Split memory string formatting into a separate class (#4)

.gitignore

@@ -1,3 +1,4 @@
 .idea
 composer.lock
 vendor
+.phpunit.result.cache

phpunit.xml.dist

@@ -7,7 +7,7 @@
         <directory>tests</directory>
     </testsuite>
     <extensions>
-        <extension class="MOJ\PHPUnit\MemoryUsageHook">
+        <extension class="MinistryOfJustice\PHPUnit\MemoryUsageHook">
             <arguments>
                 <integer>500000</integer>
                 <boolean>true</boolean>

src/MemoryStringFormatter.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MinistryOfJustice\PHPUnit;
+
+class MemoryStringFormatter
+{
+    public static function roundToStandardUnits(int $bytes): string
+    {
+        $unit = ['B','KB','MB','GB'];
+
+        $magnitude = floor(log($bytes, 1024));
+        $value = round($bytes / pow(1024, $magnitude), 2);
+
+        return $value . ' ' . $unit[$magnitude];
+    }
+}

src/MemoryUsageHook.php

@@ -19,12 +19,6 @@ public function __construct(
     ) {
     }
 
-    static function roundToStandardUnits($size): string
-    {
-        $unit=['B','KB','MB','GB'];
-        return round($size/pow(1024,($i=floor(log($size,1024)))),2) . ' ' . $unit[$i];
-    }
-
     public function executeBeforeTest(string $test): void
     {
         $this->previousUsage = memory_get_usage();
@@ -40,8 +34,8 @@ public function executeAfterTest(string $test, float $time): void
         }
 
         if ($this->displayRunningTotal) {
-            $currentString = self::roundToStandardUnits($currentUsage);
-            $differenceString = self::roundToStandardUnits($difference);
+            $currentString = MemoryStringFormatter::roundToStandardUnits($currentUsage);
+            $differenceString = MemoryStringFormatter::roundToStandardUnits($difference);
             print("Test '$test' ended. Current: $currentString, Difference: $differenceString\n");
         }
     }
@@ -59,7 +53,7 @@ public function executeAfterLastTest(): void
         array_multisort($usageColumn, SORT_DESC, $this->results);
 
         foreach ($this->results as $result) {
-            $differenceString = self::roundToStandardUnits($result['usage']);
+            $differenceString = MemoryStringFormatter::roundToStandardUnits($result['usage']);
             print("Test '${result['name']}' used: $differenceString\n");
         }
     }

tests/MemoryStringFormatterTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MinistryOfJustice\PHPUnit\Tests;
+
+use MinistryOfJustice\PHPUnit\MemoryStringFormatter;
+use PHPUnit\Framework\TestCase;
+
+class MemoryStringFormatterTest extends TestCase
+{
+    /**
+     * @dataProvider memoryProvider
+     */
+    public function test_roundToStandardUnits(string $expectedValue, int $bytes): void
+    {
+        $this->assertEquals($expectedValue, MemoryStringFormatter::roundToStandardUnits($bytes));
+    }
+
+    public function memoryProvider(): array
+    {
+        return [
+            '1 Byte' => ['1 B', 1],
+            'Maximum Bytes' => ['1023 B', 1023],
+            '1 Kilobyte' => ['1 KB', 1024],
+            'Maximum Kilobytes' => ['1024 KB', 1048575],
+            '1 Megabyte' => ['1 MB', 1048576],
+            'Maximum Megabytes' => ['1024 MB', 1073741823],
+            '1 Gigabyte' => ['1 GB', 1073741824],
+            '1024 Gigabytes' => ['1024 GB', 1099511627775],
+        ];
+    }
+}