Slowness report format supports copy and paste to PHPUnit --filter

Author: johnkary

UPGRADE.md

@@ -1,3 +1,29 @@
+UPGRADE FROM 3.x to 4.0
+=======================
+
+### Slowness report changes formatting of slow class names
+
+Prior to 4.0 the slowness report displayed the qualified class name in a
+human-readable format as normally seen in code:
+
+    1. 800ms to run JohnKary\PHPUnit\Listener\Tests\SomeSlowTest:testWithDataProvider with data set "Rock"
+
+After 4.0 the slowness report displays class names in a format ready to be
+used with PHPUnit's [--filter option](https://phpunit.readthedocs.io/en/9.5/textui.html?highlight=filter)
+by adding slashes to the namespace delimiter and adding a colon between the
+class and method name:
+
+    1. 800ms to run JohnKary\\PHPUnit\\Listener\\Tests\\SomeSlowTest::testWithDataProvider with data set "Rock"
+
+An individual slow test case can now be re-run by copying and pasting the output
+into a new command:
+
+    vendor/bin/phpunit --filter 'JohnKary\\PHPUnit\\Listener\\Tests\\SomeSlowTest::testWithDataProvider with data set "Rock"'
+
+Note that PHPUnit uses single quotes for the `--filter` option value. See the
+[--filter option documentation](https://phpunit.readthedocs.io/en/9.5/textui.html?highlight=filter)
+for all supported matching patterns.
+
 UPGRADE FROM 2.x to 3.0
 =======================
 

src/SpeedTrapListener.php

@@ -151,11 +151,14 @@ protected function toMilliseconds(float $time): int
     }
 
     /**
-     * Label describing a test.
+     * Label describing a slow test case. Formatted to support copy/paste with
+     * PHPUnit's --filter CLI option:
+     *
+     *     vendor/bin/phpunit --filter 'JohnKary\\PHPUnit\\Listener\\Tests\\SomeSlowTest::testWithDataProvider with data set "Rock"'
      */
     protected function makeLabel(TestCase $test): string
     {
-        return sprintf('%s::%s', get_class($test), $test->getName());
+        return sprintf('%s::%s', addslashes(get_class($test)), $test->getName());
     }
 
     /**