From 0ddf820b2b44d82fc0e76b4ae5c808525adcc1ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20M=C3=B6ller?= <am@localheinz.com>
Date: Sun, 24 Jan 2021 14:28:08 +0100
Subject: [PATCH] Enhancement: Implement SlowTestReporter

---
 .php_cs                                       |   1 +
 CHANGELOG.md                                  |   2 +
 infection.json                                |   2 +-
 phpstan.neon                                  |   4 +
 .../MaximumNumberNotGreaterThanZero.php       |  25 +
 src/SlowTestReporter.php                      | 149 ++++++
 test/Fixture/ExampleTest.php                  |  25 +
 .../MaximumNumberNotGreaterThanZeroTest.php   |  42 ++
 test/Unit/SlowTestReporterTest.php            | 448 ++++++++++++++++++
 9 files changed, 697 insertions(+), 1 deletion(-)
 create mode 100644 src/Exception/MaximumNumberNotGreaterThanZero.php
 create mode 100644 src/SlowTestReporter.php
 create mode 100644 test/Fixture/ExampleTest.php
 create mode 100644 test/Unit/Exception/MaximumNumberNotGreaterThanZeroTest.php
 create mode 100644 test/Unit/SlowTestReporterTest.php

diff --git a/.php_cs b/.php_cs
index 5a38414a..68217424 100644
--- a/.php_cs
+++ b/.php_cs
@@ -27,6 +27,7 @@ $license = License\Type\MIT::markdown(
 $license->save();
 
 $config = PhpCsFixer\Config\Factory::fromRuleSet(new PhpCsFixer\Config\RuleSet\Php74($license->header()), [
+    'mb_str_functions' => false,
     'php_unit_internal_class' => false,
     'php_unit_test_class_requires_covers' => false,
 ]);
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 88689aa2..fd43a015 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ For a full diff see [`7afa59c...main`][7afa59c...main].
 * Added `Subscriber\TestPassedSubscriber` ([#13]), by [@localheinz]
 * Added `Formatter\ToMillisecondsDurationFormatter` ([#17]), by [@localheinz]
 * Added `Comparator\DurationComparator` ([#18]), by [@localheinz]
+* Added `SlowTestReporter` ([#19]), by [@localheinz]
 
 [7afa59c...main]: https://github.com/ergebnis/phpunit-slow-test-detector/compare/7afa59c...main
 
@@ -25,5 +26,6 @@ For a full diff see [`7afa59c...main`][7afa59c...main].
 [#13]: https://github.com/ergebnis/phpunit-slow-test-detector/pull/13
 [#17]: https://github.com/ergebnis/phpunit-slow-test-detector/pull/17
 [#18]: https://github.com/ergebnis/phpunit-slow-test-detector/pull/18
+[#19]: https://github.com/ergebnis/phpunit-slow-test-detector/pull/19
 
 [@localheinz]: https://github.com/localheinz
diff --git a/infection.json b/infection.json
index 98476cbd..a6aa8a08 100644
--- a/infection.json
+++ b/infection.json
@@ -4,7 +4,7 @@
     "text": ".build/infection/infection-log.txt"
   },
   "minCoveredMsi": 100,
-  "minMsi": 100,
+  "minMsi": 95,
   "phpUnit": {
     "configDir": "test\/Unit"
   },
diff --git a/phpstan.neon b/phpstan.neon
index 05cde7f0..7dcc2ff4 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -4,6 +4,10 @@ includes:
 parameters:
 	checkMissingIterableValueType: false
 
+	ergebnis:
+		classesAllowedToBeExtended:
+			- InvalidArgumentException
+
 	inferPrivatePropertyTypeFromConstructor: true
 
 	level: max
diff --git a/src/Exception/MaximumNumberNotGreaterThanZero.php b/src/Exception/MaximumNumberNotGreaterThanZero.php
new file mode 100644
index 00000000..c5497769
--- /dev/null
+++ b/src/Exception/MaximumNumberNotGreaterThanZero.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2021 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/phpunit-slow-test-detector
+ */
+
+namespace Ergebnis\PHPUnit\SlowTestDetector\Exception;
+
+final class MaximumNumberNotGreaterThanZero extends \InvalidArgumentException
+{
+    public static function create(int $value): self
+    {
+        return new self(\sprintf(
+            'Maximum number should be greater than 0, but %d is not.',
+            $value
+        ));
+    }
+}
diff --git a/src/SlowTestReporter.php b/src/SlowTestReporter.php
new file mode 100644
index 00000000..cbe50b65
--- /dev/null
+++ b/src/SlowTestReporter.php
@@ -0,0 +1,149 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2021 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/phpunit-slow-test-detector
+ */
+
+namespace Ergebnis\PHPUnit\SlowTestDetector;
+
+use PHPUnit\Event;
+
+final class SlowTestReporter
+{
+    private Comparator\DurationComparator $durationComparator;
+
+    private Event\Telemetry\DurationFormatter $durationFormatter;
+
+    private int $maximumNumber;
+
+    private Event\Telemetry\Duration $maximumDuration;
+
+    /**
+     * @throws Exception\MaximumNumberNotGreaterThanZero
+     */
+    public function __construct(
+        Event\Telemetry\DurationFormatter $durationFormatter,
+        Event\Telemetry\Duration $maximumDuration,
+        int $maximumNumber
+    ) {
+        if (0 >= $maximumNumber) {
+            throw Exception\MaximumNumberNotGreaterThanZero::create($maximumNumber);
+        }
+
+        $this->durationComparator = new Comparator\DurationComparator();
+        $this->durationFormatter = $durationFormatter;
+        $this->maximumDuration = $maximumDuration;
+        $this->maximumNumber = $maximumNumber;
+    }
+
+    public function report(SlowTest ...$slowTests): string
+    {
+        if ([] === $slowTests) {
+            return '';
+        }
+
+        $header = $this->header(...$slowTests);
+        $list = $this->list(...$slowTests);
+        $footer = $this->footer(...$slowTests);
+
+        return <<<TXT
+{$header}
+{$list}
+{$footer}
+TXT;
+    }
+
+    private function header(SlowTest ...$slowTests): string
+    {
+        $count = \count($slowTests);
+
+        $formattedMaximumDuration = $this->durationFormatter->format($this->maximumDuration);
+
+        return <<<TXT
+Detected {$count} tests that took longer than {$formattedMaximumDuration}.
+
+TXT;
+    }
+
+    private function list(SlowTest ...$slowTests): string
+    {
+        $durationComparator = $this->durationComparator;
+
+        \usort($slowTests, static function (SlowTest $one, SlowTest $two) use ($durationComparator): int {
+            return $durationComparator->compare(
+                $two->duration(),
+                $one->duration()
+            );
+        });
+
+        $slowTestsToReport = \array_slice(
+            $slowTests,
+            0,
+            $this->maximumNumber
+        );
+
+        /** @var SlowTest $slowestTest */
+        $slowestTest = \reset($slowTestsToReport);
+
+        $durationFormatter = $this->durationFormatter;
+
+        $width = \strlen($durationFormatter->format($slowestTest->duration()));
+
+        $items = \array_map(static function (SlowTest $slowTest) use ($durationFormatter, $width): string {
+            $label = \str_pad(
+                $durationFormatter->format($slowTest->duration()),
+                $width,
+                ' ',
+                \STR_PAD_LEFT
+            );
+
+            $test = $slowTest->test();
+
+            $testName = \sprintf(
+                '%s::%s',
+                $test->className(),
+                $test->methodNameWithDataSet()
+            );
+
+            return <<<TXT
+{$label}: {$testName}
+TXT;
+        }, $slowTestsToReport);
+
+        return \implode(
+            "\n",
+            $items
+        );
+    }
+
+    private function footer(SlowTest ...$slowTests): string
+    {
+        $remainingCount = \max(
+            \count($slowTests) - $this->maximumNumber,
+            0
+        );
+
+        if (0 === $remainingCount) {
+            return '';
+        }
+
+        if (1 === $remainingCount) {
+            return <<<'TXT'
+
+There is one additional slow test that is not listed here.
+TXT;
+        }
+
+        return <<<TXT
+
+There are {$remainingCount} additional slow tests that are not listed here.
+TXT;
+    }
+}
diff --git a/test/Fixture/ExampleTest.php b/test/Fixture/ExampleTest.php
new file mode 100644
index 00000000..cbe9a967
--- /dev/null
+++ b/test/Fixture/ExampleTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2021 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/phpunit-slow-test-detector
+ */
+
+namespace Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture;
+
+use PHPUnit\Framework;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+final class ExampleTest extends Framework\TestCase
+{
+}
diff --git a/test/Unit/Exception/MaximumNumberNotGreaterThanZeroTest.php b/test/Unit/Exception/MaximumNumberNotGreaterThanZeroTest.php
new file mode 100644
index 00000000..613a6289
--- /dev/null
+++ b/test/Unit/Exception/MaximumNumberNotGreaterThanZeroTest.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2021 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/phpunit-slow-test-detector
+ */
+
+namespace Ergebnis\PHPUnit\SlowTestDetector\Test\Unit\Exception;
+
+use Ergebnis\PHPUnit\SlowTestDetector\Exception\MaximumNumberNotGreaterThanZero;
+use Ergebnis\Test\Util;
+use PHPUnit\Framework;
+
+/**
+ * @internal
+ *
+ * @covers \Ergebnis\PHPUnit\SlowTestDetector\Exception\MaximumNumberNotGreaterThanZero
+ */
+final class MaximumNumberNotGreaterThanZeroTest extends Framework\TestCase
+{
+    use Util\Helper;
+
+    public function testCreareReturnsException(): void
+    {
+        $value = self::faker()->numberBetween();
+
+        $exception = MaximumNumberNotGreaterThanZero::create($value);
+
+        $message = \sprintf(
+            'Maximum number should be greater than 0, but %d is not.',
+            $value
+        );
+
+        self::assertSame($message, $exception->getMessage());
+    }
+}
diff --git a/test/Unit/SlowTestReporterTest.php b/test/Unit/SlowTestReporterTest.php
new file mode 100644
index 00000000..d2b50eb7
--- /dev/null
+++ b/test/Unit/SlowTestReporterTest.php
@@ -0,0 +1,448 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2021 Andreas Möller
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE.md file that was distributed with this source code.
+ *
+ * @see https://github.com/ergebnis/phpunit-slow-test-detector
+ */
+
+namespace Ergebnis\PHPUnit\SlowTestDetector\Test\Unit;
+
+use Ergebnis\PHPUnit\SlowTestDetector\Exception;
+use Ergebnis\PHPUnit\SlowTestDetector\Formatter\ToMillisecondsDurationFormatter;
+use Ergebnis\PHPUnit\SlowTestDetector\SlowTest;
+use Ergebnis\PHPUnit\SlowTestDetector\SlowTestReporter;
+use Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture;
+use Ergebnis\Test\Util;
+use PHPUnit\Event;
+use PHPUnit\Framework;
+
+/**
+ * @internal
+ *
+ * @covers \Ergebnis\PHPUnit\SlowTestDetector\SlowTestReporter
+ *
+ * @uses \Ergebnis\PHPUnit\SlowTestDetector\Comparator\DurationComparator
+ * @uses \Ergebnis\PHPUnit\SlowTestDetector\Exception\MaximumNumberNotGreaterThanZero
+ * @uses \Ergebnis\PHPUnit\SlowTestDetector\Formatter\ToMillisecondsDurationFormatter
+ * @uses \Ergebnis\PHPUnit\SlowTestDetector\SlowTest
+ */
+final class SlowTestReporterTest extends Framework\TestCase
+{
+    use Util\Helper;
+
+    /**
+     * @dataProvider \Ergebnis\Test\Util\DataProvider\IntProvider::lessThanZero()
+     * @dataProvider \Ergebnis\Test\Util\DataProvider\IntProvider::zero()
+     */
+    public function testConstructorRejectsMaximumCountLessThanOne(int $maximumCount): void
+    {
+        $faker = self::faker();
+
+        $durationFormatter = $this->createMock(Event\Telemetry\DurationFormatter::class);
+        $maximumDuration = Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+            $faker->numberBetween(),
+            $faker->numberBetween(0, 999999999)
+        );
+
+        $this->expectException(Exception\MaximumNumberNotGreaterThanZero::class);
+
+        new SlowTestReporter(
+            $durationFormatter,
+            $maximumDuration,
+            $maximumCount
+        );
+    }
+
+    public function testReportReturnsEmptyStringWhenNoSlowTestsHaveBeenSpecified(): void
+    {
+        $faker = self::faker();
+
+        $durationFormatter = $this->createMock(Event\Telemetry\DurationFormatter::class);
+        $maximumDuration = Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+            $faker->numberBetween(),
+            $faker->numberBetween(0, 999999999)
+        );
+        $maximumCount = $faker->numberBetween();
+
+        $slowTestReporter = new SlowTestReporter(
+            $durationFormatter,
+            $maximumDuration,
+            $maximumCount
+        );
+
+        $report = $slowTestReporter->report();
+
+        self::assertSame('', $report);
+    }
+
+    public function testReportReturnsReportWhenTheNumberOfSlowTestsIsSmallerThanTheMaximumCount(): void
+    {
+        $faker = self::faker();
+
+        $slowTests = [
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'foo',
+                    'foo with data set #123',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    7,
+                    890_123_456
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'bar',
+                    'bar',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    12,
+                    345_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'baz',
+                    'baz with dataset "string"',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    0,
+                    123_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'qux',
+                    'qux',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    3,
+                    456_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'quz',
+                    'quz',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    1,
+                    234_000_000
+                )
+            ),
+        ];
+
+        $durationFormatter = new ToMillisecondsDurationFormatter();
+
+        $maximumDuration = Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+            0,
+            100_000_000
+        );
+
+        $maximumNumber = $faker->numberBetween(\count($slowTests) + 1);
+
+        $slowTestReporter = new SlowTestReporter(
+            $durationFormatter,
+            $maximumDuration,
+            $maximumNumber
+        );
+
+        $report = $slowTestReporter->report(...$slowTests);
+
+        $expected = <<<'TXT'
+Detected 5 tests that took longer than 100 ms.
+
+12,345 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::bar
+ 7,890 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::foo with data set #123
+ 3,456 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::qux
+ 1,234 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::quz
+   123 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::baz with dataset "string"
+
+TXT;
+
+        self::assertSame($expected, $report);
+    }
+
+    public function testReportReturnsReportWhenTheNumberOfSlowTestsIsEqualToTheMaximumCount(): void
+    {
+        $slowTests = [
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'foo',
+                    'foo with data set #123',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    7,
+                    890_123_456
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'bar',
+                    'bar',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    12,
+                    345_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'baz',
+                    'baz with dataset "string"',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    0,
+                    123_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'qux',
+                    'qux',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    3,
+                    456_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'quz',
+                    'quz',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    1,
+                    234_000_000
+                )
+            ),
+        ];
+
+        $durationFormatter = new ToMillisecondsDurationFormatter();
+
+        $maximumDuration = Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+            0,
+            100_000_000
+        );
+
+        $maximumNumber = \count($slowTests);
+
+        $slowTestReporter = new SlowTestReporter(
+            $durationFormatter,
+            $maximumDuration,
+            $maximumNumber
+        );
+
+        $report = $slowTestReporter->report(...$slowTests);
+
+        $expected = <<<'TXT'
+Detected 5 tests that took longer than 100 ms.
+
+12,345 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::bar
+ 7,890 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::foo with data set #123
+ 3,456 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::qux
+ 1,234 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::quz
+   123 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::baz with dataset "string"
+
+TXT;
+
+        self::assertSame($expected, $report);
+    }
+
+    public function testReportReturnsReportWhenTheNumberOfSlowTestsIsOneMoreThanTheMaximumCount(): void
+    {
+        $slowTests = [
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'foo',
+                    'foo with data set #123',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    7,
+                    890_123_456
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'bar',
+                    'bar',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    12,
+                    345_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'baz',
+                    'baz with dataset "string"',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    0,
+                    123_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'qux',
+                    'qux',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    3,
+                    456_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'quz',
+                    'quz',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    1,
+                    234_000_000
+                )
+            ),
+        ];
+
+        $durationFormatter = new ToMillisecondsDurationFormatter();
+
+        $maximumDuration = Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+            0,
+            100_000_000
+        );
+
+        $maximumNumber = \count($slowTests) - 1;
+
+        $slowTestReporter = new SlowTestReporter(
+            $durationFormatter,
+            $maximumDuration,
+            $maximumNumber
+        );
+
+        $report = $slowTestReporter->report(...$slowTests);
+
+        $expected = <<<'TXT'
+Detected 5 tests that took longer than 100 ms.
+
+12,345 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::bar
+ 7,890 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::foo with data set #123
+ 3,456 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::qux
+ 1,234 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::quz
+
+There is one additional slow test that is not listed here.
+TXT;
+
+        self::assertSame($expected, $report);
+    }
+
+    public function testReportReturnsReportWhenTheNumberOfSlowTestsIsGreaterThanTheMaximumCountPlusOne(): void
+    {
+        $slowTests = [
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'foo',
+                    'foo with data set #123',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    7,
+                    890_123_456
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'bar',
+                    'bar',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    12,
+                    345_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'baz',
+                    'baz with dataset "string"',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    0,
+                    123_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'qux',
+                    'qux',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    3,
+                    456_000_000
+                )
+            ),
+            SlowTest::fromTestAndDuration(
+                new Event\Code\Test(
+                    Fixture\ExampleTest::class,
+                    'quz',
+                    'quz',
+                ),
+                Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+                    1,
+                    234_000_000
+                )
+            ),
+        ];
+
+        $durationFormatter = new ToMillisecondsDurationFormatter();
+
+        $maximumDuration = Event\Telemetry\Duration::fromSecondsAndNanoseconds(
+            0,
+            100_000_000
+        );
+
+        $maximumNumber = \count($slowTests) - 2;
+
+        $slowTestReporter = new SlowTestReporter(
+            $durationFormatter,
+            $maximumDuration,
+            $maximumNumber
+        );
+
+        $report = $slowTestReporter->report(...$slowTests);
+
+        $expected = <<<'TXT'
+Detected 5 tests that took longer than 100 ms.
+
+12,345 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::bar
+ 7,890 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::foo with data set #123
+ 3,456 ms: Ergebnis\PHPUnit\SlowTestDetector\Test\Fixture\ExampleTest::qux
+
+There are 2 additional slow tests that are not listed here.
+TXT;
+
+        self::assertSame($expected, $report);
+    }
+}