Returns the description of the failure
The beginning of failure messages is "Failed asserting that" in most cases. This method should return the second part of that sentence.
mixed $other Evaluated value or object.:
string
Overrides PHPUnit_Framework_Constraint::failureDescription
protected function failureDescription($other) {
return sprintf("exception message '%s' contains '%s'", $other
->getMessage(), $this->expectedMessage);
}