public void SessionStateServiceDeleteReturnsSuccess() { // arrange const bool expectedResult = true; var documentService = A.Fake <IDocumentService <SessionStateModel <TestSessionStateModel> > >(); A.CallTo(() => documentService.DeleteAsync(A <Guid> .Ignored)).Returns(expectedResult); var sessionStateService = new SessionStateService <TestSessionStateModel>(documentService); // act var result = sessionStateService.DeleteAsync(Guid.NewGuid()).Result; // assert A.CallTo(() => documentService.DeleteAsync(A <Guid> .Ignored)).MustHaveHappenedOnceExactly(); A.Equals(result, expectedResult); }