public function testContains() { $collection = new Collection(['a' => 'x', 'b' => 'Y']); $this->assertTrue($collection->contains('x')); $this->assertTrue($collection->contains('X')); $this->assertFalse($collection->contains('X', true)); $this->assertTrue($collection->contains('y')); $this->assertFalse($collection->contains('y', true)); }