-                $"Expected to find statement:\n{expectedStatement}\nBut got statements:\n{statementsString}");
+            var writer = new TypeProviderWriter(restClientProvider);
+            var file = writer.Write();
+            Assert.AreEqual(Helpers.GetExpectedFromFile(), file.Content);
         }
 
         [Test]
         public void ContentTypeHeaderNotWrappedInNullCheckWhenContentIsRequired()
         {
-            // Test that when there's a required body parameter with a Content-Type header,
-            // the Content-Type header setting is NOT wrapped in a null check
             var contentTypeParam = InputFactory.HeaderParameter(
                 "Content-Type",
                 InputFactory.Literal.String("application/json"),
@@ -1716,32 +1698,16 @@ public void ContentTypeHeaderNotWrappedInNullCheckWhenContentIsRequired()
                 "TestOperation",
                 requestMediaTypes: ["application/json"],
                 parameters: [contentTypeParam, bodyParam]);
-            var inputServiceMethod = InputFactory.BasicServiceMethod("Test", operation);
-            var inputClient = InputFactory.Client("TestClient", methods: [inputServiceMethod]);
-            MockHelpers.LoadMockGenerator(clients: () => [inputClient]);
-
-            var client = ScmCodeModelGenerator.Instance.TypeFactory.CreateClient(inputClient);
-            Assert.IsNotNull(client);
-
-            var restClient = client!.RestClient;
-            Assert.IsNotNull(restClient);
-
-            var createMethod = restClient.Methods.FirstOrDefault(m => m.Signature.Name == "CreateTestOperationRequest");
-            Assert.IsNotNull(createMethod, "CreateTestOperationRequest method not found");
+            var inputClient = InputFactory.Client(
+                "TestClient",
+                methods: [InputFactory.BasicServiceMethod("Test", operation)]);
 
-            var statements = createMethod!.BodyStatements as MethodBodyStatements;
-            Assert.IsNotNull(statements);
+            var clientProvider = new ClientProvider(inputClient);
+            var restClientProvider = new MockClientProvider(inputClient, clientProvider);
 
-            // Verify there's no if statement wrapping the Content-Type header
-            var wrappedStatement = @"if ((content != null))
-{
-    request.Headers.Set(""Content-Type"", ""application/json"");
-}
-";
-            var statementsString = string.Join("\n", statements!.Select(s => s.ToDisplayString()));
-            var hasIfWrappedContentType = statements!.Any(s => s.ToDisplayString().Contains(wrappedStatement));
-            Assert.IsFalse(hasIfWrappedContentType,
-                $"Content-Type should NOT be wrapped in an if statement for required content, but found:\n{statementsString}");
+            var writer = new TypeProviderWriter(restClientProvider);
+            var file = writer.Write();
+            Assert.AreEqual(Helpers.GetExpectedFromFile(), file.Content);
         }
 
         [Test]

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/RestClientProviders/TestData/RestClientProviderTests/ContentTypeHeaderNotWrappedInNullCheckWhenContentIsRequired.cs

@@ -0,0 +1,24 @@
+// <auto-generated/>
+
+#nullable disable
+
+using System.ClientModel;
+using System.ClientModel.Primitives;
+
+namespace Sample
+{
+    public partial class TestClient
+    {
+        internal global::System.ClientModel.Primitives.PipelineMessage CreateTestOperationRequest(global::System.ClientModel.BinaryContent content, global::System.ClientModel.Primitives.RequestOptions options)
+        {
+            global::Sample.ClientUriBuilder uri = new global::Sample.ClientUriBuilder();
+            uri.Reset(_endpoint);
+            global::System.ClientModel.Primitives.PipelineMessage message = Pipeline.CreateMessage(uri.ToUri(), "GET", PipelineMessageClassifier200);
+            global::System.ClientModel.Primitives.PipelineRequest request = message.Request;
+            request.Headers.Set("Content-Type", "application/json");
+            request.Content = content;
+            message.Apply(options);
+            return message;
+        }
+    }
+}

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/RestClientProviders/TestData/RestClientProviderTests/ContentTypeHeaderWrappedInNullCheckWhenContentIsOptional.cs

@@ -0,0 +1,27 @@
+// <auto-generated/>
+
+#nullable disable
+
+using System.ClientModel;
+using System.ClientModel.Primitives;
+
+namespace Sample
+{
+    public partial class TestClient
+    {
+        internal global::System.ClientModel.Primitives.PipelineMessage CreateTestOperationRequest(global::System.ClientModel.BinaryContent content, global::System.ClientModel.Primitives.RequestOptions options)
+        {
+            global::Sample.ClientUriBuilder uri = new global::Sample.ClientUriBuilder();
+            uri.Reset(_endpoint);
+            global::System.ClientModel.Primitives.PipelineMessage message = Pipeline.CreateMessage(uri.ToUri(), "GET", PipelineMessageClassifier200);
+            global::System.ClientModel.Primitives.PipelineRequest request = message.Request;
+            if ((content != null))
+            {
+                request.Headers.Set("Content-Type", "application/json");
+            }
+            request.Content = content;
+            message.Apply(options);
+            return message;
+        }
+    }
+}