Add coverage information to tests, fix coverage of NodaValidationHelper

tests/NodaValidationHelperTest.php

@@ -9,8 +9,24 @@ use PHPUnit\Framework\TestCase;
 
 /**
  * This script contains tests for the validation of single field contents.
+ *
+ * @covers \NodaValidationHelper
  */
 final class NodaValidationHelperTest extends TestCase {
+    /**
+     * Test that a specific error is thrown if no description for actors is provided.
+     *
+     * @small
+     *
+     * @return void
+     */
+    public function testActorDescriptionValidationFailsOnEmptyInput():void {
+
+        $this->expectException(MDInvalidEmptyInputException::class);
+        NodaValidationHelper::validateActorDescription("");
+
+    }
+
     /**
      * Test successfully refusing too short actor descriptions.
      *