Add mutation for conditional (ternary) operator

Is your feature request related to a problem? Please describe. I have some code that prefixes a string conditionally:

val = val.Contains(prefix)
       ? val
       : $"{prefix}{val}";

I have a test that checks that some strings without that prefix get prefixed, but I do not have any test that checks whether already prefixed strings also get that prefix added. Stryker didn’t find that issue as I expected it to.

Describe the solution you’d like I propose adding two mutations for the conditional (ternary) operator: Original: a ? b : c Mutation 1: b Mutation 2: c

Describe alternatives you’ve considered I can’t think of any.

Additional context None.

[psfinaki]

Cool stuff!

It took me a while to understand the missing piece here so here is the mutated code that Stryker wouldn’t flag:

  private const string crap = "crap";

  public static string AddImagePrefix(string logo)
  {
      logo = logo.Contains("data:image/jpg;base64,")
          ? crap
          : $"data:image/jpg;base64,{logo}";

      return logo;
  }

Missing tests would be

[Test]
[TestCase("data:image/jpg;base64,")]
[TestCase("blah,data:image/jpg;base64,blah")]
public void AddImageprefix_KeepsInputStringWhenNeeded(string originalString)
{
    // Arrange

    // Act
    var result = AddImagePrefix(originalString);

    // Assert
    result.Should().BeEquivalentTo($"data:image/jpg;base64");
}

[dupdob]

yes, this will avoid having duplicate/similar mutants