PHPLIB-530: Sort MapReduce results before comparing

With MR being moved to aggregation, result order can sometimes be different than expected. This adds a sort function before assertions to avoid test failures due to sorting.

tests/Operation/MapReduceFunctionalTest.php

@@ -9,7 +9,9 @@ use MongoDB\Operation\DropCollection;
 use MongoDB\Operation\Find;
 use MongoDB\Operation\MapReduce;
 use MongoDB\Tests\CommandObserver;
+use function is_object;
 use function iterator_to_array;
+use function usort;
 use function version_compare;
 
 class MapReduceFunctionalTest extends FunctionalTestCase
@@ -237,7 +239,7 @@ class MapReduceFunctionalTest extends FunctionalTestCase
         $operation = new MapReduce($this->getDatabaseName(), $this->getCollectionName(), $map, $reduce, $out, ['typeMap' => $typeMap]);
         $results = iterator_to_array($operation->execute($this->getPrimaryServer()));
 
-        $this->assertEquals($expectedDocuments, $results);
+        $this->assertEquals($this->sortResults($expectedDocuments), $this->sortResults($results));
     }
 
     public function provideTypeMapOptionsAndExpectedDocuments()
@@ -284,12 +286,12 @@ class MapReduceFunctionalTest extends FunctionalTestCase
         $operation = new MapReduce($this->getDatabaseName(), $this->getCollectionName(), $map, $reduce, $out, ['typeMap' => $typeMap]);
         $results = iterator_to_array($operation->execute($this->getPrimaryServer()));
 
-        $this->assertEquals($expectedDocuments, $results);
+        $this->assertEquals($this->sortResults($expectedDocuments), $this->sortResults($results));
 
         $operation = new Find($this->getDatabaseName(), $out, [], ['typeMap' => $typeMap]);
         $cursor = $operation->execute($this->getPrimaryServer());
 
-        $this->assertEquals($expectedDocuments, iterator_to_array($cursor));
+        $this->assertEquals($this->sortResults($expectedDocuments), $this->sortResults(iterator_to_array($cursor)));
 
         $operation = new DropCollection($this->getDatabaseName(), $out);
         $operation->execute($this->getPrimaryServer());
@@ -313,4 +315,19 @@ class MapReduceFunctionalTest extends FunctionalTestCase
 
         $this->assertEquals($n * 2, $result->getInsertedCount());
     }
+
+    private function sortResults(array $results) : array
+    {
+        $sortFunction = static function ($resultA, $resultB) : int {
+            $idA = is_object($resultA) ? $resultA->_id : $resultA['_id'];
+            $idB = is_object($resultB) ? $resultB->_id : $resultB['_id'];
+
+            return $idA <=> $idB;
+        };
+
+        $sortedResults = $results;
+        usort($sortedResults, $sortFunction);
+
+        return $sortedResults;
+    }
 }