TestCaptures

Warning

TestCaptures have been obsoleted. Use the CommandContext extension methods GetCommandInvocation and GetInterceptorInvocation<TInterceptorClass> to access the IInvocation.ParameterValues. See Testing Middleware for details.

TestCaptures are used to test middleware components. They should not be used to test your command methods since they require adding TestCaptures as a property to the class defining the commands to test.

Let's start with an example

public class FlagTests
{
    [Fact]
    public void ClubbedOptionsAreRecognized()
    {
        new AppRunner<FlagApp>()
            .Verify(new Scenario
            {
                When = { Args = "club -ab" },
                Then =
                {
                    Captured = { new ClubResult(true, true) }
                }
            });
    }

    private class FlagApp
    {
        // will be injected by the test framework
        private TestCaptures TestCaptures { get; set; }

        public int Club(
            [Option] bool a,
            [Option] bool b)
        {
            TestCaptures.Capture(new ClubResult(a, b));
        }
    }

    public class ClubResult
    {
        public bool A { get; }
        public bool B { get; }

        public ClubResult(bool a, bool b)
        {
            A = a;
            B = b;
        }
    }
}

Add TestCaptures as a property to the command class and it will be automatically injected by the test framework.

TestCaptures is a wrapper for a dictionary keyed by typed. Only one instance of any type can be captured. Classes like ClubResult are useful for capturing the content from multiple arguments. When used with BDD Verify the types must match exactly. Inheritance is not checked.

This is useful for testing middleware and other extensibility mechanisms that can populate or modify arguments.

TestCaptures are also added to the CommandContext.Services so you could add middelware for tests to capture values in a more elegant way. If you improve on our patterns, please let us know and submit a PR so we can include it in the tooling.