Sample test

.idea/php-test-framework.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="PhpTestFrameworkVersionCache">
+    <tools_cache>
+      <tool tool_name="PHPUnit">
+        <cache>
+          <versions>
+            <info id="Local" version="6.5.13" />
+          </versions>
+        </cache>
+      </tool>
+    </tools_cache>
+  </component>
+</project>

.idea/php.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="PhpProjectSharedConfiguration" php_language_level="7.1" />
+  <component name="PhpUnit">
+    <phpunit_settings>
+      <PhpUnitSettings load_method="PHPUNIT_PHAR" custom_loader_path="" phpunit_phar_path="$PROJECT_DIR$/../php-7.3.0-Win32-VC15-x64/phpunit-6.5.13.phar" />
+    </phpunit_settings>
+  </component>
+</project>

src/entryPoint.php

@@ -10,7 +10,7 @@ define("INTER_ROOM", 111213);
 
 // randomorg($start,$end);
 
-function reply_user($room_id, $msgid, $message)
+function reply_user($room_id, $msgid, $message) : string
 {
     return $msgid;
 }

test/Test.php

@@ -0,0 +1,21 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: Brian
+ * Date: 19/12/2018
+ * Time: 21:00
+ */
+
+use PHPUnit\Framework\TestCase;
+require '../src/entryPoint.php';
+
+class Test extends TestCase
+{
+    public function testShouldReturnMessageID(): void
+    {
+        $this->assertEquals(
+            '0',
+            reply_user('whatever', 0, 'whatever')
+        );
+    }
+}