Stryker: SwitchCase mutation mishandles empty fallthrough cases

[CheshireSwift]

Summary

When handling an empty fallthrough case, e.g.:

switch (value) {
  case 'A':
  case 'B':
    ...
}

SwitchCase will raise an unchanged (thus unkillable) mutant which simply removes + readds the case 'A' (maybe changing the formatting slightly, but not the semantics).

Stryker config

module.exports = function(config) {
  config.set({
    mutator: "javascript",
    packageManager: "npm",
    reporters: ["clear-text", "progress"],
    testRunner: "jest",
    transpilers: [],
    coverageAnalysis: "off",
    mutate: ["src/**/*.js"]
  });
};

Stryker environment

[email protected]
[email protected]
[email protected]
[email protected]

[email protected]

Your Environment

| software | version(s)
| ---------------- | -------
| node | multiple
| npm | multiple
| Operating System | multiple

Add stryker.log

stryker.log

Executable repro repo here.

[nicojs]

Thanks for reporting. This is most definitely a bug. It is recently introduced as this is a new mutator. @tommilligan would you mind taking a look? Maybe if you have some time, fixing this issue? Thanks for any feedback you might have.

[tommilligan]

No problem, will put in a fix this evening. Thanks for letting me know

[kmdrGroch]

@nicojs I think it is ready to close

[Archcry]

Closing this issue, when you encounter further problems feel free to reopen.