Neos\Flow\Tests\Unit\Http\AbstractMessageTest::byDefaultHeadersOfTheSameNameAreReplaced PHP Method

    public function byDefaultHeadersOfTheSameNameAreReplaced()
    {
        $message = $this->getAbstractMessageMock();
        $message->setHeader('MyHeader', 'MyValue');
        $message->setHeader('MyHeader', 'OtherValue');
        $expectedHeaders = ['MyHeader' => ['OtherValue']];
        $this->assertEquals($expectedHeaders, $message->getHeaders()->getAll());
    }