use phpstan/phpstan-phpunit for mocks

.travis.yml

@@ -72,7 +72,9 @@ script:
   - if [[ $DEFAULT = 1 && $TRAVIS_PHP_VERSION != 7.0 ]]; then vendor/bin/phpunit; fi
 
   - if [[ $PHPCS = 1 ]]; then composer cs-check; fi
-  - if [[ $PHPSTAN = 1 ]]; then composer require --dev "phpstan/phpstan:0.9.*" && vendor/bin/phpstan analyse -c phpstan.neon -l 2 src; fi
+  - if [[ $PHPSTAN = 1 ]]; then composer require --dev "phpstan/phpstan:0.9.*" ; fi
+  - if [[ $PHPSTAN = 1 ]]; then composer require --dev "phpstan/phpstan-phpunit:0.9.*" ; fi
+  - if [[ $PHPSTAN = 1 ]]; then vendor/bin/phpstan analyse -c phpstan.neon -l 2 src; fi
 
 after_success:
   - if [[ $DEFAULT = 1 && $TRAVIS_PHP_VERSION = 7.0 ]]; then bash <(curl -s https://codecov.io/bash); fi

phpstan.neon

@@ -1,3 +1,6 @@
+includes:
+    - vendor/phpstan/phpstan-phpunit/extension.neon
+
 parameters:
     autoload_files:
         - tests/bootstrap.php