Rework tests structure. Upgrade codeception to 2.5.3. Merge params configuration into app configuration.

common/tests/helpers/Mock.php

@@ -0,0 +1,24 @@
+<?php
+declare(strict_types=1);
+namespace common\tests\helpers;
+
+use phpmock\mockery\PHPMockery;
+use ReflectionClass;
+
+class Mock {
+
+    /**
+     * @param string $className
+     * @param string $function
+     *
+     * @return \Mockery\Expectation
+     */
+    public static function func(string $className, string $function) {
+        return PHPMockery::mock(self::getClassNamespace($className), $function);
+    }
+
+    private static function getClassNamespace(string $className): string {
+        return (new ReflectionClass($className))->getNamespaceName();
+    }
+
+}