+<?php
+
+/**
+ * Test that a factory class correctly forwards all arguments to the class it constructs. This is
+ * useful because sometimes a class' constructor will have more arguments added, and it's easy to
+ * accidentally have the factory's constructor fall out of sync.
+ */
+trait FactoryArgTestTrait {
+ /**
+ * @return string Name of factory class
+ */
+ abstract protected static function getFactoryClass();
+
+ /**
+ * @return string Name of instance class
+ */
+ abstract protected static function getInstanceClass();
+
+ /**
+ * @return int The number of arguments that the instance constructor receives but the factory
+ * constructor doesn't. Used for a simple argument count check. Override if this isn't zero.
+ */
+ protected static function getExtraClassArgCount() {
+ return 0;
+ }
+
+ /**
+ * Override if your factory method name is different from newInstanceClassName.
+ *
+ * @return string
+ */
+ protected function getFactoryMethodName() {
+ return 'new' . $this->getInstanceClass();
+ }
+
+ /**
+ * Override if $factory->$method( ...$args ) isn't the right way to create an instance, where
+ * $method is returned from getFactoryMethodName(), and $args is constructed by applying
+ * getMockValueForParam() to the factory method's parameters.
+ *
+ * @param object $factory Factory object
+ * @return object Object created by factory
+ */
+ protected function createInstanceFromFactory( $factory ) {
+ $methodName = $this->getFactoryMethodName();
+ $methodObj = new ReflectionMethod( $factory, $methodName );
+ $mocks = [];
+ foreach ( $methodObj->getParameters() as $param ) {
+ $mocks[] = $this->getMockValueForParam( $param );
+ }
+
+ return $factory->$methodName( ...$mocks );
+ }
+
+ public function testConstructorArgNum() {
+ $factoryClass = static::getFactoryClass();
+ $instanceClass = static::getInstanceClass();
+ $factoryConstructor = new ReflectionMethod( $factoryClass, '__construct' );
+ $instanceConstructor = new ReflectionMethod( $instanceClass, '__construct' );
+ $this->assertSame(
+ $instanceConstructor->getNumberOfParameters() - static::getExtraClassArgCount(),
+ $factoryConstructor->getNumberOfParameters(),
+ "$instanceClass and $factoryClass constructors have an inconsistent number of " .
+ ' parameters. Did you add a parameter to one and not the other?' );
+ }
+
+ /**
+ * Override if getMockValueForParam doesn't produce suitable values for one or more of the
+ * parameters to your factory constructor or create method.
+ *
+ * @param ReflectionParameter $param One of the factory constructor's arguments
+ * @return array Empty to not override, or an array of one element which is the value to pass
+ * that will allow the object to be constructed successfully
+ */
+ protected function getOverriddenMockValueForParam( ReflectionParameter $param ) {
+ return [];
+ }
+
+ /**
+ * Override if this doesn't produce suitable values for one or more of the parameters to your
+ * factory constructor or create method.
+ *
+ * @param ReflectionParameter $param One of the factory constructor's arguments
+ * @return mixed A value to pass that will allow the object to be constructed successfully
+ */
+ protected function getMockValueForParam( ReflectionParameter $param ) {
+ $overridden = $this->getOverriddenMockValueForParam( $param );
+ if ( $overridden ) {
+ return $overridden[0];
+ }
+
+ $pos = $param->getPosition();
+
+ $type = (string)$param->getType();
+
+ if ( $type === 'array' ) {
+ return [ "some unlikely string $pos" ];
+ }
+
+ if ( class_exists( $type ) || interface_exists( $type ) ) {
+ return $this->createMock( $type );
+ }
+
+ if ( $type === '' ) {
+ // Optimistically assume a string is okay
+ return "some unlikely string $pos";
+ }
+
+ $this->fail( "Unrecognized parameter type $type" );
+ }
+
+ /**
+ * Assert that the given $instance correctly received $val as the value for parameter $name. By
+ * default, checks that the instance has some member whose value is the same as $val.
+ *
+ * @param object $instance
+ * @param string $name Name of parameter to the factory object's constructor
+ * @param mixed $val
+ */
+ protected function assertInstanceReceivedParam( $instance, $name, $val ) {
+ foreach ( ( new ReflectionObject( $instance ) )->getProperties() as $prop ) {
+ $prop->setAccessible( true );
+ if ( $prop->getValue( $instance ) === $val ) {
+ $this->assertTrue( true );
+ return;
+ }
+ }
+
+ $this->assertFalse( true, "Param $name not received by " . static::getInstanceClass() );
+ }
+
+ public function testAllArgumentsWerePassed() {
+ $factoryClass = static::getFactoryClass();
+
+ $factoryConstructor = new ReflectionMethod( $factoryClass, '__construct' );
+ $mocks = [];
+ foreach ( $factoryConstructor->getParameters() as $param ) {
+ $mocks[$param->getName()] = $this->getMockValueForParam( $param );
+ }
+
+ $instance =
+ $this->createInstanceFromFactory( new $factoryClass( ...array_values( $mocks ) ) );
+
+ foreach ( $mocks as $name => $mock ) {
+ $this->assertInstanceReceivedParam( $instance, $name, $mock );
+ }
+ }
+}