MissingMethodException when Verify Method with Array of ValueTuple

[Ben-Ebsta]

To be honest, I'm not sure if you actually support this, but here is what I am trying to do:

I have a logger class that I want to mock and it has a method Fatal that I would like to verify. I am having trouble matching the method signature and I think it is because it takes an array of ValueTuples.

void Fatal(string message, params (string Name, object Value)[] attributes);

Here is what I tried:

mockLogger.Verify(x => x.Fatal(It.IsAny<string>(), It.IsAny<(string Name, object Value)[]>()), Times.Once);

This compiles, but when I run my unit test it throws the MissingMethodException exception.

[stakx]

I cannot reproduce the error you're reporting:

using Moq;

var mock = new Mock<ILogger>();
mock.Verify(m => m.Fatal(It.IsAny<string>(), It.IsAny<(string Name, object Value)[]>()), Times.Once);

public interface ILogger
{
    void Fatal(string message, params (string Name, object Value)[] attributes);
}

When run, the above program causes the following exception (as it should):

Moq.MockException:
Expected invocation on the mock once, but was 0 times: m => m.Fatal(It.IsAny<string>(), It.IsAny<(string, object)[]>())

Performed invocations:

   Mock<ILogger:1> (m):
   No invocations performed.

Please provide complete, but minimal repro code; otherwise I'm going to close this issue in a few days' time.

[Ben-Ebsta]

@stakx thanks for the quick reply. I appreciate you trying this out and the fact you couldn't reproduce is valuable information. In trying to create a minimal repo code, somehow the error disappeared for me too. I will dig a bit deeper and try and work out what exactly is causing the exception.

[Ben-Ebsta]

@stakx it turns out that the reason I was getting this error, was because the NuGet package System.ValueTuple v4.5.0 was installed and in the app.config file there was also the following:

<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.ValueTuple" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.2.0" newVersion="4.0.2.0" />
      </dependentAssembly>
      ...
    </assemblyBinding>
  </runtime>
</configuration>

After I removed the assembly binding redirect from the app.config it all worked fine. However, just to make sure I also uninstalled the NuGet package as well since I believe ValueTuples are now built-in right?

Thanks again for your help.