function testSimpleWriteRead()
 {
     $handler = new CoverageDataHandler($this->tempdb());
     $handler->createSchema();
     $coverage = array(10 => -2, 20 => -1, 30 => 0, 40 => 1);
     $handler->write(array('file' => $coverage));
     $actual = $handler->readFile('file');
     $expected = array(10 => -2, 20 => -1, 30 => 0, 40 => 1);
     $this->assertEqual($expected, $actual);
 }