add GherkinParamNullableTest

tests/unit/GherkinParamNullableTest.php

@@ -0,0 +1,42 @@
+<?php
+
+class GherkinParamNullableTest extends \Codeception\Test\Unit
+{
+
+    /**
+     * @var \UnitTester
+     */
+    protected $module;
+
+    protected function _before(): void
+    {        
+        $module = $this->getModule('Codeception\Extension\GherkinParam');
+        $module->_reconfigure(
+            [
+            'onErrorThrowException' => false, 
+            'onErrorNull' => true
+            ]
+        );
+        $this->module = Mockery::spy($module)
+            ->shouldAllowMockingProtectedMethods();
+    }
+
+    protected function _after(): void
+    {
+    }
+
+    public function testMapParametersToValuesWithExceptionOnIsArray()
+    {
+
+
+        $param = $this
+            ->module
+            ->mapParametersToValues(
+                [0,1,2,3,4],
+                [],
+                "test"
+            );
+
+        $this->assertNull($param);
+    }
+}