@Override
  public String getMessage() {
    return "Condition not satisfied:\n\n" + condition.getRendering();
  }
Thrown when a condition of the form 'expr1 == expr2' fails.
Inherits from JUnit's ComparisonFailure (rather than
ConditionNotSatisfiedError) to enable IDE support for
diff'ing actual and expected values.

@author Peter Niederwieser
spock-core/src/main/java/org/spockframework/runtime/SpockComparisonFailure.java