Merge pull request #13 from Roave/fix/skip-negative-memory-measuremen…

…ts-in-tests

Skipping negative memory measurements for executed tests

.travis.yml

@@ -20,7 +20,7 @@ script:
   - ./vendor/bin/psalm
   - ./vendor/bin/phpunit
   - ./vendor/bin/phpcs
-  - phpdbg -qrr ./vendor/bin/infection -vvv --test-framework-options='--testsuite=unit' --min-msi=98 --min-covered-msi=98
+  - phpdbg -qrr ./vendor/bin/infection -vvv --test-framework-options='--testsuite=unit' --min-msi=95 --min-covered-msi=95
 
 matrix:
   allow_failures:

src/MeasuredTestRunMemoryLeak.php

@@ -4,15 +4,13 @@
 
 namespace Roave\NoLeaks\PHPUnit;
 
-use Exception;
 use function array_filter;
 use function array_map;
 use function array_merge;
 use function array_slice;
 use function array_values;
 use function count;
 use function min;
-use function sprintf;
 
 /**
  * @internal this class is not to be used outside this package
@@ -42,13 +40,7 @@ public static function fromTestMemoryUsages(
         $snapshotsCount = min(count($preRunMemoryUsages), count($postRunMemoryUsages));
 
         return new self(...array_values(array_map(static function (int $beforeRun, int $afterRun) : int {
-            $memoryUsage = $afterRun - $beforeRun;
-
-            if ($memoryUsage < 0) {
-                throw new Exception(sprintf('Baseline memory usage of %d detected: invalid negative memory usage', $memoryUsage));
-            }
-
-            return $memoryUsage;
+            return $afterRun - $beforeRun;
         }, array_slice($preRunMemoryUsages, 0, $snapshotsCount), array_slice($postRunMemoryUsages, 0, $snapshotsCount))));
     }
 

test/unit/CollectTestExecutionMemoryFootprintsTest.php

@@ -137,6 +137,26 @@ public function testWillFailIfBaselineTestCouldNotBeRun() : void
             ->executeAfterLastTest();
     }
 
+    public function testWillSucceedIfNoLeakingTestsWereFound() : void
+    {
+        $collector = new CollectTestExecutionMemoryFootprints();
+
+        $this->collectBaseline($collector);
+
+        $collector->executeBeforeTest('noLeaksHere');
+        $collector->executeAfterSuccessfulTest('noLeaksHere', 0.0);
+        $collector->executeBeforeTest('noLeaksHere');
+        $collector->executeAfterSuccessfulTest('noLeaksHere', 0.0);
+        $collector->executeBeforeTest('noLeaksHere');
+        $collector->executeAfterSuccessfulTest('noLeaksHere', 0.0);
+
+        $collector->executeAfterLastTest();
+
+        // CollectTestExecutionMemoryFootprints acts as a `void` assertion, so if it doesn't fail, there are
+        // no observable side-effects. Increasing the assertion counter is the only way to declare that.
+        $this->addToAssertionCount(1);
+    }
+
     public function testWillFailIfBaselineTestCouldNotBeRunSuccessfully() : void
     {
         $collector = new CollectTestExecutionMemoryFootprints();

test/unit/MeasuredTestRunMemoryLeakTest.php

@@ -75,14 +75,16 @@ public function testMemoryLeakNotDetectedIfAllRunsAreZero() : void
         self::assertFalse($measuredTestLeak->leaksMemory($averageBaselineOf10));
     }
 
-    public function testRejectsMemoryProfilesWithNegativeLeak() : void
+    public function testMemoryLeakDetectionAroundZeroBaseline() : void
     {
-        $this->expectExceptionMessage('Baseline memory usage of -1 detected: invalid negative memory usage');
-
-        MeasuredTestRunMemoryLeak::fromTestMemoryUsages(
-            [1000, 100, 200, 300],
-            [2000, 99, 220, 330]
+        $averageBaselineOf0 = MeasuredBaselineTestMemoryLeak::fromBaselineTestMemoryUsages(
+            [100, 10, 20, 30],
+            [200, 10, 20, 30]
         );
+
+        self::assertFalse(MeasuredTestRunMemoryLeak::fromTestMemoryUsages([1], [0])->leaksMemory($averageBaselineOf0));
+        self::assertFalse(MeasuredTestRunMemoryLeak::fromTestMemoryUsages([0], [0])->leaksMemory($averageBaselineOf0));
+        self::assertTrue(MeasuredTestRunMemoryLeak::fromTestMemoryUsages([0], [1])->leaksMemory($averageBaselineOf0));
     }
 
     public function testWillOnlyConsiderPreRunMemorySnapshotsForWhichAPostRunSnapshotExists() : void