Unit Testing - Is it bad form to have unit test calling other unit tests

Question

I have a unit test called TestMakeAValidCall(). It tests my phone app making a valid call.

I am about to write another test called TestShowCallMe

Answer 1

To offer a counter point:

I strongly believe that well designed unit test should depend on one another!

Of course, that makes sense only if the testing framework is aware of these dependencies such that it can stop running dependent test when a dependency fails. Even better, such a framework can pass the fixture from test to test, such that can build upon a growing and extending fixture instead of rebuilding it from scratch for each single test. Of course, caching is done to take care no side-effects are introduced when more than one test depends from the same example.

We implemented this idea in the JExample extension for JUnit. There is no C# port yet, though there are ports for Ruby and Smalltalk and ... the most recent release of PHPUnit picked up both our ideas: dependencies and fixture reuse.

PS: folks are also using it for Groovy.

Answer 2

"Could someone ellaborate on how the refactoring would look like in this case? – Philip Bergström Nov 28 '15 at 15:33"

I am currently doing something like this and this is what i came up with:

Notice that ProcessorType and BuildProcessors both call TestLevels

the actual content besides that fact is unimportant

its using XUnit, and Shouldly NuGet package

private static void TestLevels(ArgProcessor incomingProcessor)
{
    Action<ProcessorLevel, int> currentLevelIteration = null;
    currentLevelIteration = (currentProcessor, currentLevel) =>
    {
        currentProcessor.CurrentLevel.ShouldBeEquivalentTo(currentLevel);
        ProcessorLevel nextProcessor = currentProcessor.CurrentProcessor;
        if (nextProcessor != null)
            currentLevelIteration(nextProcessor, currentLevel + 1);
    };

    currentLevelIteration(incomingProcessor, 0);
}

[Theory]
[InlineData(typeof(Build), "Build")]
public void ProcessorType(Type ProcessorType, params string[] args)
{
    ArgProcessor newCLI = new OriWeb_CLI.ArgProcessor(args);

    IncomingArgumentsTests.TestLevels(newCLI);

    newCLI.CurrentProcessor.ShouldBeOfType(ProcessorType);
}

[Theory]
[InlineData(typeof(Build.TypeScript), "TypeScript")]
[InlineData(typeof(Build.CSharp), "CSharp")]
public void BuildProcessors(Type ProcessorType, params string[] args)
{
    List<string> newArgs = new List<string> {"Build"};
    foreach(string arg in args) newArgs.Add(arg);

    ArgProcessor newCLI = new OriWeb_CLI.ArgProcessor(newArgs.ToArray());

    IncomingArgumentsTests.TestLevels(newCLI);

    newCLI.CurrentProcessor.CurrentProcessor.ShouldBeOfType(ProcessorType);
}