minor #15746 Tests fix clockmock (ewgRa)

This PR was squashed before being merged into the 2.3 branch (closes #15746).

Discussion
----------

Tests fix clockmock

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

On my local computer tests for HttpCacheTest not passed, because ClockMock make side effects on another tests (it takes time from _SERVER['REQUEST_TIME'] and for my computer difference with real one time and this time was more than expected by HttpCacheTest, one part of code take time from mock, anothers - from native time function). This PR remove this side effects.

Commits
-------

6b21752 Tests fix clockmock

src/Symfony/Component/HttpFoundation/Tests/ClockMock.php

@@ -18,7 +18,22 @@ function time($asFloat = false)
 
 namespace Symfony\Component\HttpFoundation\Tests;
 
+function with_clock_mock($enable = null)
+{
+    static $enabled;
+
+    if (null === $enable) {
+        return $enabled;
+    }
+
+    $enabled = $enable;
+}
+
 function time()
 {
+    if (!with_clock_mock()) {
+        return \time();
+    }
+
     return $_SERVER['REQUEST_TIME'];
 }

src/Symfony/Component/HttpFoundation/Tests/CookieTest.php

@@ -23,6 +23,18 @@ require_once __DIR__.'/ClockMock.php';
  */
 class CookieTest extends \PHPUnit_Framework_TestCase
 {
+    public function setUp()
+    {
+        with_clock_mock(true);
+        parent::setUp();
+    }
+
+    public function tearDown()
+    {
+        with_clock_mock(false);
+        parent::tearDown();
+    }
+
     public function invalidNames()
     {
         return array(

src/Symfony/Component/HttpFoundation/Tests/ResponseHeaderBagTest.php

@@ -18,6 +18,18 @@ require_once __DIR__.'/ClockMock.php';
 
 class ResponseHeaderBagTest extends \PHPUnit_Framework_TestCase
 {
+    public function setUp()
+    {
+        with_clock_mock(true);
+        parent::setUp();
+    }
+
+    public function tearDown()
+    {
+        with_clock_mock(false);
+        parent::tearDown();
+    }
+
     /**
      * @covers Symfony\Component\HttpFoundation\ResponseHeaderBag::allPreserveCase
      * @dataProvider provideAllPreserveCase

src/Symfony/Component/Stopwatch/Tests/ClockMock.php

@@ -18,10 +18,27 @@ function microtime($asFloat = false)
 
 namespace Symfony\Component\Stopwatch\Tests;
 
+function with_clock_mock($enable = null)
+{
+    static $enabled;
+
+    if (null === $enable) {
+        return $enabled;
+    }
+
+    $enabled = $enable;
+}
+
 function usleep($us)
 {
     static $now;
 
+    if (!with_clock_mock()) {
+        \usleep($us);
+
+        return;
+    }
+
     if (null === $now) {
         $now = \microtime(true);
     }
@@ -31,6 +48,10 @@ function usleep($us)
 
 function microtime($asFloat = false)
 {
+    if (!with_clock_mock()) {
+        return \microtime($asFloat);
+    }
+
     if (!$asFloat) {
         return \microtime(false);
     }

src/Symfony/Component/Stopwatch/Tests/StopwatchEventTest.php

@@ -24,6 +24,18 @@ class StopwatchEventTest extends \PHPUnit_Framework_TestCase
 {
     const DELTA = 37;
 
+    public function setUp()
+    {
+        with_clock_mock(true);
+        parent::setUp();
+    }
+
+    public function tearDown()
+    {
+        with_clock_mock(false);
+        parent::tearDown();
+    }
+
     public function testGetOrigin()
     {
         $event = new StopwatchEvent(12);

src/Symfony/Component/Stopwatch/Tests/StopwatchTest.php

@@ -24,6 +24,18 @@ class StopwatchTest extends \PHPUnit_Framework_TestCase
 {
     const DELTA = 20;
 
+    public function setUp()
+    {
+        with_clock_mock(true);
+        parent::setUp();
+    }
+
+    public function tearDown()
+    {
+        with_clock_mock(false);
+        parent::tearDown();
+    }
+
     public function testStart()
     {
         $stopwatch = new Stopwatch();