Enable Psalm static code analysis for PHPUnit tests

Author: PhrozenByte

composer.json

@@ -36,6 +36,8 @@
     "require-dev": {
         "php-parallel-lint/php-parallel-lint": "^1.2",
         "vimeo/psalm": "^4.5",
+        "psalm/plugin-phpunit": "^0.15.1",
+        "psalm/plugin-mockery": "^0.7.0",
         "phpunit/phpunit": "^8",
         "mockery/mockery": "^1.3",
         "symfony/yaml": "^4.4",

psalm.xml

@@ -22,13 +22,18 @@
     xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
 >
     <projectFiles>
-        <directory name="src" />
+        <directory name="src"/>
+        <directory name="tests"/>
         <ignoreFiles>
             <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
     <issueHandlers>
-        <InternalClass errorLevel="suppress" />
-        <InternalMethod errorLevel="suppress" />
+        <InternalClass errorLevel="suppress"/>
+        <InternalMethod errorLevel="suppress"/>
     </issueHandlers>
+    <plugins>
+        <pluginClass class="Psalm\PhpUnitPlugin\Plugin"/>
+        <pluginClass class="Psalm\MockeryPlugin\Plugin"/>
+    </plugins>
 </psalm>