I have been using Moq for my mocking needs the last years, but after looking at FakeItEasy i wanted to give it a try.
I often want to test that a method have been called with the correct parameters, but i found no satisfactory way to do this with FakeItEasy.
I have the following code to test:
public class WizardStateEngine : IWizardStateEngine
{
private readonly IWorkflowInvoker _workflowInvoker;
private List<CustomBookmark> _history;
public WizardStateEngine(IWorkflowInvoker workflowInvoker)
{
_workflowInvoker = workflowInvoker;
}
public void Initialize(List<CustomBookmark> history)
{
_history = history;
}
public WizardStateContext Execute(Command command, WizardStateContext stateContext, CustomBookmark step)
{
Activity workflow = new MyActivity();
var input = new Dictionary<string, object>();
input["Action"] = command;
input["Context"] = stateContext;
input["BookmarkHistory"] = _history;
var output = _workflowInvoker.Invoke(workflow, input);
_history = output["BookmarkHistory"] as List<CustomBookmark>;
return output["Context"] as WizardStateContext;
}
public List<CustomBookmark> GetBookmarkHistory()
{
return _history;
}
}
I want to write some tests that verifies the input to _workflowInvoker.Invoke(). My TestInitialize method sets up the needed resources and save the input dictionary to _workflowInvoker.Invoke() as a local field _wfInput.
[TestInitialize]
public void TestInitialize()
{
_wizardStateContext = new WizardStateContext();
_workflowInvoker = A.Fake<IWorkflowInvoker>();
_wizardStateEngine = new WizardStateEngine(_workflowInvoker);
_outputContext = new WizardStateContext();
_outputHistory = new List<CustomBookmark>();
_wfOutput = new Dictionary<string, object>
{{"Context", _outputContext}, {"BookmarkHistory", _outputHistory}};
_history = new List<CustomBookmark>();
A.CallTo(() =>
_workflowInvoker.Invoke(A<Activity>.Ignored, A<Dictionary<string, object>>.Ignored))
.Invokes(x => _wfInput = x.Arguments.Get<Dictionary<string, object>>("input"))
.Returns(_wfOutput);
_wizardStateEngine.Initialize(_history);
}
After the setup i have multiple tests like this:
[TestMethod]
public void Should_invoke_with_correct_command()
{
_wizardStateEngine.Execute(Command.Start, null, null);
((Command) _wfInput["Action"]).ShouldEqual(Command.Start);
}
[TestMethod]
public void Should_invoke_with_correct_context()
{
_wizardStateEngine.Execute(Command.Start, _wizardStateContext, null);
((WizardStateContext) _wfInput["Context"]).ShouldEqual(_wizardStateContext);
}
[TestMethod]
public void Should_invoke_with_correct_history()
{
_wizardStateEngine.Execute(Command.Start, _wizardStateContext, null);
((List<CustomBookmark>) _wfInput["BookmarkHistory"]).ShouldEqual(_history);
}
I do not like the magic string "input" in the TestInitialize for getting the passed argument (or magic number). I can write the tests without the local field like this:
[TestMethod]
public void Should_invoke_with_correct_context()
{
_wizardStateEngine.Execute(Command.Start, _wizardStateContext, null);
A.CallTo(() =>
_workflowInvoker.Invoke(A<Activity>._,
A<Dictionary<string, object>>.That.Matches(
x => (WizardStateContext) x["Context"] == _wizardStateContext)))
.MustHaveHappened();
}
But i find the tests with the local field more readable.
Are there any way to setup saving of the input as a field i my test class without magic numbers or strings?
I hope the updated example in the question shows why i would like to use the local field. I am more than willing to write my tests without the local field if i can find a nice readable way to do it.