GuzzleHttp\Tests\ClientTest::testMergesDefaultOptionsAndDoesNotOverwriteUa PHP Method

    public function testMergesDefaultOptionsAndDoesNotOverwriteUa()
    {
        $c = new Client(['headers' => ['User-agent' => 'foo']]);
        $this->assertEquals(['User-agent' => 'foo'], $c->getConfig('headers'));
        $this->assertInternalType('array', $c->getConfig('allow_redirects'));
        $this->assertTrue($c->getConfig('http_errors'));
        $this->assertTrue($c->getConfig('decode_content'));
        $this->assertTrue($c->getConfig('verify'));
    }