From 7563926255041774a2a7cb103d83f17d2bfe33a7 Mon Sep 17 00:00:00 2001
From: Alexey Kopytko <alexey@kopytko.com>
Date: Sat, 11 Sep 2021 20:39:12 +0900
Subject: [PATCH 1/3] Use smaller epsilon and relative error for float
 comparison

Fixes #1537
---
 .../JUnit/TestLocationBucketSorterTest.php     | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php b/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
index 442ef7200..9b4af0f80 100644
--- a/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
+++ b/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
@@ -189,7 +189,7 @@ public function test_it_sorts_faster_than_quicksort(ArrayIterator $uniqueTestLoc
             $totalQuickSort += microtime(true) - $start;
         }
 
-        $this->assertGreaterThanOrEqual(0.01, abs($totalQuickSort - $totalBucketSort));
+        $this->assertGreaterThanOrEqual(0.001, self::getRelativeError($totalQuickSort, $totalBucketSort));
     }
 
     public static function locationsArrayProvider(): iterable
@@ -206,6 +206,22 @@ static function (float $executionTime): TestLocation {
         yield 'All locations' => [new ArrayIterator($locations)];
     }
 
+    /**
+     * Finds relative error.
+     *
+     * @see https://floating-point-gui.de/errors/comparison/
+     * @see https://stackoverflow.com/questions/4915462/how-should-i-do-floating-point-comparison
+     */
+    private static function getRelativeError(float $a, float $b): float
+    {
+        // We do not expect A or B to be extremely small or large: these are edge cases,
+        // and they will need special handling which we avoid simplicity sake.
+        self::assertGreaterThan(0.0001, abs($a));
+        self::assertGreaterThan(0.0001, abs($b));
+
+        return abs($a - $b) / (abs($a) + abs($b));
+    }
+
     private static function quicksort(&$uniqueTestLocations): void
     {
         usort(

From 5244bf7f8b501f37dcc7d040ff9c0da815506a87 Mon Sep 17 00:00:00 2001
From: Alexey Kopytko <alexey@kopytko.com>
Date: Sat, 11 Sep 2021 20:42:30 +0900
Subject: [PATCH 2/3] Use common epsilon here and there

---
 .../Coverage/JUnit/TestLocationBucketSorterTest.php       | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php b/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
index 9b4af0f80..973330403 100644
--- a/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
+++ b/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
@@ -59,6 +59,8 @@
  */
 final class TestLocationBucketSorterTest extends TestCase
 {
+    private const EPSILON = 0.001;
+
     public function test_it_sorts(): void
     {
         $testLocation = new TestLocation('', '', 0.0);
@@ -189,7 +191,7 @@ public function test_it_sorts_faster_than_quicksort(ArrayIterator $uniqueTestLoc
             $totalQuickSort += microtime(true) - $start;
         }
 
-        $this->assertGreaterThanOrEqual(0.001, self::getRelativeError($totalQuickSort, $totalBucketSort));
+        $this->assertGreaterThanOrEqual(self::EPSILON, self::getRelativeError($totalQuickSort, $totalBucketSort));
     }
 
     public static function locationsArrayProvider(): iterable
@@ -216,8 +218,8 @@ private static function getRelativeError(float $a, float $b): float
     {
         // We do not expect A or B to be extremely small or large: these are edge cases,
         // and they will need special handling which we avoid simplicity sake.
-        self::assertGreaterThan(0.0001, abs($a));
-        self::assertGreaterThan(0.0001, abs($b));
+        self::assertGreaterThan(self::EPSILON, abs($a));
+        self::assertGreaterThan(self::EPSILON, abs($b));
 
         return abs($a - $b) / (abs($a) + abs($b));
     }

From 62811fb1660a6d7d13cdf137a114627b04e9ccd7 Mon Sep 17 00:00:00 2001
From: Alexey Kopytko <alexey@kopytko.com>
Date: Sat, 11 Sep 2021 20:44:02 +0900
Subject: [PATCH 3/3] Document the constant

---
 .../Coverage/JUnit/TestLocationBucketSorterTest.php          | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php b/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
index 973330403..61aa11ecf 100644
--- a/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
+++ b/tests/phpunit/TestFramework/Coverage/JUnit/TestLocationBucketSorterTest.php
@@ -59,6 +59,11 @@
  */
 final class TestLocationBucketSorterTest extends TestCase
 {
+    /**
+     * Used for floating point comparisons.
+     *
+     * @var float
+     */
     private const EPSILON = 0.001;
 
     public function test_it_sorts(): void