diff --git a/src/Symfony/Component/Stopwatch/Tests/StopwatchPeriodTest.php b/src/Symfony/Component/Stopwatch/Tests/StopwatchPeriodTest.php
index e01849d474869..81010a79413fd 100644
--- a/src/Symfony/Component/Stopwatch/Tests/StopwatchPeriodTest.php
+++ b/src/Symfony/Component/Stopwatch/Tests/StopwatchPeriodTest.php
@@ -40,7 +40,7 @@ public function testGetEndTime($end, $useMorePrecision, $expected)
     public function testGetDuration($start, $end, $useMorePrecision, $duration)
     {
         $period = new StopwatchPeriod($start, $end, $useMorePrecision);
-        $this->assertSame($duration, $period->getDuration());
+        $this->assertEqualsWithDelta($duration, $period->getDuration(), \PHP_FLOAT_EPSILON);
     }
 
     public function provideTimeValues()
diff --git a/src/Symfony/Component/Stopwatch/composer.json b/src/Symfony/Component/Stopwatch/composer.json
index 1babf15aed09f..a11dc7960f185 100644
--- a/src/Symfony/Component/Stopwatch/composer.json
+++ b/src/Symfony/Component/Stopwatch/composer.json
@@ -19,6 +19,9 @@
         "php": ">=7.1.3",
         "symfony/service-contracts": "^1.0|^2"
     },
+    "require-dev": {
+        "symfony/polyfill-php72": "~1.5"
+    },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Stopwatch\\": "" },
         "exclude-from-classmap": [