public void Check_That_Right_Method_Was_Called_Inside_IsUserNameAvailable_Action()
{
// Arrange
var mockUserService = new Mock <IUserService>();
mockUserService.Setup(m => m.UserExists(It.IsAny <string>()))
.Returns(false);
ValidationController validationController = GetValidationController(mockUserService: mockUserService);
const string userName = "******";
// Act
validationController.IsUserNameAvailable(userName);
// Assert
mockUserService.Verify(m => m.UserExists(userName));
}