Add Mock Client strategy.

[samrap]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Related tickets	mentioned in #89
Documentation	php-http/documentation#173
License	MIT

What's in this PR?

Please see #89 for a full description of this PR.

Essentially, we need a way to test DI within our tests which in many cases cannot be fully implemented without having some way to discover the Mock Client. This new class allows us to add the MockClientStrategy to the HttpClientDiscovery's strategies as shown in @Nyholm 's example in the above mentioned PR.

Example Usage

use ThirdPartyService

class ThirdPartyServiceTest extends PHPUnit_Framework_TestCase
{
    public function setUpBeforeClass()
    {
        HttpClientDiscovery::prependStrategy(MockClientStrategy::class);
    }

    public function setUp()
    {
        $this->service = new ThirdPartyService;
    }
}

Checklist

• Updated CHANGELOG.md to describe BC breaks / deprecations | new feature | bugfix
• Documentation pull request created (if not simply a bugfix)

[Nyholm]

Good. Make sure to create a PR to the docs explaining this strategy, why, how and that it is not loaded by default.

[Nyholm]

No need for final annotation

[samrap]

👍

[Nyholm]

Is this strategy really internal? The others are, but it is meant that this class should be used by others, right?

[sagikazarmark]

You could use the ::class constant here

[samrap]

Good call, changing that now.

[sagikazarmark]

@samrap thanks for your contribution.

What do you think about #89 (comment) ?

[samrap]

@sagikazarmark I prefer sticking with a manual setup in the test class i.e:

public function setUp()
{
    HttpClientDiscovery::prependStrategy(MockClientStrategy::class);
}

Adding a trait or method(s) to the Mock Client to add itself to the Discovery means the strategy now depends on the Discovery which seems like an unnecessary dependency to me. Unless I'm understanding this wrong.

As far as @barryvdh suggestion for Discovery::enableMockClient(), I like that idea. What do you think?

[sagikazarmark]

Adding a trait or method(s) to the Mock Client to add itself to the

I rather meant a trait or base class for PHPUnit test cases, but I realized that MockClient is not limited to be used in PHPUnit, so that's probably not really good idea.

[Nyholm]

I do not like Discovery::enableMockClient. No discovery strategy should be treated in special manners.

[samrap]

@Nyholm good point. So I think we should keep this as is, and I will work on getting those docs completed.

[samrap]

Just FYI still active on this, been busy at work but will get these docs by end of week.

[samrap]

See php-http/documentation#173 👍

[Nyholm]

Thank you for this PR.

[samrap]

Thank you guys!