Create Force_Single_Plugin_Preparation

[jjgrainger]

Description

Create a new Force_Single_Plugin_Preparation that will force the plugin to be checks as the only active plugin.

Acceptance Criteria

• Class Force_Single_Plugin_Preparation should be created and exists at includes/Checker/Preparations
• Class Force_Single_Plugin_Preparation should extend Preparation interface
• Class should have a protected property $plugin_basename
• Class constructor accepts a single string $plugin_basename parameter
• Class contains a prepare() method that does the following
  • Check the plugin folder exists in the plugins directory using the $plugin_basename property
  • If the plugin does not exist, and exception is thrown
  • Ensures the plugin and the plugin check plugin are the only in the active list of plugins using the following filters:
    • option_active_plugins
    • default_option_active_plugins
  • Returns a cleanup function that removes the filters added
• Class contains a public filter_active_plugins() method that accepts an $active_plugins parameter
  • The method checks if the $this->plugin_basename exists in the array, and if it does, ensures the $plugin_basename and plugin checker plugin name are only in the active plugins array.

Test Coverage

• Test the prepare method throws and exception if the plugin does not exist in the filesystem.
• Test the prepare method prepares the environment by ensuring that the get_option( 'active_plugins' ) array includes the $plugin_basename.
• Test the filter_active_plugins returns the $plugin_basename property and plugin checker basename in the array passed when it exist.
• Test the prepare method returns a callable cleanup function.

[jjgrainger]

@felixarntz new issue and AC's added for the Force_Single_Plugin_Preparation

[felixarntz]

@jjgrainger ACs look good, just one critical thing needs to be updated/clarified: The filter for the active plugins option should not append the plugin - we had decided to only do runtime checks when the plugin is active, so if that isn't already the case, we must not force it. The purpose of this preparation is instead to ensure only that plugin is active.

Essentially, if the plugin to check is in the list of the active plugins, ensure that only that plugin and the plugin check plugin itself remain in the list of active plugins after the filter.

[jjgrainger]

Thanks @felixarntz I've updated based on your comments.