diff --git a/src/Symfony/Bridge/PhpUnit/ClockMock.php b/src/Symfony/Bridge/PhpUnit/ClockMock.php
index 5cd3531d6b..962649bcd6 100644
--- a/src/Symfony/Bridge/PhpUnit/ClockMock.php
+++ b/src/Symfony/Bridge/PhpUnit/ClockMock.php
@@ -66,7 +66,7 @@ class ClockMock
             return self::$now;
         }
 
-        return sprintf('%0.6f %d', self::$now - (int) self::$now, (int) self::$now);
+        return sprintf('%0.6f00 %d', self::$now - (int) self::$now, (int) self::$now);
     }
 
     public static function register($class)
diff --git a/src/Symfony/Bridge/PhpUnit/Tests/ClockMockTest.php b/src/Symfony/Bridge/PhpUnit/Tests/ClockMockTest.php
new file mode 100644
index 0000000000..82cfb6f566
--- /dev/null
+++ b/src/Symfony/Bridge/PhpUnit/Tests/ClockMockTest.php
@@ -0,0 +1,60 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\PhpUnit\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Bridge\PhpUnit\ClockMock;
+
+/**
+ * @author Dominic Tubach <dominic.tubach@to.com>
+ *
+ * @covers \Symfony\Bridge\PhpUnit\ClockMock
+ */
+class ClockMockTest extends TestCase
+{
+    public static function setUpBeforeClass()
+    {
+        ClockMock::register(__CLASS__);
+    }
+
+    protected function setUp()
+    {
+        ClockMock::withClockMock(1234567890.125);
+    }
+
+    public function testTime()
+    {
+        $this->assertSame(1234567890, time());
+    }
+
+    public function testSleep()
+    {
+        sleep(2);
+        $this->assertSame(1234567892, time());
+    }
+
+    public function testMicrotime()
+    {
+        $this->assertSame('0.12500000 1234567890', microtime());
+    }
+
+    public function testMicrotimeAsFloat()
+    {
+        $this->assertSame(1234567890.125, microtime(true));
+    }
+
+    public function testUsleep()
+    {
+        usleep(2);
+        $this->assertSame(1234567890.125002, microtime(true));
+    }
+}