Unit tests for Distinct operation and allow array/object $filter

src/Collection.php

@@ -228,11 +228,11 @@ class Collection
      *
      * @see Distinct::__construct() for supported options
      * @param string $fieldName Field for which to return distinct values
-     * @param array  $filter    Query by which to filter documents
+     * @param array|object $filter  Query by which to filter documents
      * @param array        $options Command options
      * @return mixed[]
      */
-    public function distinct($fieldName, array $filter = array(), array $options = array())
+    public function distinct($fieldName, $filter = array(), array $options = array())
     {
         $operation = new Distinct($this->dbname, $this->collname, $fieldName, $filter, $options);
         $server = $this->manager->selectServer(new ReadPreference(ReadPreference::RP_PRIMARY));

src/Operation/Distinct.php

@@ -39,8 +39,12 @@ class Distinct implements Executable
      * @param array  $options        Command options
      * @throws InvalidArgumentException
      */
-    public function __construct($databaseName, $collectionName, $fieldName, array $filter = array(), array $options = array())
+    public function __construct($databaseName, $collectionName, $fieldName, $filter = array(), array $options = array())
     {
+        if ( ! is_array($filter) && ! is_object($filter)) {
+            throw new InvalidArgumentTypeException('$filter', $filter, 'array or object');
+        }
+
         if (isset($options['maxTimeMS']) && ! is_integer($options['maxTimeMS'])) {
             throw new InvalidArgumentTypeException('"maxTimeMS" option', $options['maxTimeMS'], 'integer');
         }

tests/Operation/DistinctTest.php

+<?php
+
+namespace MongoDB\Tests\Operation;
+
+use MongoDB\Operation\Distinct;
+
+class DistinctTest extends TestCase
+{
+    /**
+     * @expectedException MongoDB\Exception\InvalidArgumentTypeException
+     * @dataProvider provideInvalidDocumentValues
+     */
+    public function testConstructorFilterArgumentTypeCheck($filter)
+    {
+        new Distinct($this->getDatabaseName(), $this->getCollectionName(), 'x', $filter);
+    }
+
+    /**
+     * @expectedException MongoDB\Exception\InvalidArgumentTypeException
+     * @dataProvider provideInvalidConstructorOptions
+     */
+    public function testConstructorOptionTypeChecks(array $options)
+    {
+        new Distinct($this->getDatabaseName(), $this->getCollectionName(), 'x', array(), $options);
+    }
+
+    public function provideInvalidConstructorOptions()
+    {
+        $options = array();
+
+        foreach ($this->getInvalidIntegerValues() as $value) {
+            $options[][] = array('maxTimeMS' => $value);
+        }
+
+        return $options;
+    }
+}