Fix size diff check - issue #182

Some time ago the collectors where changed to return the current backup
as well. That change was never reflected withing the size diff check.
So the size diff check always checked the size difference against the
current backup, which resulted in 0% change all the time.

Author: sebastianfeldmann

src/Backup/Check/SizeDiffPreviousPercent.php

@@ -34,27 +34,31 @@ class SizeDiffPreviousPercent implements Simulator
      */
     public function pass(Target $target, $value, Local $collector, Result $result) : bool
     {
+        $result->debug('checking size difference ' . $value . '%' . PHP_EOL);
+
         // throws App\Exception if file doesn't exist
         $backupSize   = $target->getSize();
         $history      = $collector->getBackupFiles();
         $historyCount = count($history);
         $pass         = true;
 
-        if ($historyCount > 0) {
-            // oldest backups first
-            ksort($history);
-            $prevFile    = array_pop($history);
-            $prevSize    = $prevFile->getSize();
-            $diffPercent = Math::getDiffInPercent($backupSize, $prevSize);
+        if ($historyCount > 1) {
+            // latest backups first
+            krsort($history);
+            // grab the second backup in the history as it should be the previous one
+            $previousBackup = $history[array_keys($history)[1]];
+            $prevSize       = $previousBackup->getSize();
+            $diffPercent    = Math::getDiffInPercent($backupSize, $prevSize);
 
+            $result->debug('size difference is ' . $diffPercent . '%' . PHP_EOL);
             $pass = $diffPercent < $value;
         }
 
         return $pass;
     }
 
     /**
-     * Simulate the check execution.
+     * Simulate the check execution
      *
      * @param  \phpbu\App\Backup\Target          $target
      * @param  string                            $value

tests/phpbu/Backup/Check/SizeDiffPreviousPercentTest.php

@@ -1,6 +1,10 @@
 <?php
 namespace phpbu\App\Backup\Check;
 
+use phpbu\App\Backup\Collector\Local;
+use phpbu\App\Backup\Target;
+use phpbu\App\Result;
+
 /**
  * SizeDiffPreviousPercentTest
  *
@@ -19,19 +23,19 @@ class SizeDiffPreviousPercentTest extends \PHPUnit\Framework\TestCase
      */
     public function testPass()
     {
-        $resultStub    = $this->createMock(\phpbu\App\Result::class);
-        $collectorStub = $this->createMock(\phpbu\App\Backup\Collector\Local::class);
+        $resultStub    = $this->createMock(Result::class);
+        $collectorStub = $this->createMock(Local::class);
         $collectorStub->expects($this->once())
                       ->method('getBackupFiles')
-                      ->willReturn($this->getFileListMock([100, 500, 1000]));
-        $targetStub    = $this->createMock(\phpbu\App\Backup\Target::class);
+                      ->willReturn($this->getFileListMock([100, 500, 1000, 1060]));
+        $targetStub    = $this->createMock(Target::class);
         $targetStub->method('getSize')->willReturn(1060);
 
         $check = new SizeDiffPreviousPercent();
 
         $this->assertTrue(
             $check->pass($targetStub, '10', $collectorStub, $resultStub),
-            'size of stub should be about 900 -  1100'
+            'size of 1060 should be in range of 900 -  1100'
         );
     }
 
@@ -40,19 +44,19 @@ public function testPass()
      */
     public function testFail()
     {
-        $resultStub    = $this->createMock(\phpbu\App\Result::class);
-        $collectorStub = $this->createMock(\phpbu\App\Backup\Collector\Local::class);
+        $resultStub    = $this->createMock(Result::class);
+        $collectorStub = $this->createMock(Local::class);
         $collectorStub->expects($this->once())
                       ->method('getBackupFiles')
-                      ->willReturn($this->getFileListMock([100, 500, 1000]));
-        $targetStub    = $this->createMock(\phpbu\App\Backup\Target::class);
+                      ->willReturn($this->getFileListMock([100, 500, 1000, 1060]));
+        $targetStub    = $this->createMock(Target::class);
         $targetStub->method('getSize')->willReturn(1060);
 
         $check = new SizeDiffPreviousPercent();
 
         $this->assertFalse(
             $check->pass($targetStub, '5', $collectorStub, $resultStub),
-            'size of stub should be about 900 -  1100'
+            'size of 1060 should not be in rage of 950 - 1050'
         );
     }
 
@@ -61,9 +65,9 @@ public function testFail()
      */
     public function testSimulate()
     {
-        $collectorStub = $this->createMock(\phpbu\App\Backup\Collector\Local::class);
-        $targetStub    = $this->createMock(\phpbu\App\Backup\Target::class);
-        $resultStub    = $this->createMock(\phpbu\App\Result::class);
+        $collectorStub = $this->createMock(Local::class);
+        $targetStub    = $this->createMock(Target::class);
+        $resultStub    = $this->createMock(Result::class);
         $resultStub->expects($this->once())->method('debug');
 
         $check = new SizeDiffPreviousPercent();