I have a message box service that hase the following interface
public interface IMessageBoxService
{
DialogResult DisplayMessage(IWin32Window owner, string text,
string caption, MessageBoxButtons buttons, MessageBoxIcon icon,
MessageBoxDefaultButton defaultButton = MessageBoxDefaultButton.Button1);
}
It essentally wraps the System.Windows.Forms
message box and allows me to Mock parts of my code that show a message box. Now I have a search service for text documents that shows a "No more occurrances located" message if the search looped. I want to write a unit test for the functionality of this class, the FindNextMethod
is
public TextRange FindNext(IDocumentManager documentManager, IMessageBoxService messageBoxService,
TextEditorControl textEditor, SearchOptions options, FindAllResultSet findAllResults = null)
{
...
if (options.SearchType == SearchType.CurrentDocument)
{
Helpers.SelectResult(textEditor, range);
if (persistLastSearchLooped)
{
string message = MessageStrings.TextEditor_NoMoreOccurrances;
messageBoxService.DisplayMessage(textEditor.Parent, message,
Constants.Trademark, MessageBoxButtons.OK, MessageBoxIcon.Information); <- Throws here.
Log.Trace($"TextEditorSearchProvider.FindNext(): {message}");
lastSearchLooped = false;
}
}
...
}
My test is
[TestMethod]
public void FindInCurrentForwards()
{
// Mock the IMessageBoxService.
int dialogShownCounter = 0;
var mock = new Mock<IMessageBoxService>();
mock.Setup(m => m.DisplayMessage(It.IsAny<IWin32Window>(), It.IsAny<string>(), It.IsAny<string>(),
It.IsAny<MessageBoxButtons>(), It.IsAny<MessageBoxIcon>(), It.IsAny<MessageBoxDefaultButton>()))
.Returns(DialogResult.OK)
.Callback<DialogResult>(r =>
{
Trace.WriteLine($"MockMessageBoxService {r.ToString()}");
dialogShownCounter++;
});
// Start the forward search through the first document.
var options = new SearchOptions()
{
SearchText = "SomeText",
SearchType = SearchType.CurrentDocument,
MatchCase = false,
MatchWholeWord = false,
SearchForwards = false
};
var searchProvider = new TextEditorSearchProvider();
var textEditor = ((TextEditorView)documentManager.GetActiveDocument().View).TextEditor;
TextRange range = null;
for (int i = 0; i < occurances + 1; ++i)
range = searchProvider.FindNext(documentManager, mock.Object, textEditor, options);
// We expect the text to be found and the dialog to be displayed once.
Assert.IsNotNull(range);
Assert.AreEqual(1, dialogShownCounter);
}
However I am getting an
System.Reflection.TargetParameterCountException Parameter count mismatch.
I have seen this question and I seem to be doing as the answer suggest and supplying the optional parameter but I still get the exception, why?
I have seen an answer here suggesting I have to use .Result
with the correct parameter count, so I tried
mock.Setup(m => m.DisplayMessage(It.IsAny<IWin32Window>(), It.IsAny<string>(), It.IsAny<string>(),
It.IsAny<MessageBoxButtons>(), It.IsAny<MessageBoxIcon>(), It.IsAny<MessageBoxDefaultButton>()))
.Returns((IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon,
MessageBoxDefaultButton defaultButton) => DialogResult.OK)
.Callback<DialogResult>(r =>
{
Trace.WriteLine($"MockMessageBoxService {r.ToString()}");
dialogShownCounter++;
});
Thanks for your time.
The TargetParameterCountException is thrown because your callback registration is only registered with one parameter.
The Callback cannot accept the value returned by Returns. It still has to match the mocked method signature.