单元测试多个断言

Question

I am trying to unit test a method in C# using MSTest. I am testing that the password complexity is forced by the ChangePasswordAsync method. My problem is I want to test this method with a range of parameters. Currently i have a unit test with multiple asserts to test the different parameters, is this a reasonable solution?

I know when i have used other unit testing frameworks there have been ways to test a method with different parameters. Is there an attribute I can use upon the method to achieve this? My example unit test is below:

    /// <summary>
    /// Ensures that a password must meet the password complexity of a digit and an alphanumeric, 8 digits long and one
    /// special character.
    /// </summary>
    [TestMethod]
    public void TestPasswordComplexity()
    {
        var result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "1!").Result; //Changes the password.

        Assert.IsFalse(result.Succeeded);

        result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "123456789").Result; //Changes the password.

        Assert.IsFalse(result.Succeeded);

        result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "123456789!").Result; //Changes the password.

        Assert.IsFalse(result.Succeeded);

        result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "abcdefghijk").Result; //Changes the password.

        Assert.IsFalse(result.Succeeded);

        result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", "abcdefghijK1!").Result; //Changes the password.

        Assert.IsTrue(result.Succeeded);
    }  

Or alternatively would you break each one into seperate unit tests?

Answer 1

You can add data row annotations.

[TestMethod]
[DataRow ("1!")
[DataRow ("123456789")
[DataRow ("123456789!")
...
public void TestPasswordComplexity(string pass)
{
    var result = _UserManager.ChangePasswordAsync(_TestUser.Id, "Password123!", pass).Result; //Changes the password.

    Assert.IsFalse(result.Succeeded);
}

It will run the test method with each data row passed with the pass parameter.

Create a separate method for the fifth Assert.IsTrue(result.Succeeded) case

Answer 2

Write for every test a separate unit test method with a meaning full name. So when later on the test fails you find out easily what's the problem.

You have to distinguish between different tests and different test parameters. Some of your asserts will fail because the password is for some reason to weak, some should pass.

For the case where you really need different parameters, there is the possibility to use DataSource (see http://msdn.microsoft.com/en-us/library/ms182527.aspx ) where you can add an external source as excel file for input.

Eg you could test passing passwords with the excel source.