Tests layout

.gitignore

@@ -1 +1,4 @@
+vendor
+wordpress-develop
 *.swp
+composer.lock

README.md

@@ -10,7 +10,7 @@ Consider the following user balance topup function that is susceptible to a race
 
 ```php
 // A thread-safe version of the above topup function.
-public function topup_user_balance( $topup ) {
+public function topup_user_balance( $user_id, $topup ) {
 	$balance = get_user_meta( $user_id, 'balance', true );
 	$balance = $balance + $topup;
 	update_user_meta( $user_id, 'balance', $balance = get_user_meta( $user_id, 'balance', true ) + $topup );
@@ -22,7 +22,7 @@ Try to call the above code 100 times in 16 threads. The balance will be less tha
 
 ```php
 // A thread-safe version of the above topup function.
-public function topup_user_balance( $topup ) {
+public function topup_user_balance( $user_id, $topup ) {
 	$user_balance_lock = new WP_Lock( "$user_id:meta:balance" );
 	$user_balance_lock->acquire( WP_Lock::EXCLUSIVE );
 

composer.json

@@ -0,0 +1,5 @@
+{
+    "require-dev": {
+        "phpunit/phpunit": "^6"
+    }
+}

phpunit.xml.dist

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit
+	bootstrap="tests/bootstrap.php"
+	backupGlobals="false"
+	colors="true"
+	convertErrorsToExceptions="true"
+	convertNoticesToExceptions="true"
+	convertWarningsToExceptions="true"
+	verbose="true"
+	>
+	<php>
+		<const name="DOING_TESTS" value="1" />
+	</php>
+	<testsuites>
+		<testsuite name="WP_Lock concurrency mutexes for WordPress test suite">
+			<directory suffix=".php">tests/lock</directory>
+		</testsuite>
+	</testsuites>
+	<filter>
+		<whitelist processUncoveredFilesFromWhitelist="false">
+			<directory suffix=".php">.</directory>
+			<exclude>
+				<directory>tests</directory>
+				<directory>vendor</directory>
+				<directory>wordpress-develop</directory>
+			</exclude>
+		</whitelist>
+	</filter>
+	<logging>
+		<log type="coverage-clover" target="/tmp/clover.xml" charset="UTF-8" />
+	</logging>
+</phpunit>

tests/bootstrap.php

@@ -0,0 +1,10 @@
+<?php
+$test_root = getenv( 'WP_TESTS_DIR' ) ? : dirname( __FILE__ ) . '/../wordpress-develop/tests/phpunit';
+
+require $test_root . '/includes/bootstrap.php';
+
+function _manually_load_plugin() {
+	require dirname( __FILE__ ) . '/../plugin.php';
+}
+
+tests_add_filter( 'muplugins_loaded', '_manually_load_plugin' );

tests/lock/flock.php

@@ -0,0 +1,6 @@
+<?php
+class WP_Lock_Backend_flock_UnitTestCase extends WP_UnitTestCase {
+	public function test_true() {
+		$this->assertTrue( true );
+	}
+}