diff --git a/.gitignore b/.gitignore
index 6101c86..7bb709d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,4 @@ node_modules/
 *.tar.gz
 *.zip
 vendor/
+.phpunit.result.cache
diff --git a/README.md b/README.md
index 340fc9e..c6ead29 100644
--- a/README.md
+++ b/README.md
@@ -10,3 +10,24 @@ define( 'GEOLONIA_GIS_DEFAULT_ZOOM', 16 );
 define( 'GEOLONIA_GIS_DEFAULT_LAT', 34.86707002642607 );
 define( 'GEOLONIA_GIS_DEFAULT_LNG', 138.32283481501884 );
 ```
+
+
+## 開発者向け
+
+### テスト環境のセットアップ
+
+- 初回のみ以下のコマンドを実行して依存関係のインストールと、テスト用の WordPress のセットアップを行ってください。
+- `svn` と `php` のインストールが必要です
+
+```bash
+$ composer install
+$ bash bin/install-wp-tests.sh wordpress_test root '' localhost latest
+```
+
+### テストの実行
+
+テストを実行するためには、以下のコマンドを実行してください。
+
+```bash
+$ composer test
+```
diff --git a/composer.json b/composer.json
index e597722..51d1c82 100644
--- a/composer.json
+++ b/composer.json
@@ -3,5 +3,8 @@
     "phpunit/phpunit": "^8.0",
     "yoast/phpunit-polyfills": "^2.0",
     "doctrine/instantiator": "^1.4"
+  },
+  "scripts": {
+    "test": "phpunit"
   }
 }
diff --git a/geolonia-open-gis.php b/geolonia-open-gis.php
index 14a80a4..ede9661 100644
--- a/geolonia-open-gis.php
+++ b/geolonia-open-gis.php
@@ -42,13 +42,10 @@
 
 require_once( dirname( __FILE__) . '/inc/functions.php' );
 
-add_action( 'plugins_loaded', function() {
-	load_plugin_textdomain(
-		"geolonia-open-gis",
-		false,
-		dirname( plugin_basename( __FILE__ ) ).'/languages'
-	 );
-} );
+function geolonia_gis_load_textdomain() {
+	return load_plugin_textdomain( 'geolonia-open-gis', false, dirname( plugin_basename( __FILE__ ) ) . '/languages' );
+}
+add_action( 'plugins_loaded', 'geolonia_gis_load_textdomain');
 
 // Registers the custom post type `maps`.
 add_action( 'init', function() {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 50421ec..e8e8560 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -10,7 +10,6 @@
 	<testsuites>
 		<testsuite name="testing">
 			<directory prefix="test-" suffix=".php">./tests/</directory>
-			<exclude>./tests/test-sample.php</exclude>
 		</testsuite>
 	</testsuites>
 </phpunit>
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 78a7b42..1d38831 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -5,6 +5,10 @@
  * @package Geolonia_Gis
  */
 
+
+// WP_PLUGIN_DIR　現在のプラグインの上位ディレクトリを指定する
+define('WP_PLUGIN_DIR', dirname(dirname(dirname(__FILE__))));
+
 // Load PHPUnit Polyfills.
 require_once dirname( __FILE__ ) . '/../vendor/yoast/phpunit-polyfills/phpunitpolyfills-autoload.php';
 
diff --git a/tests/test-load-textdomain.php b/tests/test-load-textdomain.php
new file mode 100644
index 0000000..d2f524a
--- /dev/null
+++ b/tests/test-load-textdomain.php
@@ -0,0 +1,73 @@
+<?php
+/**
+ * Class TestLoadTextdomain
+ */
+
+class Test_LoadTextdomain extends WP_UnitTestCase {
+	protected static $user_id;
+
+	public static function wpSetUpBeforeClass( WP_UnitTest_Factory $factory ) {
+		self::$user_id = $factory->user->create(
+			array(
+				'role'   => 'administrator',
+				'locale' => 'ja',
+			)
+		);
+	}
+
+	/**
+	 * @covers ::geolonia_gis_load_textdomain
+	 */
+	public function test_load_textdomain() {
+
+		add_filter('locale', function() {
+			return 'ja';
+		});
+		$this->assertTrue( geolonia_gis_load_textdomain() );
+	}
+
+	/**
+	 * @covers ::geolonia_gis_load_textdomain
+	 */
+	public function test_load_textdomain_by_plugin_locale() {
+		add_filter('plugin_locale', function() {
+			return 'ja';
+		});
+		$this->assertTrue( geolonia_gis_load_textdomain() );
+	}
+
+	/**
+	 * @covers ::geolonia_gis_load_textdomain
+	 */
+	public function test_load_textdomain_when_locale_is_english() {
+		add_filter('locale', function() {
+			return 'en_US';
+		});
+		$this->assertFalse( geolonia_gis_load_textdomain() );
+	}
+
+	/**
+	 * @covers ::geolonia_gis_load_textdomain
+	 */
+	public function test_load_textdomain_plugin_locale_is_english() {
+		add_filter('plugin_locale', function() {
+			return 'en_US';
+		});
+		$this->assertFalse( geolonia_gis_load_textdomain() );
+	}
+
+	/**
+	 * @covers ::geolonia_gis_load_textdomain
+	 */
+	public function test_load_textdomain_user_locale_is_japanese() {
+
+		add_filter('locale', function() {
+			return 'en_US';
+		});
+
+		set_current_screen( 'dashboard' );
+		wp_set_current_user( self::$user_id );
+
+		$this->assertTrue( geolonia_gis_load_textdomain() );
+	}
+}
diff --git a/tests/test-register_post_type_maps.php b/tests/test-register_post_type_maps.php
new file mode 100644
index 0000000..d24fde9
--- /dev/null
+++ b/tests/test-register_post_type_maps.php
@@ -0,0 +1,94 @@
+<?php
+
+class Test_Register_Post_Type_Maps extends WP_UnitTestCase {
+
+	public function set_up() {
+		parent::set_up();
+
+		unregister_post_type( 'maps' );
+	}
+
+	/**
+	 * @covers ::register_post_type_maps
+	 */
+	public function test_maps_post_type_registered() {
+
+		$this->assertNull( get_post_type_object( 'maps' ) );
+
+		register_post_type_maps();
+
+		$maps_object = get_post_type_object( 'maps' );
+
+        $this->assertInstanceOf( 'WP_Post_Type', $maps_object );
+		$this->assertSame( 'maps', $maps_object->name );
+	}
+
+    /**
+     * @covers ::register_post_type_maps
+     */
+    public function test_maps_post_type_options() {
+
+        $this->assertNull( get_post_type_object( 'maps' ) );
+
+        register_post_type_maps();
+
+        $maps_object = get_post_type_object( 'maps' );
+
+        // labels の設定値を確認
+        $this->assertSame( 'Map', $maps_object->label );
+
+        // public の設定値を確認
+        $this->assertTrue( $maps_object->public );
+
+        // hierarchical の設定値を確認
+        $this->assertFalse( $maps_object->hierarchical );
+
+        // show_ui の設定値を確認
+        $this->assertTrue( $maps_object->show_ui );
+
+        // show_in_menu の設定値を確認
+        $this->assertTrue( $maps_object->show_in_nav_menus );
+
+		// カスタム投稿タイプの supports に title が含まれているか確認
+		$this->assertTrue( post_type_supports( 'maps', 'title' ), 'Title support is enabled' );
+
+		// カスタム投稿タイプの supports に editor が含まれているか確認
+		$this->assertTrue( post_type_supports( 'maps', 'editor' ), 'Editor support is enabled' );
+
+		// カスタム投稿タイプの supports に author が含まれているか確認
+		$this->assertTrue( post_type_supports( 'maps', 'revisions' ), 'Revisions support is enabled' );
+
+		// カスタム投稿タイプの supports に excerpt が含まれているか確認
+		$this->assertTrue( post_type_supports( 'maps', 'excerpt' ), 'Excerpt support is enabled' );
+
+        // archive の設定値を確認
+        $this->assertFalse( $maps_object->has_archive );
+
+        // rewrite の設定値を確認
+        $this->assertSame( array('slug' => 'maps'), $maps_object->rewrite );
+
+        // query_var の設定値を確認
+        $this->assertSame( 'maps', $maps_object->query_var );
+
+        // menu_icon の設定値を確認
+        $this->assertSame( 'dashicons-location', $maps_object->menu_icon );
+
+        // show_in_rest の設定値を確認
+        $this->assertTrue( $maps_object->show_in_rest );
+
+        // rest_base の設定値を確認
+        $this->assertSame( GEOLONIA_GIS_POST_TYPE, $maps_object->rest_base );
+
+		// rest_controller_class の設定値を確認
+        $this->assertSame( 'WP_REST_Posts_Controller', $maps_object->rest_controller_class );
+
+        // taxonomies の設定値を確認
+        $this->assertSame( array( 'map_tag' ), $maps_object->taxonomies );
+
+        // capability_type の設定値を確認
+        $this->assertSame( 'map', $maps_object->capability_type );
+
+        // map_meta_cap の設定値を確認
+        $this->assertTrue( $maps_object->map_meta_cap );
+    }
+}
diff --git a/tests/test-sample.php b/tests/test-sample.php
deleted file mode 100644
index 3fd328b..0000000
--- a/tests/test-sample.php
+++ /dev/null
@@ -1,20 +0,0 @@
-<?php
-/**
- * Class SampleTest
- *
- * @package Geolonia_Gis
- */
-
-/**
- * Sample test case.
- */
-class SampleTest extends WP_UnitTestCase {
-
-	/**
-	 * A single example test.
-	 */
-	public function test_sample() {
-		// Replace this with some actual testing code.
-		$this->assertTrue( true );
-	}
-}