Enable Psalm static code analysis for PHPUnit tests

Author: PhrozenByte

composer.json

@@ -34,6 +34,8 @@
     "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>

tests/TestCase.php

@@ -146,6 +146,8 @@ public function assertCallableThrowsNot(
      * method. It e.g. doesn't incorporates a Closure's scope, but works for
      * testing `PHPUnitThrowableAsserts`.
      *
+     * @psalm-suppress RedundantCondition
+     *
      * @param callable $callable the Callable to describe
      *
      * @return string string representation of the Callable

tests/Unit/CachedCallableProxyTest.php

@@ -52,6 +52,8 @@ public function testSelfDescribing(
     }
 
     /**
+     * @psalm-suppress NullArgument
+     *
      * @return array
      */
     public function dataProviderSelfDescribing(): array

tests/Unit/CallableProxyTest.php

@@ -52,6 +52,8 @@ public function testSelfDescribing(
     }
 
     /**
+     * @psalm-suppress NullArgument
+     *
      * @return array
      */
     public function dataProviderSelfDescribing(): array

tests/Unit/ThrowableAssertsTraitTest.php

@@ -98,6 +98,7 @@ public function testAssertCallableThrows(
         array $callableExceptionData
     ): void {
         $callable = static function () use ($callableExceptionData) {
+            /** @psalm-var class-string<Throwable> $className */
             $className = array_shift($callableExceptionData);
             throw new $className(...$callableExceptionData);
         };

tests/Utils/InvocableClass.php

@@ -56,6 +56,7 @@ public function __construct(string $throwableClassName = null, ...$throwableArgu
     public function __invoke(...$arguments): array
     {
         if ($this->throwableClassName !== null) {
+            /** @psalm-var class-string<Throwable> $className */
             $className = $this->throwableClassName;
             throw new $className(...$this->throwableArguments);
         }