public function testMutators() { $base = ['b', 'c', 'd']; $arr = new ArrayObject($base); $arr->push('e', 'f'); $this->assertEquals(['b', 'c', 'd', 'e', 'f'], $arr->toArray()); $this->assertEquals('f', $arr->pop()); $this->assertEquals('e', $arr->pop()); $arr->prepend('a'); $this->assertEquals(['a', 'b', 'c', 'd'], $arr->toArray()); $this->assertEquals('a', $arr->shift()); $this->assertEquals($base, $arr->toArray()); }