diff --git a/core/lib/Drupal/Core/Test/JUnitListener.php b/core/lib/Drupal/Core/Test/JUnitListener.php
index 2f23fcdcf9..0f586337c7 100644
--- a/core/lib/Drupal/Core/Test/JUnitListener.php
+++ b/core/lib/Drupal/Core/Test/JUnitListener.php
@@ -12,7 +12,6 @@
 use PHPUnit\Framework\TestSuite;
 use PHPUnit\Framework\Warning;
 use PHPUnit\Util\Filter;
-use PHPUnit\Util\Printer;
 use PHPUnit\Util\Xml;
 
 /**
@@ -43,44 +42,9 @@ class JUnitListener implements TestListener {
   protected $testSuites = [];
 
   /**
-   * @var int[]
+   * @var array
    */
-  protected $testSuiteTests = [0];
-
-  /**
-   * @var int[]
-   */
-  protected $testSuiteAssertions = [0];
-
-  /**
-   * @var int[]
-   */
-  protected $testSuiteErrors = [0];
-
-  /**
-   * @var int[]
-   */
-  protected $testSuiteFailures = [0];
-
-  /**
-   * @var int[]
-   */
-  protected $testSuiteRisky = [0];
-
-  /**
-   * @var int[]
-   */
-  protected $testSuiteSkipped = [0];
-
-  /**
-   * @var int[]
-   */
-  protected $testSuiteIncomplete = [0];
-
-  /**
-   * @var int[]
-   */
-  protected $testSuiteTimes = [0];
+  protected $testSuiteRuns = [];
 
   /**
    * @var int
@@ -122,7 +86,7 @@ public function __destruct() {
    */
   public function addError(Test $test, \Exception $e, $time) {
     $this->doAddFault($test, $e, $time, 'error');
-    $this->testSuiteErrors[$this->testSuiteLevel]++;
+    $this->testSuiteRuns[$this->testSuiteLevel]['errors']++;
   }
 
   /**
@@ -134,7 +98,7 @@ public function addError(Test $test, \Exception $e, $time) {
    */
   public function addWarning(Test $test, Warning $e, $time) {
     $this->doAddFault($test, $e, $time, 'warning');
-    $this->testSuiteFailures[$this->testSuiteLevel]++;
+    $this->testSuiteRuns[$this->testSuiteLevel]['failures']++;
   }
 
   /**
@@ -146,7 +110,7 @@ public function addWarning(Test $test, Warning $e, $time) {
    */
   public function addFailure(Test $test, AssertionFailedError $e, $time) {
     $this->doAddFault($test, $e, $time, 'failure');
-    $this->testSuiteFailures[$this->testSuiteLevel]++;
+    $this->testSuiteRuns[$this->testSuiteLevel]['failures']++;
   }
 
   /**
@@ -194,25 +158,29 @@ public function startTestSuite(TestSuite $suite) {
       try {
         $class = new \ReflectionClass($suite->getName());
         $testSuite->setAttribute('file', $class->getFileName());
-      } catch (\ReflectionException $e) {
+      }
+      catch (\ReflectionException $e) {
         // Do nothing.
       }
     }
     if ($this->testSuiteLevel > 0) {
       $this->testSuites[$this->testSuiteLevel]->appendChild($testSuite);
-    } else {
+    }
+    else {
       $this->root->appendChild($testSuite);
     }
     $this->testSuiteLevel++;
     $this->testSuites[$this->testSuiteLevel] = $testSuite;
-    $this->testSuiteTests[$this->testSuiteLevel] = 0;
-    $this->testSuiteAssertions[$this->testSuiteLevel] = 0;
-    $this->testSuiteErrors[$this->testSuiteLevel] = 0;
-    $this->testSuiteRisky[$this->testSuiteLevel] = 0;
-    $this->testSuiteFailures[$this->testSuiteLevel] = 0;
-    $this->testSuiteSkipped[$this->testSuiteLevel] = 0;
-    $this->testSuiteIncomplete[$this->testSuiteLevel] = 0;
-    $this->testSuiteTimes[$this->testSuiteLevel] = 0;
+    $this->testSuiteRuns[$this->testSuiteLevel] = [
+      'tests' => 0,
+      'assertions' => 0,
+      'errors' => 0,
+      'failures' => 0,
+      'risky' => 0,
+      'skipped' => 0,
+      'incomplete' => 0,
+      'time' => 0,
+    ];
   }
 
   /**
@@ -221,23 +189,28 @@ public function startTestSuite(TestSuite $suite) {
    * @param \PHPUnit\Framework\TestSuite $suite
    */
   public function endTestSuite(TestSuite $suite) {
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('tests', $this->testSuiteTests[$this->testSuiteLevel]);
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('assertions', $this->testSuiteAssertions[$this->testSuiteLevel]);
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('errors', $this->testSuiteErrors[$this->testSuiteLevel]);
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('failures', $this->testSuiteFailures[$this->testSuiteLevel]);
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('risky', $this->testSuiteRisky[$this->testSuiteLevel]);
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('skipped', $this->testSuiteSkipped[$this->testSuiteLevel]);
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('incomplete', $this->testSuiteIncomplete[$this->testSuiteLevel]);
-    $this->testSuites[$this->testSuiteLevel]->setAttribute('time', sprintf('%F', $this->testSuiteTimes[$this->testSuiteLevel]));
+    $properties = [
+      'tests',
+      'assertions',
+      'errors',
+      'failures',
+      'risky',
+      'skipped',
+      'incomplete',
+    ];
+
+    // Add summary to the <testsuite> DOM element.
+    foreach ($properties as $property) {
+      $this->testSuites[$this->testSuiteLevel]->setAttribute($property, $this->testSuiteRuns[$this->testSuiteLevel][$property]);
+    }
+    $this->testSuites[$this->testSuiteLevel]->setAttribute('time', sprintf('%F', $this->testSuiteRuns[$this->testSuiteLevel]['time']));
+
+    // When nesting, sum up results to the parent testsuite.
     if ($this->testSuiteLevel > 1) {
-      $this->testSuiteTests[$this->testSuiteLevel - 1] += $this->testSuiteTests[$this->testSuiteLevel];
-      $this->testSuiteAssertions[$this->testSuiteLevel - 1] += $this->testSuiteAssertions[$this->testSuiteLevel];
-      $this->testSuiteErrors[$this->testSuiteLevel - 1] += $this->testSuiteErrors[$this->testSuiteLevel];
-      $this->testSuiteFailures[$this->testSuiteLevel - 1] += $this->testSuiteFailures[$this->testSuiteLevel];
-      $this->testSuiteRisky[$this->testSuiteLevel - 1] += $this->testSuiteRisky[$this->testSuiteLevel];
-      $this->testSuiteSkipped[$this->testSuiteLevel - 1] += $this->testSuiteSkipped[$this->testSuiteLevel];
-      $this->testSuiteIncomplete[$this->testSuiteLevel - 1] += $this->testSuiteIncomplete[$this->testSuiteLevel];
-      $this->testSuiteTimes[$this->testSuiteLevel - 1] += $this->testSuiteTimes[$this->testSuiteLevel];
+      foreach ($properties as $property) {
+        $this->testSuiteRuns[$this->testSuiteLevel - 1][$property] += $this->testSuiteRuns[$this->testSuiteLevel][$property];
+      }
+      $this->testSuiteRuns[$this->testSuiteLevel - 1]['time'] += $this->testSuiteRuns[$this->testSuiteLevel]['time'];
     }
     $this->testSuiteLevel--;
   }
@@ -252,7 +225,7 @@ public function startTest(Test $test) {
     $testCase->setAttribute('name', $test->getName());
 
     if ($test instanceof TestCase) {
-      $class      = new \ReflectionClass($test);
+      $class = new \ReflectionClass($test);
       $methodName = $test->getName(!$test->usesDataProvider());
 
       if ($class->hasMethod($methodName)) {
@@ -277,7 +250,7 @@ public function startTest(Test $test) {
   public function endTest(Test $test, $time) {
     if ($test instanceof TestCase) {
       $num_assertions = $test->getNumAssertions();
-      $this->testSuiteAssertions[$this->testSuiteLevel] += $num_assertions;
+      $this->testSuiteRuns[$this->testSuiteLevel]['assertions'] += $num_assertions;
 
       $this->currentTestCase->setAttribute('assertions', $num_assertions);
     }
@@ -288,8 +261,8 @@ public function endTest(Test $test, $time) {
       $this->currentTestCase
     );
 
-    $this->testSuiteTests[$this->testSuiteLevel]++;
-    $this->testSuiteTimes[$this->testSuiteLevel] += $time;
+    $this->testSuiteRuns[$this->testSuiteLevel]['tests']++;
+    $this->testSuiteRuns[$this->testSuiteLevel]['time'] += $time;
 
     if (method_exists($test, 'hasOutput') && $test->hasOutput()) {
       $systemOut = $this->document->createElement('system-out', Xml::prepareString($test->getActualOutput()));
@@ -324,7 +297,8 @@ private function doAddFault(Test $test, \Exception $e, $time, $type) {
 
     if ($test instanceof SelfDescribing) {
       $buffer = $test->toString() . "\n";
-    } else {
+    }
+    else {
       $buffer = '';
     }
 
@@ -334,7 +308,8 @@ private function doAddFault(Test $test, \Exception $e, $time, $type) {
 
     if ($e instanceof ExceptionWrapper) {
       $fault->setAttribute('type', $e->getClassName());
-    } else {
+    }
+    else {
       $fault->setAttribute('type', get_class($e));
     }
 
@@ -362,15 +337,15 @@ private function doAddSkipped(Test $test, $message) {
 
     switch ($message) {
       case 'risky':
-        $this->testSuiteRisky[$this->testSuiteLevel]++;
+        $this->testSuiteRuns[$this->testSuiteLevel]['risky']++;
         break;
 
       case 'skipped':
-        $this->testSuiteSkipped[$this->testSuiteLevel]++;
+        $this->testSuiteRuns[$this->testSuiteLevel]['skipped']++;
         break;
 
       case 'incomplete':
-        $this->testSuiteIncomplete[$this->testSuiteLevel]++;
+        $this->testSuiteRuns[$this->testSuiteLevel]['incomplete']++;
         break;
 
     }