Composer is a tool for dependency management in PHP. It allows you to declare the libraries your project depends on and it will manage (install/update) them for you.

Composer is not a package manager in the same sense as Yum or Apt are. Yes, it deals with "packages" or libraries, but it manages them on a per-project basis, installing them in a directory (e.g. vendor) inside your project. By default it will never install anything globally.

Moreover, Composer supports autoloading of classes, which means that you can use classes without even including the files that define them.

Composer offers a convenient installer that you can execute directly from the command line. Feel free to download this file or review it on GitHub if you wish to know more about the inner workings of the installer.

To install composer, run the following command in your terminal:

php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"

php -r "if (hash_file('sha384', 'composer-setup.php') === 'e0012edf3e80b6978849f5eff0d4b4e4c79ff1609dd1e613307e16318854d24ae64f26d17af3ef0bf7cfb710ca74755a') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"

php composer-setup.php

php -r "unlink('composer-setup.php');"

This installer script will simply check some php.ini settings, warn you if they are set incorrectly, and then download the latest composer.phar in the current directory. The 4 lines above will, in order:

1. Download the installer to the current directory
2. Verify the installer SHA-384 which you can also cross-check here
3. Run the installer
4. Remove the installer

You can install Composer to a specific directory by using the --install-dir option and providing a target directory.

php composer-setup.php --install-dir=bin

Alternatively, you can install Composer globally.

php composer-setup.php --install-dir=bin --filename=composer

Note: If the above fails due to permissions, you may need to run it again with sudo.

Note: Composer requires PHP 5.3.2+ to run. A few sensitive php settings and compile flags are also required, but when using the installer you will be warned about any incompatibilities.

Note: If you are running OS X, you can also install Composer by following the instructions here.

Note: If you are on Windows and have XAMPP installed, you may need to use the php command instead of php when following the command-line installation instructions above.

Note: If the above fails, you can manually download the installer here and run the same commands without the first line.

Note: Composer will just check a few PHP settings and then download composer.phar to your working directory. This file is the Composer binary. It is a PHAR (PHP archive), which is an archive format for PHP which can be run on the command line, amongst other things.

Note: You can place the Composer PHAR anywhere you wish. If you put it in a directory that is part of your PATH, you can access it globally. On unixy systems you can even make it executable and invoke it without directly using the php interpreter.

Note: If you want to run Composer from anywhere on your system, you can create a global composer command (on Unix systems) with the following commands:

curl -sS https://getcomposer.org/installer | php

sudo mv composer.phar /usr/local/bin/composer

Note: If the above fails due to permissions, you may need to run it again with sudo.

Note: If you prefer a graphical user interface (GUI) instead of the command line, you can try Composer GUI.

Note: If you want to install Composer to be used by all users on your system, you may place it in /usr/local/bin.

Note: If you are using SELinux, make sure you have set the httpd_execmem permission to allow PHP to execute external programs, otherwise you will get a cryptic error message like Failed to execute the Phar or phar error: exec failed.

Note: If you are using cPanel, you will need to use the command line method listed above.

PHPUnit is a programmer-oriented testing framework for PHP. It is an instance of the xUnit architecture for unit testing frameworks.

PHPUnit is the de-facto standard for unit testing in PHP projects. It provides both a framework that makes the writing of tests easy as well as the functionality to easily run the tests and analyse their results.

PHPUnit is distributed through PHAR and available on Packagist. It can be installed globally in seconds and is then available to check your application.

PHPUnit 9.0 supports PHP 7.3, PHP 7.4, and PHP 8.0.

PHPUnit 8.5 supports PHP 7.2, PHP 7.3, and PHP 7.4.

PHPUnit 7.5 supports PHP 7.1, PHP 7.2, and PHP 7.3.

PHPUnit 6.5 supports PHP 7.0, PHP 7.1, and PHP 7.2.

PHPUnit 5.7 supports PHP 5.6, PHP 7.0, and PHP 7.1.

The recommended way to install PHPUnit is via Composer.

composer require --dev phpunit/phpunit

Composer will install the proper PHPUnit version in the vendor/bin directory.

To verify that PHPUnit has been installed correctly, run the phpunit --version command.