Add integration tests for fluent BodyReturningConstant pattern via data abstraction layer

Co-authored-by: dex3r <[email protected]>
Agent-Logs-Url: https://github.com/dex3r/EasySourceGenerators/sessions/8070e196-96aa-4613-adf2-2df1ce631bfe

Author: Copilot

EasySourceGenerators.Tests/FluentBodyReturningConstantTests.cs

@@ -0,0 +1,85 @@
+using EasySourceGenerators.Abstractions;
+
+namespace EasySourceGenerators.Tests;
+
+[TestFixture]
+public class FluentBodyReturningConstantTests
+{
+    [Test]
+    public void FluentBodyReturningConstant_ProducesExpectedRuntimeOutput()
+    {
+        TestFluentConstantClass instance = new TestFluentConstantClass();
+
+        string result = instance.GetGreeting();
+
+        Assert.That(result, Is.EqualTo("Hello from fluent API"));
+    }
+
+    [Test]
+    public void FluentBodyReturningConstant_ProducesExpectedGeneratedCode()
+    {
+        string generatedCode = GeneratedCodeTestHelper.ReadGeneratedCode("TestFluentConstantClass_GetGreeting.g.cs");
+        string expectedCode = """
+                              namespace EasySourceGenerators.Tests;
+
+                              partial class TestFluentConstantClass
+                              {
+                                  public partial string GetGreeting()
+                                  {
+                                      return "Hello from fluent API";
+                                  }
+                              }
+                              """.ReplaceLineEndings("\n").TrimEnd();
+
+        Assert.That(generatedCode, Is.EqualTo(expectedCode));
+    }
+
+    [Test]
+    public void FluentBodyReturningConstant_Int_ProducesExpectedRuntimeOutput()
+    {
+        int result = TestFluentConstantIntClass.GetMagicNumber();
+
+        Assert.That(result, Is.EqualTo(42));
+    }
+
+    [Test]
+    public void FluentBodyReturningConstant_Int_ProducesExpectedGeneratedCode()
+    {
+        string generatedCode = GeneratedCodeTestHelper.ReadGeneratedCode("TestFluentConstantIntClass_GetMagicNumber.g.cs");
+        string expectedCode = """
+                              namespace EasySourceGenerators.Tests;
+
+                              static partial class TestFluentConstantIntClass
+                              {
+                                  public static partial int GetMagicNumber()
+                                  {
+                                      return 42;
+                                  }
+                              }
+                              """.ReplaceLineEndings("\n").TrimEnd();
+
+        Assert.That(generatedCode, Is.EqualTo(expectedCode));
+    }
+}
+
+public partial class TestFluentConstantClass
+{
+    public partial string GetGreeting();
+
+    [MethodBodyGenerator(nameof(GetGreeting))]
+    static IMethodBodyGenerator GetGreeting_Generator() =>
+        Generate
+            .MethodBody().ForMethod().WithReturnType<string>().WithNoParameters()
+            .BodyReturningConstant(() => "Hello from fluent API");
+}
+
+public static partial class TestFluentConstantIntClass
+{
+    public static partial int GetMagicNumber();
+
+    [MethodBodyGenerator(nameof(GetMagicNumber))]
+    static IMethodBodyGenerator GetMagicNumber_Generator() =>
+        Generate
+            .MethodBody().ForMethod().WithReturnType<int>().WithNoParameters()
+            .BodyReturningConstant(() => 42);
+}