+ );
+ usort($pairs, array(__CLASS__, 'compareDupes'));
+ usort($expectedPairs, array(__CLASS__, 'compareDupes'));
+ $this->assertEquals($expectedPairs, $pairs);
+ }
+
+ /**
+ * Function to sort $duplicate records in a stable way.
+ *
+ * @param array $a
+ * @param array $b
+ * @return int
+ */
+ public static function compareDupes($a, $b) {
+ foreach (array('srcName', 'dstName', 'srcID', 'dstID') as $field) {
+ if ($a[$field] != $b[$field]) {
+ return ($a[$field] < $b[$field]) ? 1 : -1;
+ }
+ }
+ return 0;