Composerを使用してCakePHP2.6のdebug kitやphpunitインストール時のエラー[Your requirements could not be resolved to an installable set of packages.]

CakePHP2.6にあったcomposer.jsonからのdebug kitやphpunitを、composerからインストールしようとして以下のコマンド実行でエラーとなりました。

# composer install

Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

 Problem 1
 - The requested PHP extension ext-mcrypt * is missing from your system. Install or enable PHP's mcrypt extension.
 Problem 2
 - phpunit/phpunit 3.7.9 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.8 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.7 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.6 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.5 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.4 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.38 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.37 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.36 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.35 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.34 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.33 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.32 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.31 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.30 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.3 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.29 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.28 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.27 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.26 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.25 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.24 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.23 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.22 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.21 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.20 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.2 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.19 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.18 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.17 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.16 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.15 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.14 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.13 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.12 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.11 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.10 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.1 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - phpunit/phpunit 3.7.0 requires ext-dom * -> the requested PHP extension dom is missing from your system.
 - Installation request for phpunit/phpunit 3.7.* -> satisfiable by phpunit/phpunit[3.7.0, 3.7.1, 3.7.10, 3.7.11, 3.7.12, 3.7.13, 3.7.14, 3.7.15, 3.7.16, 3.7.17, 3.7.18, 3.7.19, 3.7.2, 3.7.20, 3.7.21, 3.7.22, 3.7.23, 3.7.24, 3.7.25, 3.7.26, 3.7.27, 3.7.28, 3.7.29, 3.7.3, 3.7.30, 3.7.31, 3.7.32, 3.7.33, 3.7.34, 3.7.35, 3.7.36, 3.7.37, 3.7.38, 3.7.4, 3.7.5, 3.7.6, 3.7.7, 3.7.8, 3.7.9].

 To enable extensions, verify that they are enabled in those .ini files:
 - /etc/php.ini
 - /etc/php.d/20-bz2.ini
 - /etc/php.d/20-calendar.ini
 - /etc/php.d/20-ctype.ini
 - /etc/php.d/20-curl.ini
 - /etc/php.d/20-exif.ini
 - /etc/php.d/20-fileinfo.ini
 - /etc/php.d/20-ftp.ini
 - /etc/php.d/20-gd.ini
 - /etc/php.d/20-gettext.ini
 - /etc/php.d/20-iconv.ini
 - /etc/php.d/20-mbstring.ini
 - /etc/php.d/20-mysqlnd.ini
 - /etc/php.d/20-pdo.ini
 - /etc/php.d/20-phar.ini
 - /etc/php.d/20-sockets.ini
 - /etc/php.d/20-sqlite3.ini
 - /etc/php.d/20-tokenizer.ini
 - /etc/php.d/30-mysql.ini
 - /etc/php.d/30-mysqli.ini
 - /etc/php.d/30-pdo_mysql.ini
 - /etc/php.d/30-pdo_sqlite.ini
 - /etc/php.d/40-json.ini
 - /etc/php.d/40-zip.ini
 You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

問題が２つあるようです。

何かやろうとするたびにエラーが出ますが、１つずつ記録を取りながら進めたいと思います。

１．PHP extension ext-mcrypt　がない

※結構はまりました。以下記事参照。

https://normalblog.net/system/composer/php-extension-ext-mcrypt/

２．PHP extension dom　がない

以下記事にて対応。

https://normalblog.net/system/composer/composer-error-the-requested-php-extension-dom-is-missing-from-your-system/

再実行

上記の問題２点を解消し、再びインストール！

# composer install

↓

[root@localhost]# composer install
Loading composer repositories with package information
Updating dependencies (including require-dev)
 - Installing composer/installers (v1.0.24)
 Downloading: 100%

 - Installing symfony/yaml (v2.8.4)
 Downloading: 100%

 - Installing phpunit/php-text-template (1.2.1)
 Downloading: 100%

 - Installing phpunit/phpunit-mock-objects (1.2.3)
 Downloading: 100%

 - Installing phpunit/php-timer (1.0.7)
 Downloading: 100%

 - Installing phpunit/php-token-stream (1.2.2)
 Downloading: 100%

 - Installing phpunit/php-file-iterator (1.4.1)
 Downloading: 100%

 - Installing phpunit/php-code-coverage (1.2.18)
 Downloading: 100%

 - Installing phpunit/phpunit (3.7.38)
 Downloading: 100%

 - Installing cakephp/debug_kit (2.2.6)
 Downloading: 100%

phpunit/phpunit-mock-objects suggests installing ext-soap (*)
phpunit/php-code-coverage suggests installing ext-xdebug (>=2.0.5)
phpunit/phpunit suggests installing phpunit/php-invoker (~1.1)
Writing lock file
Generating autoload files

出来ました。本当に良かったです・・・

こういう思いもよらなかったエラーによる環境設定が結構時間かかりますね。