diff --git a/src/Framework/Constraint/ArraySubset.php b/src/Framework/Constraint/ArraySubset.php
index 52493727b13..3135e516afe 100644
--- a/src/Framework/Constraint/ArraySubset.php
+++ b/src/Framework/Constraint/ArraySubset.php
@@ -83,8 +83,8 @@ public function evaluate($other, $description = '', $returnResult = false)
             $f = new ComparisonFailure(
                 $patched,
                 $other,
-                \print_r($patched, true),
-                \print_r($other, true)
+                \var_export($patched, true),
+                \var_export($other, true)
             );
 
             $this->fail($other, $description, $f);
diff --git a/tests/unit/Framework/Constraint/ArraySubsetTest.php b/tests/unit/Framework/Constraint/ArraySubsetTest.php
index f48dd3ec19f..2d35b36743e 100644
--- a/tests/unit/Framework/Constraint/ArraySubsetTest.php
+++ b/tests/unit/Framework/Constraint/ArraySubsetTest.php
@@ -77,8 +77,8 @@ public function testEvaluateFailMessage()
         } catch (ExpectationFailedException $expectedException) {
             $comparisonFailure = $expectedException->getComparisonFailure();
             $this->assertNotNull($comparisonFailure);
-            $this->assertContains('[foo] => bar', $comparisonFailure->getExpectedAsString());
-            $this->assertContains('[baz] => bar', $comparisonFailure->getActualAsString());
+            $this->assertContains("'foo' => 'bar'", $comparisonFailure->getExpectedAsString());
+            $this->assertContains("'baz' => 'bar'", $comparisonFailure->getActualAsString());
         }
     }
 }