StatusWriter: add protection against resuming > pausing

Includes test.

Author: jrfnl

src/Util/Writers/StatusWriter.php

@@ -118,7 +118,10 @@ public static function pause()
      */
     public static function resume()
     {
-        --self::$pauseCount;
+        if (self::$pauseCount > 0) {
+            --self::$pauseCount;
+        }
+
         if (self::$pauseCount === 0) {
             self::$paused = false;
         }

tests/Core/Util/Writers/StatusWriterTest.php

@@ -304,4 +304,60 @@ public function testNestedPausing()
     }//end testNestedPausing()
 
 
+    /**
+     * Verify that resuming more often than the StatusWriter is paused, won't block future pauses.
+     *
+     * @return void
+     */
+    public function testResumingMoreOftenThanPaused()
+    {
+        $this->expectNoStdoutOutput();
+
+        $messageA = 'This message should not be printed when the StatusWriter is paused';
+        $messageB = 'Once the StatusWriter is resumed, messages should be printed again';
+        $expected = $messageB.PHP_EOL.$messageB.PHP_EOL;
+
+        $this->assertFalse(StatusWriter::isPaused());
+
+        // Pause 1.
+        StatusWriter::pause();
+        $this->assertTrue(StatusWriter::isPaused());
+
+        StatusWriter::write($messageA);
+
+        // Pause 2.
+        StatusWriter::pause();
+        $this->assertTrue(StatusWriter::isPaused());
+
+        StatusWriter::write($messageA);
+
+        // Resume 2.
+        StatusWriter::resume();
+        $this->assertTrue(StatusWriter::isPaused());
+
+        StatusWriter::write($messageA);
+
+        // Resume 1.
+        StatusWriter::resume();
+        $this->assertFalse(StatusWriter::isPaused());
+
+        StatusWriter::write($messageB);
+
+        // Resume too much - this resume should not change the pause counter.
+        StatusWriter::resume();
+        $this->assertFalse(StatusWriter::isPaused());
+
+        StatusWriter::write($messageB);
+
+        // Pause after "resume too much", still pauses the StatusWriter.
+        StatusWriter::pause();
+        $this->assertTrue(StatusWriter::isPaused());
+
+        StatusWriter::write($messageA);
+
+        $this->assertStderrOutputSameString($expected);
+
+    }//end testResumingMoreOftenThanPaused()
+
+
 }//end class