public void Create_InputStorageInstance_CalledAddMethodOfDBSetWithStorageInstance() { // Arrange DbContextOptions opt = new DbContextOptionsBuilder <ProjectContext>() .Options; var mockContext = new Mock <ProjectContext>(opt); var mockDbSet = new Mock <DbSet <Storage> >(); mockContext .Setup(context => context.Set <Storage>( )) .Returns(mockDbSet.Object); var repository = new TestStorageRepository(mockContext.Object); Storage expectedStorage = new Mock <Storage>().Object; //Act repository.Create(expectedStorage); // Assert mockDbSet.Verify( dbSet => dbSet.Add( expectedStorage ), Times.Once()); }