Differ - fix diffing array's.

Author: SpacePossum

src/Differ.php

@@ -61,8 +61,8 @@ public function __construct($outputBuilder = null)
      */
     public function diff($from, $to, LongestCommonSubsequenceCalculator $lcs = null): string
     {
-        $from = $this->validateDiffInput($from);
-        $to   = $this->validateDiffInput($to);
+        $from = $this->normalizeDiffInput($from);
+        $to   = $this->normalizeDiffInput($to);
         $diff = $this->diffToArray($from, $to, $lcs);
 
         return $this->outputBuilder->getDiff($diff);
@@ -73,9 +73,9 @@ public function diff($from, $to, LongestCommonSubsequenceCalculator $lcs = null)
      *
      * @param mixed $input
      *
-     * @return string
+     * @return string|array
      */
-    private function validateDiffInput($input): string
+    private function normalizeDiffInput($input)
     {
         if (!\is_array($input) && !\is_string($input)) {
             return (string) $input;

tests/DifferTest.php

@@ -90,6 +90,19 @@ public function testTypesOtherThanArrayAndStringCanBePassed()
         );
     }
 
+    public function testArrayDiffs()
+    {
+        $this->assertSame(
+            '--- Original
++++ New
+@@ @@
+-one
++two
+',
+            $this->differ->diff(array('one'), array('two'))
+        );
+    }
+
     public function arrayProvider(): array
     {
         return [