diff --git a/tests/_files/bar.txt b/tests/_files/bar.txt
index 5acdde49d10..351f9261cd1 100644
--- a/tests/_files/bar.txt
+++ b/tests/_files/bar.txt
@@ -1 +1 @@
-Test for compare file
+Voulez-vous un café?
diff --git a/tests/_files/foo.txt b/tests/_files/foo.txt
index 0fdeb064721..f4fe32c14f6 100644
--- a/tests/_files/foo.txt
+++ b/tests/_files/foo.txt
@@ -1 +1 @@
-Test file for compare
+Voulez-vous un café?
diff --git a/tests/unit/Framework/AssertTest.php b/tests/unit/Framework/AssertTest.php
index 81fd17f31c9..127d555f9c5 100644
--- a/tests/unit/Framework/AssertTest.php
+++ b/tests/unit/Framework/AssertTest.php
@@ -1572,6 +1572,9 @@ public function testAssertStringNotMatchesFormatFile(): void
 
     public function testAssertFileEqualsCanonicalizing(): void
     {
+        //Check that files is not equal by simple compare
+        $this->assertFileNotEquals(TEST_FILES_PATH . 'foo.txt', TEST_FILES_PATH . 'bar.txt');
+
         $this->assertFileEqualsCanonicalizing(TEST_FILES_PATH . 'foo.txt', TEST_FILES_PATH . 'foo.txt');
 
         $this->assertFileEqualsCanonicalizing(TEST_FILES_PATH . 'foo.txt', TEST_FILES_PATH . 'bar.txt');