Fix unit tests by aliasing PHPUnit_Framework_TestCase with namespaced name

[TysonAndre]

This change is intended to work in php 5.2+, the lowest version .travis.yml
indicates this supports.

If PHPUnit_Framework_TestCase does not exist, check if
PHPUnit\Framework\TestCase does exist, and if so, alias it.

• Different versions of phpunit may be required for different php
  versions, so don't try standardizing for now.

Fixes #279

[TysonAndre]

https://travis-ci.org/rmccue/Requests/jobs/239492433 failed for the below reason

https://phpunit.de/manual/current/en/writing-tests-for-phpunit.html

You should be as specific as possible when testing exceptions. Testing for classes that are too generic might lead to undesirable side-effects. Accordingly, testing for the Exception class with @ExpectedException or setExpectedException() is no longer permitted.

Will fix this later, or rebase if another PR fixes that.

[rmccue]

@TysonAndre The way I read that message is that when you call setExpectedException, you can't say you're expecting instances of Exception, but you can use more specific ones.

Based on sebastianbergmann/phpunit#2074 it seems like we just need to use $this->expectException instead.

[codecov-io]

Codecov Report

Merging #280 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #280   +/-   ##
=======================================
  Coverage   92.11%   92.11%           
=======================================
  Files          21       21           
  Lines        1762     1762           
=======================================
  Hits         1623     1623           
  Misses        139      139

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[rmccue]

🙌 Finally passing!

Needs a review from a committer though :)

[rmccue]

(These changes aren't relevant, I just happened to notice the misspelling as I was fixing it.)

[rmccue]

@TysonAndre Thanks for helping out with this issue (and on the others) by the way; you now have commit access. :)

[ptasker]

I've tried to get the tests running a few times and it keeps bailing on the fsockopen Transport tests. Any tips on getting those running?

PHPUnit 6.2.3
PHP 7.1.3

There were 3 failures:

1) RequestsTest_Transport_fsockopen::testResponseByteLimit
Failed asserting that 99 matches expected 104.

/Users/petertasker/working/Requests/tests/Transport/Base.php:48

2) RequestsTest_Transport_fsockopen::testStreamToFile
Failed asserting that null matches expected 'http://requests-php-tests.herokuapp.com/get'.

/Users/petertasker/working/Requests/tests/Transport/Base.php:489

3) RequestsTest_Transport_fsockopen::testMultipleToFile
Failed asserting that null matches expected 'http://requests-php-tests.herokuapp.com/get'.

/Users/petertasker/working/Requests/tests/Transport/Base.php:749

[ozh]

Screw it. I'm done.

[rmccue]

Thanks for this @TysonAndre, we ended up fixing it finally in #303.