Hash provided in File\Hash validator must be a string

We were checking it when we providing one hash, but there
was no check for array:
```
$options = [
   'hash1',
   'hash2',
   // ...
   'algorithm' => '...',
];
```

Author: michalbundyra

src/File/Hash.php

@@ -114,6 +114,12 @@ public function addHash($options)
         }
 
         foreach ($options as $value) {
+            if (! is_string($value)) {
+                throw new Exception\InvalidArgumentException(sprintf(
+                    'Hash must be a string, %s received',
+                    is_object($value) ? get_class($value) : gettype($value)
+                ));
+            }
             $this->options['hash'][$value] = $algorithm;
         }
 

test/File/HashTest.php

@@ -239,4 +239,18 @@ public function testConstructorCanAcceptAllOptionsAsDiscreteArguments()
         $options = $r->getValue($validator);
         $this->assertSame($algorithm, $options['algorithm']);
     }
+
+    /**
+     * @dataProvider invalidHashTypes
+     *
+     * @param mixed $hash
+     */
+    public function testInvalidHashProvidedInArrayFormat($hash)
+    {
+        $validator = new File\Hash('12345');
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Hash must be a string');
+        $validator->addHash([$hash]);
+    }
 }