Add integration tests folder with a proof-of-concept test

phpunit-integration.xml.dist

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/7.5/phpunit.xsd"
+	backupGlobals="false"
+	backupStaticAttributes="false"
+	bootstrap="tests/integration/bootstrap.php"
+	colors="true"
+	convertDeprecationsToExceptions="true"
+	convertErrorsToExceptions="true"
+	convertNoticesToExceptions="true"
+	convertWarningsToExceptions="true"
+	forceCoversAnnotation="true"
+	processIsolation="false"
+	stopOnError="false"
+	stopOnFailure="false"
+	stopOnIncomplete="false"
+	stopOnSkipped="false"
+	verbose="true"
+	>
+	<testsuites>
+		<testsuite name="duplicatepost">
+			<directory suffix="-test.php">./tests/integration</directory>
+		</testsuite>
+	</testsuites>
+
+	<filter>
+		<whitelist addUncoveredFilesFromWhitelist="true" processUncoveredFilesFromWhitelist="false">
+			<file>./admin-functions.php</file>
+			<file>./common-functions.php</file>
+			<file>./duplicate-post.php</file>
+			<file>./options.php</file>
+			<directory>./compat</directory>
+			<directory>./src</directory>
+		</whitelist>
+	</filter>
+
+	<logging>
+		<log type="coverage-text" target="php://stdout" showOnlySummary="true"/>
+		<log type="coverage-clover" target="build/logs/clover-integration.xml"/>
+	</logging>
+
+</phpunit>

tests/integration/bootstrap.php

@@ -0,0 +1,73 @@
+<?php
+/**
+ * Yoast Duplicate Post plugin test file.
+ *
+ * @package Yoast\WP\Duplicate_Post\Tests
+ */
+
+use Yoast\WPTestUtils\WPIntegration;
+
+// Disable xdebug backtrace.
+if ( function_exists( 'xdebug_disable' ) ) {
+	xdebug_disable();
+}
+
+echo 'Welcome to the Duplicate Post Test Suite' . PHP_EOL;
+echo 'Version: 1.0' . PHP_EOL . PHP_EOL;
+
+/*
+ * Set up info needed for checking the status of a GitHub issue.
+ */
+$GLOBALS['github_repo'] = [
+	'name'         => 'Yoast Duplicate Post',
+	'organisation' => 'Yoast',
+	'repo_slug'    => 'duplicate-post',
+	'api_key'      => false,
+	'private'      => true,
+];
+
+if ( getenv( 'GITHUB_API_KEY' ) !== false ) {
+	$GLOBALS['github_repo']['api_key'] = getenv( 'GITHUB_API_KEY' );
+}
+
+if ( ! defined( 'WP_TESTS_FORCE_KNOWN_BUGS' ) ) {
+	define( 'WP_TESTS_FORCE_KNOWN_BUGS', ( getenv( 'WP_TESTS_FORCE_KNOWN_BUGS' ) === '1' ) );
+}
+
+if ( ! defined( 'YOAST_DUPLICATE_POST_TEST_ROOT_DIR' ) ) {
+	define( 'YOAST_DUPLICATE_POST_TEST_ROOT_DIR', __DIR__ . '/' ); // Includes trailing slash.
+}
+
+/*
+ * Load the plugin(s).
+ */
+require_once dirname( dirname( __DIR__ ) ) . '/vendor/yoast/wp-test-utils/src/WPIntegration/bootstrap-functions.php';
+
+$GLOBALS['wp_tests_options'] = [
+	'active_plugins' => [
+		'duplicate-post/duplicate-post',
+	],
+];
+
+$_wp_tests_dir = WPIntegration\get_path_to_wp_test_dir();
+if ( $_wp_tests_dir === false ) {
+	$_wp_tests_dir = YOAST_DUPLICATE_POST_TEST_ROOT_DIR . '../../../../tests/phpunit/';
+}
+
+
+// Load some helpful functions.
+require_once $_wp_tests_dir . 'includes/functions.php';
+
+/**
+ * Activates this plugin in WordPress so it can be tested.
+ */
+function _manually_load_plugin() {
+	require YOAST_DUPLICATE_POST_TEST_ROOT_DIR . '../../duplicate-post.php';
+}
+
+tests_add_filter( 'muplugins_loaded', '_manually_load_plugin' );
+
+/*
+ * Load WordPress, which will load the Composer autoload file, and load the MockObject autoloader after that.
+ */
+WPIntegration\bootstrap_it();

tests/integration/post-duplicator-test.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace Yoast\WP\Duplicate_Post\Tests\Integration;
+
+/**
+ * Yoast Duplicate Post plugin test file.
+ *
+ * @package Yoast\WP\Duplicate_Post\Tests
+ */
+
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+use Yoast\WP\Duplicate_Post\Post_Duplicator;
+
+/**
+ * Class Post_Duplicator.
+ *
+ * @coversDefaultClass \Yoast\WP\Duplicate_Post\Post_Duplicator
+ */
+class Post_Duplicator_Test extends TestCase {
+
+	/**
+	 * Instance of the Post_Duplicator class.
+	 *
+	 * @var Post_Duplicator
+	 */
+	private $instance;
+
+	/**
+	 * Setting up the instance of Post_Duplicator.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		$this->instance = new Post_Duplicator();
+	}
+
+	/**
+	 * Tests whether the admin page is generated correctly.
+	 *
+	 * @covers ::create_duplicate
+	 * @covers ::get_default_options
+	 * @covers ::generate_copy_title
+	 * @covers ::generate_copy_status
+	 * @covers ::generate_copy_author
+	 */
+	public function test_create_duplicate() {
+
+		$post = $this->factory->post->create_and_get();
+
+		$id = $this->instance->create_duplicate( $post );
+
+		$this->assertTrue( \is_int( $id ) );
+	}
+}