Add tests for Moq compatibility with F# events

There are two old Google Code issues which were resolved with commit
44070a9, however no documentation or unit tests were ever added for
these issues:

 * Moq fails to mock events defined in F#:
   https://code.google.com/archive/p/moq/issues/238

 * Can't raise events on mocked Interop interfaces:
   https://code.google.com/archive/p/moq/issues/226

This commit adds unit tests for the first of these two issues by add-
ing an F# test project to the solution, which allows us to define F#
types for use in unit tests.

.editorconfig

@@ -12,7 +12,7 @@ end_of_line = CRLF
 indent_style = tab
 indent_size = 4
 
-[*.{sln,proj,csproj,vbproj,props,targets,xml,xdoc,resx,config,nuspec}]
+[*.{sln,proj,csproj,fsproj,vbproj,props,targets,xml,xdoc,resx,config,nuspec}]
 indent_style = tab
 indent_size = 2
 

Moq.sln

@@ -18,6 +18,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Moq.Tests", "tests\Moq.Test
 EndProject
 Project("{778DAE3C-4631-46EA-AA77-85C1314464D9}") = "Moq.Tests.VisualBasic", "tests\Moq.Tests.VisualBasic\Moq.Tests.VisualBasic.vbproj", "{840A8B2E-3D4B-4521-A61A-0291562CDC8B}"
 EndProject
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "Moq.Tests.FSharpTypes", "tests\Moq.Tests.FSharpTypes\Moq.Tests.FSharpTypes.fsproj", "{2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}"
+EndProject
 Global
  GlobalSection(SolutionConfigurationPlatforms) = preSolution
  Debug|Any CPU = Debug|Any CPU
@@ -50,6 +52,14 @@ Global
  {840A8B2E-3D4B-4521-A61A-0291562CDC8B}.Release|Any CPU.Build.0 = Release|Any CPU
  {840A8B2E-3D4B-4521-A61A-0291562CDC8B}.Release|x86.ActiveCfg = Release|Any CPU
  {840A8B2E-3D4B-4521-A61A-0291562CDC8B}.Release|x86.Build.0 = Release|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Debug|x86.ActiveCfg = Debug|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Debug|x86.Build.0 = Debug|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Release|Any CPU.Build.0 = Release|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Release|x86.ActiveCfg = Release|Any CPU
+ {2D9EE4E0-8433-4F9C-A330-C4D74B956E0B}.Release|x86.Build.0 = Release|Any CPU
  EndGlobalSection
  GlobalSection(SolutionProperties) = preSolution
  HideSolutionNode = FALSE

src/Moq/Extensions.cs

@@ -62,6 +62,20 @@ public static bool IsPropertySetter(this MethodInfo method)
  return method.Name.StartsWith("set_", StringComparison.Ordinal);
  }
 
+ // NOTE: The following two methods used to first check whether `method.IsSpecialName` was set
+ // as a quick guard against non-event accessor methods. This was removed in commit 44070a90
+ // to "increase compatibility with F# and COM". More specifically:
+ //
+ // 1. COM does not really have events. Some COM interop assemblies define events, but do not
+ // mark those with the IL `specialname` flag. See:
+ // - https://code.google.com/archive/p/moq/issues/226
+ // - the `Microsoft.Office.Interop.Word.ApplicationEvents4_Event` interface in Office PIA
+ //
+ // 2. F# does not mark abstract events' accessors with the IL `specialname` flag. See:
+ // - https:/Microsoft/visualfsharp/issues/5834
+ // - https://code.google.com/archive/p/moq/issues/238
+ // - the unit tests in `FSharpCompatibilityFixture`
+
  public static bool LooksLikeEventAttach(this MethodInfo method)
  {
  return method.Name.StartsWith("add_", StringComparison.Ordinal);

tests/Moq.Tests.FSharpTypes/HasAbstractActionEvent.fs

@@ -0,0 +1,11 @@
+// Copyright (c) 2007, Clarius Consulting, Manas Technology Solutions, InSTEDD.
+// All rights reserved. Licensed under the BSD 3-Clause License; see License.txt.
+
+namespace Moq.Tests.FSharpTypes
+
+open System;
+
+[<AbstractClass>]
+type HasAbstractActionEvent =
+ [<CLIEvent>]
+ abstract member Event: IDelegateEvent<Action>

tests/Moq.Tests.FSharpTypes/HasAbstractEventHandlerEvent.fs

@@ -0,0 +1,11 @@
+// Copyright (c) 2007, Clarius Consulting, Manas Technology Solutions, InSTEDD.
+// All rights reserved. Licensed under the BSD 3-Clause License; see License.txt.
+
+namespace Moq.Tests.FSharpTypes
+
+open System;
+
+[<AbstractClass>]
+type HasAbstractEventHandlerEvent =
+ [<CLIEvent>]
+ abstract member Event: IEvent<EventHandler, EventArgs>

tests/Moq.Tests.FSharpTypes/HasActionEvent.fs

@@ -0,0 +1,12 @@
+// Copyright (c) 2007, Clarius Consulting, Manas Technology Solutions, InSTEDD.
+// All rights reserved. Licensed under the BSD 3-Clause License; see License.txt.
+
+namespace Moq.Tests.FSharpTypes
+
+open System;
+
+type HasActionEvent() =
+ let event = new DelegateEvent<Action>();
+
+ [<CLIEvent>]
+ member this.Event = event.Publish

tests/Moq.Tests.FSharpTypes/IHasActionEvent.fs

@@ -0,0 +1,10 @@
+// Copyright (c) 2007, Clarius Consulting, Manas Technology Solutions, InSTEDD.
+// All rights reserved. Licensed under the BSD 3-Clause License; see License.txt.
+
+namespace Moq.Tests.FSharpTypes
+
+open System;
+
+type IHasActionEvent =
+ [<CLIEvent>]
+ abstract member Event: IDelegateEvent<Action>

tests/Moq.Tests.FSharpTypes/IHasEventHandlerEvent.fs

@@ -0,0 +1,10 @@
+// Copyright (c) 2007, Clarius Consulting, Manas Technology Solutions, InSTEDD.
+// All rights reserved. Licensed under the BSD 3-Clause License; see License.txt.
+
+namespace Moq.Tests.FSharpTypes
+
+open System;
+
+type IHasEventHandlerEvent =
+ [<CLIEvent>]
+ abstract member Event: IEvent<EventHandler, EventArgs>

tests/Moq.Tests.FSharpTypes/Moq.Tests.FSharpTypes.fsproj

@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+ <Import Project="$(BuildDirectory)AssemblyInfo.props" />
+ <Import Project="$(BuildDirectory)SignAssembly.props" />
+
+ <PropertyGroup>
+ <TargetFrameworks>net46;netcoreapp2.0</TargetFrameworks>
+ <DebugSymbols>True</DebugSymbols>
+ <DebugType>full</DebugType>
+ <IsPackable>False</IsPackable>
+ </PropertyGroup>
+
+ <ItemGroup>
+ <Compile Include="HasAbstractActionEvent.fs" />
+ <Compile Include="HasAbstractEventHandlerEvent.fs" />
+ <Compile Include="HasActionEvent.fs" />
+ <Compile Include="IHasActionEvent.fs" />
+ <Compile Include="IHasEventHandlerEvent.fs" />
+ </ItemGroup>
+
+ <Target Name="Test" DependsOnTargets="Build" />
+
+</Project>

tests/Moq.Tests/FSharpCompatibilityFixture.cs

@@ -0,0 +1,81 @@
+// Copyright (c) 2007, Clarius Consulting, Manas Technology Solutions, InSTEDD.
+// All rights reserved. Licensed under the BSD 3-Clause License; see License.txt.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+
+using Moq.Tests.FSharpTypes;
+
+using Xunit;
+
+namespace Moq.Tests
+{
+ public class FSharpCompatibilityFixture
+ {
+ public static IEnumerable<object[]> AbstractFSharpEvents
+ {
+ get
+ {
+ yield return new object[] { typeof(HasAbstractActionEvent).GetEvent(nameof(HasAbstractActionEvent.Event)) };
+ yield return new object[] { typeof(HasAbstractEventHandlerEvent).GetEvent(nameof(HasAbstractEventHandlerEvent.Event)) };
+ yield return new object[] { typeof(IHasActionEvent).GetEvent(nameof(IHasActionEvent.Event)) };
+ yield return new object[] { typeof(IHasEventHandlerEvent).GetEvent(nameof(IHasEventHandlerEvent.Event)) };
+ }
+ }
+
+ public static IEnumerable<object[]> NonAbstractFSharpEvents
+ {
+ get
+ {
+ yield return new object[] { typeof(HasActionEvent).GetEvent(nameof(HasActionEvent.Event)) };
+ }
+ }
+
+ [Theory(Skip = "See https:/Microsoft/visualfsharp/issues/5834.")]
+ [MemberData(nameof(AbstractFSharpEvents))]
+ public void Abstract_FSharp_event_has_accessors_marked_as_specialname(EventInfo @event)
+ {
+ Assert.All(@event.GetAccessors(), accessor => Assert.True(accessor.IsAbstract));
+ Assert.All(@event.GetAccessors(), accessor => Assert.True(accessor.IsSpecialName, "Accessor not marked as `specialname`."));
+ }
+
+ [Theory]
+ [MemberData(nameof(NonAbstractFSharpEvents))]
+ public void Non_abstract_FSharp_event_has_accessors_marked_as_specialname(EventInfo @event)
+ {
+ Assert.All(@event.GetAccessors(), accessor => Assert.False(accessor.IsAbstract));
+ Assert.All(@event.GetAccessors(), accessor => Assert.True(accessor.IsSpecialName, "Accessor not marked as `specialname`."));
+ }
+
+ [Fact]
+ public void Can_subscribe_to_and_raise_abstract_FSharp_event()
+ {
+ var mock = new Mock<IHasEventHandlerEvent>();
+ var eventRaiseCount = 0;
+ EventHandler handler = (sender, e) => ++eventRaiseCount;
+
+ mock.Object.Event += handler;
+ mock.Raise(x => x.Event += null, EventArgs.Empty);
+
+ Assert.Equal(1, eventRaiseCount);
+ }
+
+ [Fact]
+ public void Can_unsubscribe_from_FSharp_event()
+ {
+ var mock = new Mock<IHasEventHandlerEvent>();
+ var eventRaiseCount = 0;
+ EventHandler handler = (sender, e) => ++eventRaiseCount;
+
+ mock.Object.Event += handler;
+ mock.Raise(x => x.Event += null, EventArgs.Empty);
+
+ mock.Object.Event -= handler;
+ mock.Raise(x => x.Event += null, EventArgs.Empty);
+
+ Assert.Equal(1, eventRaiseCount);
+ }
+ }
+}

tests/Moq.Tests/Moq.Tests.csproj

@@ -25,6 +25,7 @@
  <PackageReference Include="Castle.Core" Version="4.3.1" />
  <PackageReference Include="System.ValueTuple" Version="4.4.0" />
  <ProjectReference Include="..\..\src\Moq\Moq.csproj" />
+ <ProjectReference Include="..\Moq.Tests.FSharpTypes\Moq.Tests.FSharpTypes.fsproj" />
  </ItemGroup>
  <ItemGroup Condition=" '$(TargetFramework)' == 'net46' ">
  <PackageReference Include="EntityFramework" Version="6.2.0" />

tests/Moq.Tests/ReflectionExtensions.cs

@@ -0,0 +1,17 @@
+// Copyright (c) 2007, Clarius Consulting, Manas Technology Solutions, InSTEDD.
+// All rights reserved. Licensed under the BSD 3-Clause License; see License.txt.
+
+using System.Collections.Generic;
+using System.Reflection;
+
+namespace Moq.Tests
+{
+ public static class ReflectionExtensions
+ {
+ public static IEnumerable<MethodInfo> GetAccessors(this EventInfo @event, bool nonPublic = false)
+ {
+ yield return @event.GetAddMethod(nonPublic);
+ yield return @event.GetRemoveMethod(nonPublic);
+ }
+ }
+}