public async Task Should_Call_ExistAsyncMethod()
{
//Arrange
const string email = "*****@*****.**";
const string password = "******";
_manager = new UserLoginManager(_mapperMock.Object, _repositoryMock.Object);
//Act
var result = await _manager.ExistsAsync(email, password);
//Assert
_repositoryMock.Verify(x => x.ExistsAsync(email, password), Times.Once);
}