#12: Add tests for async stubbing and getting the MoveNext method

test/Pose.Tests/Extensions/TypeExtensionsTests.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+using FluentAssertions;
+using Pose.Extensions;
+using Xunit;
+
+namespace Pose.Tests
+{
+    public class TypeExtensionsTests
+    {
+        private static async Task<int> GetIntAsync() => await Task.FromResult(1);
+
+        [Fact]
+        public void Can_get_explicitly_implemented_MoveNext_method_on_state_machine()
+        {
+            // Arrange
+            var stateMachineType = typeof(TypeExtensionsTests).GetMethod(nameof(GetIntAsync), BindingFlags.Static | BindingFlags.NonPublic)?.GetCustomAttribute<AsyncStateMachineAttribute>()?.StateMachineType;
+
+            // Act
+            Func<MethodInfo> func = () => stateMachineType.GetExplicitlyImplementedMethod<IAsyncStateMachine>(nameof(IAsyncStateMachine.MoveNext));
+
+            // Assert
+            func.Should().NotThrow(because: "it is possible to get the MoveNext method on the state machine");
+
+            var moveNextMethod = func();
+            moveNextMethod.Should().NotBeNull(because: "the method exists");
+            moveNextMethod.ReturnType.Should().Be(typeof(void));
+
+            var parameters = moveNextMethod.GetParameters();
+            parameters.Should().BeEmpty(because: "the method does not take any parameters");
+        }
+    }
+}

test/Pose.Tests/IL/StubsTests.cs

@@ -1,7 +1,11 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
 using FluentAssertions;
+using Pose.Extensions;
 using Pose.IL;
 using Xunit;
 
@@ -87,6 +91,26 @@ public void Can_generate_stub_for_virtual_call()
             valueParameter.ParameterType.Should().Be(typeof(string), because: "the second parameter is the value to be added");
         }
 
+        private static async Task<int> GetIntAsync() => await Task.FromResult(1);
+
+        [Fact]
+        public void Can_generate_stub_for_async_virtual_call()
+        {
+            // Arrange
+            var stateMachineType = typeof(StubsTests)?.GetMethod(nameof(GetIntAsync), BindingFlags.Static | BindingFlags.NonPublic)?.GetCustomAttribute<AsyncStateMachineAttribute>()?.StateMachineType;
+            var moveNextMethod = stateMachineType.GetExplicitlyImplementedMethod<IAsyncStateMachine>(nameof(IAsyncStateMachine.MoveNext));
+
+            // Act
+            var dynamicMethod = Stubs.GenerateStubForVirtualCall(moveNextMethod);
+
+            // Assert
+            var dynamicParameters = dynamicMethod.GetParameters();
+            dynamicParameters.Should().HaveCount(1, because: "the dynamic method takes only the instance parameter");
+
+            var instanceParameter = dynamicParameters[0];
+            instanceParameter.ParameterType.Should().Be(stateMachineType, because: "the first parameter is the instance");
+        }
+
         [Fact]
         public void Can_generate_stub_for_reference_type_constructor()
         {