function testCreationOfSnapShots()
 {
     $this->assertEmpty(self::$initSnap->timePassed());
     $this->assertNotEmpty(self::$initSnap->numClassesDeclaredSincePreviousSnapshot());
     $this->assertNotEmpty(self::$initSnap->numFilesIncludedSincePreviousSnapshot());
     usleep(100);
     $snapShot = new PerformanceSnapshot(self::$initSnap);
     $this->assertNotEmpty($snapShot->timePassed());
     $bytes = str_repeat('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', 10000);
     $snapShot = new PerformanceSnapshot(self::$initSnap);
     $this->assertNotEmpty($snapShot->memoryAllocationDifference());
 }