run mutation testing in CI

.travis.yml

@@ -8,21 +8,21 @@ php:
 
 dist: trusty
 
-before_install:
-  - composer selfupdate
-
 install:
   - composer install --prefer-source --dev
+  - wget https://github.com/infection/infection/releases/download/0.7.0/infection.phar
+  - wget https://github.com/infection/infection/releases/download/0.7.0/infection.phar.pubkey
+  - chmod +x infection.phar
 
 script:
   - php vendor/bin/phpunit
-  - vendor/bin/phpstan analyze -l 4 src tests examples
   - php vendor/bin/phpcs -n --standard=PSR1,PSR2 --report=full src/ tests/ examples/
+  - if [ "$TRAVIS_PHP_VERSION" != "nightly" ]; then php infection.phar --min-msi=75 --min-covered-msi=75 --threads=4; fi
+  - php vendor/bin/phpstan analyze -l 4 src tests examples
   - ./validate_examples.sh
 
 after_success:
-  - wget https://scrutinizer-ci.com/ocular.phar
-  - sh -c 'if [ "$TRAVIS_PHP_VERSION" != "hhvm" ] && [ "$TRAVIS_PHP_VERSION" != "nightly" ]; then php ocular.phar code-coverage:upload --format=php-clover build/docs/clover.xml; fi;'
+  - if [ "$TRAVIS_PHP_VERSION" != "nightly" ]; then php ocular.phar code-coverage:upload --format=php-clover build/docs/clover.xml; fi
 
 matrix:
     fast_finish: true

infection.json.dist

@@ -0,0 +1,11 @@
+{
+    "timeout": 10,
+    "source": {
+        "directories": [
+            "src"
+        ]
+    },
+    "logs": {
+        "text": "infection-log.txt"
+    }
+}

tests/Types/IntegerBitSizeTest.php

@@ -2,7 +2,6 @@
 
 namespace BitWasp\Buffertools\Tests\Types;
 
-
 use BitWasp\Buffertools\Tests\BinaryTest;
 use BitWasp\Buffertools\Types\Int128;
 use BitWasp\Buffertools\Types\Int16;
@@ -44,7 +43,8 @@ public function getClassAndBitSize()
      * @param string $integerClass
      * @param int $bitSize
      */
-    public function testBitSize(string $integerClass, int $bitSize) {
+    public function testBitSize(string $integerClass, int $bitSize)
+    {
         /** @var UintInterface|SignedIntInterface $integer */
         $integer = new $integerClass();
         $this->assertEquals($bitSize, $integer->getBitSize());