Clone arguments for SpyCall

Prevents bugs where arguments can be mutated after the call.

src/Spies/Helpers.php

@@ -33,4 +33,16 @@ private static function do_vals_match( $a, $b ) {
 		}
 		return false;
 	}
+
+	public static function array_clone( $array ) {
+		return array_map( function( $element ) {
+			return ( ( is_array( $element ) )
+				? call_user_func( __FUNCTION__, $element )
+				: ( ( is_object( $element ) )
+				? clone $element
+				: $element
+			)
+		);
+		}, $array );
+	}
 }

src/Spies/Spy.php

@@ -367,7 +367,8 @@ private function set_arguments( $args ) {
 	 *
 	 * You should not need to call this directly.
 	 */
-	private function record_function_call( $args ) {
+	private function record_function_call( $orig_args ) {
+		$args = Helpers::array_clone( $orig_args );
 		$this->call_record[] = new SpyCall( $args );
 	}
 

tests/SpyTest.php

@@ -139,6 +139,17 @@ public function test_spy_was_called_when_returns_false_if_the_spy_was_called_whe
 		} ) );
 	}
 
+	public function test_spy_was_called_when_uses_a_copy_of_the_arguments_as_they_were_when_the_call_occurred() {
+		$spy = \Spies\make_spy();
+		$obj = new \StdClass();
+		$obj->foo = 'original';
+		$spy( $obj );
+		$obj->foo = 'modified';
+		$this->assertTrue( $spy->was_called_when( function( $args ) {
+			return $args[0]->foo === 'original';
+		} ) );
+	}
+
 	public function test_spy_was_called_before_returns_true_if_called_before_target_spy() {
 		$spy_1 = \Spies\make_spy();
 		$spy_2 = \Spies\make_spy();