Remove WP_Mock from the tests

- composer remove --dev 10up/wp_mock
- composer require --dev php-mock/php-mock-mockery
- Manually replaced WP_Mock with PHPMockery

WP_Mock has dependencies on older versions of packages. This ends up
conflicting with the newer versions of more actively-developed packages.
Removing this dependency allows us greater flexibility in the packages
we install.

wp-content/themes/theme/app/Theme/Plugins.php

@@ -13,6 +13,10 @@ public function __construct(array $required = [])
     {
         $this->required = $required;
         $this->path_to_wordpress = ABSPATH;
+        // For the tests
+        $this->requireOnce = function ($a) {
+            require_once($a);
+        };
     }
 
     public function register()
@@ -27,7 +31,7 @@ public function checkDependencies()
             return;
         }
         if (!function_exists('get_plugin_data')) {
-            require_once($this->path_to_wordpress . 'wp-admin/includes/plugin.php');
+            call_user_func($this->requireOnce, $this->path_to_wordpress . 'wp-admin/includes/plugin.php');
         }
         array_map([$this, 'addNotice'], $pluginsToActivate);
     }

wp-content/themes/theme/composer.json

@@ -18,12 +18,12 @@
     },
     "require-dev": {
         "dxw/phar-install": "^1.0",
-        "10up/wp_mock": "^0.3.0",
         "mikey179/vfsstream": "^1.6",
         "peridot-php/peridot": "^1.19",
         "peridot-php/leo": "^1.6",
         "peridot-php/peridot-dot-reporter": "^1.0",
-        "dxw/php-cs-fixer-config": "^1.0"
+        "dxw/php-cs-fixer-config": "^1.0",
+        "php-mock/php-mock-mockery": "^1.3"
     },
     "autoload": {
         "psr-4": {