Overview

TLDR, How to enable

nuget package: CommandDotNet.TestTools

.NET CLI

dotnet add package CommandDotNet.TestTools

Nuget Package Manager

Install-Package CommandDotNet.TestTools

Testing Console Apps

One of the perks of using this framework is that commands are just methods and methods are easily unit tested. Most of your tests can be unit tests, as is best-practice.

These tools enable you to provide end-to-end testing as if running the app in a console.

Note

These test tools are used to test all of the CommandDotNet features.
They are well suited to testing middleware and other extensibility components.

Testing the AppRunner

The tool provides two extension methods to execute an AppRunner in memory and collect the results.

RunInMem

public class PipedInputTests
{
    [Test]
    public void PipedInput_Should_UnionWithUserSuppliedValues()
    {
        var result = new AppRunner<App>()
            .AppendPipedInputToOperandList()
            .RunInMem("List aaa bbb", pipedInput: new[] { "ccc", "ddd" });

        result.ExitCode.Should().Be(0);
        result.OutputShouldBe(@"aaa
bbb
ccc
ddd
");
    }

    private class App
    {
        public void List(IConsole console, List<string> args) =>
            console.WriteLine(string.Join(Environment.NewLine, args));
    }
}

BDD Verify

public class PipedInputTests
{
    [Test]
    public void PipedInput_Should_UnionWithUserSuppliedValues()
    {
        new AppRunner<App>()
            .AppendPipedInputToOperandList()
            .Verify(new Scenario
            {
                When = 
                {
                    Args = "List aaa bbb",
                    PipedInput = new[] { "ccc", "ddd" } 
                },
                Then =
                {
                    Output = @"aaa
bbb
ccc
ddd
"
                }
            });
    }

    private class App
    {
        public void List(IConsole console, List<string> args) =>
            console.WriteLine(string.Join(Environment.NewLine, args));
    }
}

RunInMem will run the runner and collect results. Assertions will need to be executed after.

Verify wraps RunInMem with declarative BDD style setup and assertions.

Tip

If you're using the .UseDefaultMiddleware() method, testing with either of these will help identify behavior changes on upgrade due to new opt-in features.

Testing your application

When testing an application, use the same method to generate and configure the AppRunner for the console and tests. In this example, the GetAppRunner() method is made public so tests can verify the exact config used in the application.

public class Program
{
        static int Main(string[] args)
        {
            Debugger.AttachIfDebugDirective(args);

            return GetAppRunner().Run(args);
        }

        public static AppRunner GetAppRunner()
        {    
            new AppRunner<Git>()
                .UseDefaultMiddleware()
                .UseNameCasing(Case.KebabCase)
                .UseFluentValidation();
        }
}

[TestFixture]
public class ProgramTests
{
    [Test]
    public void Checkout_NewBranch_WithoutBranchFlag_Fails()
    {
        Program.GetAppRunner()
            .Verify(new Scenario
            {
                When = { Args = "checkout lala" },
                Then = { 
                    Output = "error: pathspec 'lala' did not match any file(s) known to git" 
                }
            });
    }

    [Test]
    public void Checkout_NewBranch_BranchFlag_Succeeds()
    {
        Program.GetAppRunner()
            .Verify(new Scenario
            {
                When = { Args = "checkout -b lala" },
                Then = { 
                    Output = "Switched to a new branch 'lala'" 
                }
            });
    }
}

Included test tools

The framework includes the following tools that can be used independently of the BDD Framework.

TestConsole

• capture output for assertions
• provide piped input
• handle ReadLine and ReadKey

TempFiles

• Creates temp files, give content and receive a file path.
• Removes created files on dispose
• Examples: ResponseFileTests

TestDependencyResolver

new AppRunner<App>()
    .UseDependencyResolver(new TestDependencyResolver { dbSvc, httpSvc })
    .VerifyScenario(scenario);

CaptureState

• appRunner.CaptureState(...) extension method that can be used to capture the point-in-time state of an object within the middleware pipeline.
• Examples: DefaultArityTests and Options_Name_Tests