[tests] mutation not covered: callbacks in TestSuite

[ngarbezza]

Problem

These two mutations of the code do not trigger a failure in the test suite.

Original:

run(context) {
    this._callbacks.onStart(this);
    this._evaluateSuiteDefinition();
    this._runTests(context);
    this._callbacks.onFinish(this);
  }

mutation 1:

run(context) {
    // this._callbacks.onStart(this);
    this._evaluateSuiteDefinition();
    this._runTests(context);
    this._callbacks.onFinish(this);
  }

mutation 2:

run(context) {
    this._callbacks.onStart(this);
    this._evaluateSuiteDefinition();
    this._runTests(context);
    // this._callbacks.onFinish(this);
  }

Proposed solution
Write tests to make sure those callbacks are executed and the mutation actually makes those tests fail