Allow Task-returning test methods without async keyword (#510)

Enables asynchronous tests that don't use the async state machine while
still rejecting async void methods.

Author: spanglerco

src/Adapter/MSTest.CoreAdapter/Extensions/MethodInfoExtensions.cs

@@ -114,8 +114,8 @@ internal static bool HasCorrectTimeout(this MethodInfo method)
         /// <returns>True if the method has a void/task return type..</returns>
         internal static bool IsVoidOrTaskReturnType(this MethodInfo method)
         {
-            return method.GetAsyncTypeName() == null ? ReflectHelper.MatchReturnType(method, typeof(void))
-                : ReflectHelper.MatchReturnType(method, typeof(Task));
+            return ReflectHelper.MatchReturnType(method, typeof(Task))
+                || (ReflectHelper.MatchReturnType(method, typeof(void)) && method.GetAsyncTypeName() == null);
         }
 
         /// <summary>

test/UnitTests/MSTest.CoreAdapter.Unit.Tests/Discovery/TestMethodValidatorTests.cs

@@ -134,7 +134,7 @@ public void IsValidTestMethodShouldReturnFalseForMethodsWithNonVoidReturnType()
         {
             this.SetupTestMethod();
             var methodInfo = typeof(DummyTestClass).GetMethod(
-                "MethodWithTaskReturnType",
+                "MethodWithIntReturnType",
                 BindingFlags.Instance | BindingFlags.Public);
 
             Assert.IsFalse(this.testMethodValidator.IsValidTestMethod(methodInfo, typeof(DummyTestClass), this.warnings));
@@ -151,6 +151,17 @@ public void IsValidTestMethodShouldReturnTrueForAsyncMethodsWithTaskReturnType()
             Assert.IsTrue(this.testMethodValidator.IsValidTestMethod(methodInfo, this.type, this.warnings));
         }
 
+        [TestMethod]
+        public void IsValidTestMethodShouldReturnTrueForNonAsyncMethodsWithTaskReturnType()
+        {
+            this.SetupTestMethod();
+            var methodInfo = typeof(DummyTestClass).GetMethod(
+                "MethodWithTaskReturnType",
+                BindingFlags.Instance | BindingFlags.Public);
+
+            Assert.IsTrue(this.testMethodValidator.IsValidTestMethod(methodInfo, this.type, this.warnings));
+        }
+
         [TestMethod]
         public void IsValidTestMethodShouldReturnTrueForMethodsWithVoidReturnType()
         {
@@ -201,6 +212,11 @@ public Task MethodWithTaskReturnType()
             return Task.Delay(TimeSpan.Zero);
         }
 
+        public int MethodWithIntReturnType()
+        {
+            return 0;
+        }
+
         public void MethodWithVoidReturnType()
         {
         }

test/UnitTests/MSTest.CoreAdapter.Unit.Tests/Extensions/MethodInfoExtensionsTests.cs

@@ -74,6 +74,13 @@ public void HasCorrectClassOrAssemblyInitializeSignatureShouldReturnTrueForAsync
             Assert.IsTrue(methodInfo.HasCorrectClassOrAssemblyInitializeSignature());
         }
 
+        [TestMethod]
+        public void HasCorrectClassOrAssemblyInitializeSignatureShouldReturnTrueForTestMethodsWithoutAsync()
+        {
+            var methodInfo = typeof(DummyTestClass).GetMethod("PublicStaticNonAsyncTaskMethodWithTC");
+            Assert.IsTrue(methodInfo.HasCorrectClassOrAssemblyInitializeSignature());
+        }
+
         [TestMethod]
         public void HasCorrectClassOrAssemblyInitializeSignatureShouldReturnFalseForAsyncTestMethodsWithNonTaskReturnTypes()
         {
@@ -127,6 +134,13 @@ public void HasCorrectClassOrAssemblyCleanupSignatureShouldReturnTrueForAsyncTes
             Assert.IsTrue(methodInfo.HasCorrectClassOrAssemblyCleanupSignature());
         }
 
+        [TestMethod]
+        public void HasCorrectClassOrAssemblyCleanupSignatureShouldReturnTrueForTestMethodsWithoutAsync()
+        {
+            var methodInfo = typeof(DummyTestClass).GetMethod("PublicStaticNonAsyncTaskMethod");
+            Assert.IsTrue(methodInfo.HasCorrectClassOrAssemblyCleanupSignature());
+        }
+
         [TestMethod]
         public void HasCorrectClassOrAssemblyCleanupSignatureShouldReturnFalseForAsyncTestMethodsWithNonTaskReturnTypes()
         {
@@ -180,6 +194,13 @@ public void HasCorrectTestInitializeOrCleanupSignatureShouldReturnTrueForAsyncTe
             Assert.IsTrue(methodInfo.HasCorrectTestInitializeOrCleanupSignature());
         }
 
+        [TestMethod]
+        public void HasCorrectTestInitializeOrCleanupSignatureShouldReturnTrueForTestMethodsWithoutAsync()
+        {
+            var methodInfo = typeof(DummyTestClass).GetMethod("PublicNonAsyncTaskMethod");
+            Assert.IsTrue(methodInfo.HasCorrectTestInitializeOrCleanupSignature());
+        }
+
         [TestMethod]
         public void HasCorrectTestInitializeOrCleanupSignatureShouldReturnFalseForAsyncTestMethodsWithNonTaskReturnTypes()
         {
@@ -247,6 +268,13 @@ public void HasCorrectTestMethodSignatureShouldReturnTrueForAsyncTestMethods()
             Assert.IsTrue(methodInfo.HasCorrectTestMethodSignature(false));
         }
 
+        [TestMethod]
+        public void HasCorrectTestMethodSignatureShouldReturnTrueForTaskTestMethodsWithoutAsync()
+        {
+            var methodInfo = typeof(DummyTestClass).GetMethod("PublicNonAsyncTaskMethod");
+            Assert.IsTrue(methodInfo.HasCorrectTestMethodSignature(false));
+        }
+
         [TestMethod]
         public void HasCorrectTestMethodSignatureShouldReturnFalseForAsyncTestMethodsWithNonTaskReturnTypes()
         {
@@ -297,6 +325,13 @@ public void IsVoidOrTaskReturnTypeShouldReturnTrueForAsyncTaskMethods()
             Assert.IsTrue(methodInfo.IsVoidOrTaskReturnType());
         }
 
+        [TestMethod]
+        public void IsVoidOrTaskReturnTypeShouldReturnTrueForTaskMethodsWithoutAsync()
+        {
+            var methodInfo = typeof(DummyTestClass).GetMethod("PublicNonAsyncTaskMethod");
+            Assert.IsTrue(methodInfo.IsVoidOrTaskReturnType());
+        }
+
         [TestMethod]
         public void IsVoidOrTaskReturnTypeShouldReturnFalseForNonVoidMethods()
         {
@@ -453,6 +488,11 @@ public static async Task PublicStaticAsyncTaskMethodWithTC(UTFExtension.TestCont
                 await Task.FromResult(true);
             }
 
+            public static Task PublicStaticNonAsyncTaskMethodWithTC(UTFExtension.TestContext tc)
+            {
+                return Task.FromResult(true);
+            }
+
             public static async void PublicStaticAsyncVoidMethodWithTC(UTFExtension.TestContext tc)
             {
                 await Task.FromResult(true);
@@ -473,6 +513,11 @@ public static async void PublicStaticAsyncVoidMethod()
                 await Task.FromResult(true);
             }
 
+            public static Task PublicStaticNonAsyncTaskMethod()
+            {
+                return Task.FromResult(true);
+            }
+
             public void PublicMethod()
             {
             }
@@ -502,6 +547,11 @@ public async void PublicAsyncVoidMethod()
                 await Task.FromResult(true);
             }
 
+            public Task PublicNonAsyncTaskMethod()
+            {
+                return Task.FromResult(true);
+            }
+
             [UTF.Timeout(-11)]
             public void PublicMethodWithInvalidTimeout()
             {