Use a custom version of PHPUnit 7 for PHP 8 compatibility

This commit replaces the standard PHPUnit 7 package with a custom
GitHub fork with modifications to support PHP 8.

composer.json

@@ -19,10 +19,16 @@
     "woocommerce/woocommerce-blocks": "3.4.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "7.5.20",
+    "phpunit/phpunit": "dev-add-compatibility-with-php8-to-phpunit-7",
     "woocommerce/woocommerce-sniffs": "0.1.0",
     "wp-cli/i18n-command": "2.2.5"
   },
+  "repositories": [
+    {
+      "type": "vcs",
+      "url": "https://github.com/woocommerce/phpunit"
+    }
+  ],
   "config": {
     "platform": {
       "php": "7.1"

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "dcf828ebdcdcecfa605e7d3516f6e769",
+    "content-hash": "4c864b8074b4d5dc351694560349f17f",
     "packages": [
         {
             "name": "automattic/jetpack-autoloader",
@@ -682,6 +682,20 @@
                 "constructor",
                 "instantiate"
             ],
+            "funding": [
+                {
+                    "url": "https://www.doctrine-project.org/sponsorship.html",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://www.patreon.com/phpdoctrine",
+                    "type": "patreon"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/doctrine%2Finstantiator",
+                    "type": "tidelift"
+                }
+            ],
             "time": "2020-05-29T17:27:14+00:00"
         },
         {
@@ -944,6 +958,12 @@
                 "object",
                 "object graph"
             ],
+            "funding": [
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/myclabs/deep-copy",
+                    "type": "tidelift"
+                }
+            ],
             "time": "2020-06-29T13:22:24+00:00"
         },
         {
@@ -1674,16 +1694,16 @@
         },
         {
             "name": "phpunit/phpunit",
-            "version": "7.5.20",
+            "version": "dev-add-compatibility-with-php8-to-phpunit-7",
             "source": {
                 "type": "git",
-                "url": "https://github.com/sebastianbergmann/phpunit.git",
+                "url": "https://github.com/woocommerce/phpunit.git",
-                "reference": "9467db479d1b0487c99733bb1e7944d32deded2c"
+                "reference": "6f4610e48d08489645bd2b5570f9b5e399c9d6db"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/9467db479d1b0487c99733bb1e7944d32deded2c",
+                "url": "https://api.github.com/repos/woocommerce/phpunit/zipball/6f4610e48d08489645bd2b5570f9b5e399c9d6db",
-                "reference": "9467db479d1b0487c99733bb1e7944d32deded2c",
+                "reference": "6f4610e48d08489645bd2b5570f9b5e399c9d6db",
                 "shasum": ""
             },
             "require": {
@@ -1736,7 +1756,17 @@
                     "src/"
                 ]
             },
-            "notification-url": "https://packagist.org/downloads/",
+            "autoload-dev": {
+                "classmap": [
+                    "tests/"
+                ],
+                "files": [
+                    "src/Framework/Assert/Functions.php",
+                    "tests/_files/CoverageNamespacedFunctionTest.php",
+                    "tests/_files/CoveredFunction.php",
+                    "tests/_files/NamespaceCoveredFunction.php"
+                ]
+            },
             "license": [
                 "BSD-3-Clause"
             ],
@@ -1754,7 +1784,21 @@
                 "testing",
                 "xunit"
             ],
-            "time": "2020-01-08T08:45:45+00:00"
+            "support": {
+                "issues": "https://github.com/sebastianbergmann/phpunit/issues",
+                "source": "https://github.com/woocommerce/phpunit/tree/add-compatibility-with-php8-to-phpunit-7"
+            },
+            "funding": [
+                {
+                    "type": "github",
+                    "url": "https://github.com/sebastianbergmann"
+                },
+                {
+                    "type": "custom",
+                    "url": "https://phpunit.de/donate.html"
+                }
+            ],
+            "time": "2020-10-02T10:22:34+00:00"
         },
         {
             "name": "rmccue/requests",
@@ -2531,6 +2575,20 @@
                 "polyfill",
                 "portable"
             ],
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
             "time": "2020-07-14T12:35:20+00:00"
         },
         {
@@ -2928,7 +2986,9 @@
     ],
     "aliases": [],
     "minimum-stability": "dev",
-    "stability-flags": [],
+    "stability-flags": {
+        "phpunit/phpunit": 20
+    },
     "prefer-stable": true,
     "prefer-lowest": false,
     "platform": {
@@ -2937,5 +2997,6 @@
     "platform-dev": [],
     "platform-overrides": {
         "php": "7.1"
-    }
+    },
+    "plugin-api-version": "1.1.0"
 }