public void AddRefreshTokenCheckWhenRefreshTokenNotExist_Test() { _refreshTokenRepositoryMock.Setup(repo => repo.GetAsync(It.IsAny <System.Linq.Expressions.Expression <Func <RefreshTokens, bool> > >())).Returns(async() => { return(null); }); _refreshTokenRepositoryMock.Setup(repo => repo.InsertAsync(refreshTokenInitialize)).Returns(async() => { return(refreshTokenInitialize); }); var result = _refreshTokenService.AddRefreshTokenAsync(RefreshToken, UserId, DaysToExpire); Assert.IsTrue(result.IsCompleted); }