diff --git a/composer.json b/composer.json
index cac758e28a9a702d1cb9169dca9b35838cdc5627..8612c77ac221ba3933816e0dd51a33e362a52b0d 100644
--- a/composer.json
+++ b/composer.json
@@ -52,8 +52,6 @@
         "post-autoload-dump": "Drupal\\Core\\Composer\\Composer::ensureHtaccess",
         "post-package-install": "Drupal\\Core\\Composer\\Composer::vendorTestCodeCleanup",
         "post-package-update": "Drupal\\Core\\Composer\\Composer::vendorTestCodeCleanup",
-        "drupal-phpunit-upgrade-check": "Drupal\\Core\\Composer\\Composer::upgradePHPUnit",
-        "drupal-phpunit-upgrade": "@composer update phpunit/phpunit phpspec/prophecy symfony/yaml --with-dependencies --no-progress",
         "phpcs": "phpcs --standard=core/phpcs.xml.dist --runtime-set installed_paths $($COMPOSER_BINARY config vendor-dir)/drupal/coder/coder_sniffer --",
         "phpcbf": "phpcbf --standard=core/phpcs.xml.dist --runtime-set installed_paths $($COMPOSER_BINARY config vendor-dir)/drupal/coder/coder_sniffer --"
     },
diff --git a/composer.lock b/composer.lock
index a934df60e44bfb6caabe054af5f14aba61116b4d..05ca71eec56419f65dcefff763734be63be9c0e4 100644
--- a/composer.lock
+++ b/composer.lock
@@ -3800,6 +3800,153 @@
             "homepage": "http://vfs.bovigo.org/",
             "time": "2017-08-01T08:02:14+00:00"
         },
+        {
+            "name": "myclabs/deep-copy",
+            "version": "1.7.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/myclabs/DeepCopy.git",
+                "reference": "3b8a3a99ba1f6a3952ac2747d989303cbd6b7a3e"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/myclabs/DeepCopy/zipball/3b8a3a99ba1f6a3952ac2747d989303cbd6b7a3e",
+                "reference": "3b8a3a99ba1f6a3952ac2747d989303cbd6b7a3e",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.6 || ^7.0"
+            },
+            "require-dev": {
+                "doctrine/collections": "^1.0",
+                "doctrine/common": "^2.6",
+                "phpunit/phpunit": "^4.1"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "DeepCopy\\": "src/DeepCopy/"
+                },
+                "files": [
+                    "src/DeepCopy/deep_copy.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "Create deep copies (clones) of your objects",
+            "keywords": [
+                "clone",
+                "copy",
+                "duplicate",
+                "object",
+                "object graph"
+            ],
+            "time": "2017-10-19T19:58:43+00:00"
+        },
+        {
+            "name": "phar-io/manifest",
+            "version": "1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phar-io/manifest.git",
+                "reference": "2df402786ab5368a0169091f61a7c1e0eb6852d0"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phar-io/manifest/zipball/2df402786ab5368a0169091f61a7c1e0eb6852d0",
+                "reference": "2df402786ab5368a0169091f61a7c1e0eb6852d0",
+                "shasum": ""
+            },
+            "require": {
+                "ext-dom": "*",
+                "ext-phar": "*",
+                "phar-io/version": "^1.0.1",
+                "php": "^5.6 || ^7.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Arne Blankerts",
+                    "email": "arne@blankerts.de",
+                    "role": "Developer"
+                },
+                {
+                    "name": "Sebastian Heuer",
+                    "email": "sebastian@phpeople.de",
+                    "role": "Developer"
+                },
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de",
+                    "role": "Developer"
+                }
+            ],
+            "description": "Component for reading phar.io manifest information from a PHP Archive (PHAR)",
+            "time": "2017-03-05T18:14:27+00:00"
+        },
+        {
+            "name": "phar-io/version",
+            "version": "1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phar-io/version.git",
+                "reference": "a70c0ced4be299a63d32fa96d9281d03e94041df"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phar-io/version/zipball/a70c0ced4be299a63d32fa96d9281d03e94041df",
+                "reference": "a70c0ced4be299a63d32fa96d9281d03e94041df",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.6 || ^7.0"
+            },
+            "type": "library",
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Arne Blankerts",
+                    "email": "arne@blankerts.de",
+                    "role": "Developer"
+                },
+                {
+                    "name": "Sebastian Heuer",
+                    "email": "sebastian@phpeople.de",
+                    "role": "Developer"
+                },
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de",
+                    "role": "Developer"
+                }
+            ],
+            "description": "Library for handling version information and constraints",
+            "time": "2017-03-05T17:38:23+00:00"
+        },
         {
             "name": "phpdocumentor/reflection-docblock",
             "version": "2.0.4",
@@ -3914,39 +4061,40 @@
         },
         {
             "name": "phpunit/php-code-coverage",
-            "version": "2.2.4",
+            "version": "5.3.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/php-code-coverage.git",
-                "reference": "eabf68b476ac7d0f73793aada060f1c1a9bf8979"
+                "reference": "c89677919c5dd6d3b3852f230a663118762218ac"
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-                "url": "https://api.github.com/repos/sebastianbergmann/php-code-coverage/zipball/eabf68b476ac7d0f73793aada060f1c1a9bf8979",
-                "reference": "eabf68b476ac7d0f73793aada060f1c1a9bf8979",
+                "url": "https://api.github.com/repos/sebastianbergmann/php-code-coverage/zipball/c89677919c5dd6d3b3852f230a663118762218ac",
+                "reference": "c89677919c5dd6d3b3852f230a663118762218ac",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.3",
-                "phpunit/php-file-iterator": "~1.3",
-                "phpunit/php-text-template": "~1.2",
-                "phpunit/php-token-stream": "~1.3",
-                "sebastian/environment": "^1.3.2",
-                "sebastian/version": "~1.0"
+                "ext-dom": "*",
+                "ext-xmlwriter": "*",
+                "php": "^7.0",
+                "phpunit/php-file-iterator": "^1.4.2",
+                "phpunit/php-text-template": "^1.2.1",
+                "phpunit/php-token-stream": "^2.0.1",
+                "sebastian/code-unit-reverse-lookup": "^1.0.1",
+                "sebastian/environment": "^3.0",
+                "sebastian/version": "^2.0.1",
+                "theseer/tokenizer": "^1.1"
             },
             "require-dev": {
-                "ext-xdebug": ">=2.1.4",
-                "phpunit/phpunit": "~4"
+                "phpunit/phpunit": "^6.0"
             },
             "suggest": {
-                "ext-dom": "*",
-                "ext-xdebug": ">=2.2.1",
-                "ext-xmlwriter": "*"
+                "ext-xdebug": "^2.5.5"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.2.x-dev"
+                    "dev-master": "5.3.x-dev"
                 }
             },
             "autoload": {
@@ -3961,7 +4109,7 @@
             "authors": [
                 {
                     "name": "Sebastian Bergmann",
-                    "email": "sb@sebastian-bergmann.de",
+                    "email": "sebastian@phpunit.de",
                     "role": "lead"
                 }
             ],
@@ -3972,7 +4120,7 @@
                 "testing",
                 "xunit"
             ],
-            "time": "2015-10-06T15:47:00+00:00"
+            "time": "2018-04-06T15:36:58+00:00"
         },
         {
             "name": "phpunit/php-file-iterator",
@@ -4113,29 +4261,29 @@
         },
         {
             "name": "phpunit/php-token-stream",
-            "version": "1.4.12",
+            "version": "2.0.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/php-token-stream.git",
-                "reference": "1ce90ba27c42e4e44e6d8458241466380b51fa16"
+                "reference": "791198a2c6254db10131eecfe8c06670700904db"
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             "dist": {
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-                "reference": "1ce90ba27c42e4e44e6d8458241466380b51fa16",
+                "url": "https://api.github.com/repos/sebastianbergmann/php-token-stream/zipball/791198a2c6254db10131eecfe8c06670700904db",
+                "reference": "791198a2c6254db10131eecfe8c06670700904db",
                 "shasum": ""
             },
             "require": {
                 "ext-tokenizer": "*",
-                "php": ">=5.3.3"
+                "php": "^7.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.2"
+                "phpunit/phpunit": "^6.2.4"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.4-dev"
+                    "dev-master": "2.0-dev"
                 }
             },
             "autoload": {
@@ -4158,45 +4306,57 @@
             "keywords": [
                 "tokenizer"
             ],
-            "time": "2017-12-04T08:55:13+00:00"
+            "time": "2017-11-27T05:48:46+00:00"
         },
         {
             "name": "phpunit/phpunit",
-            "version": "4.8.36",
+            "version": "6.5.14",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "46023de9a91eec7dfb06cc56cb4e260017298517"
+                "reference": "bac23fe7ff13dbdb461481f706f0e9fe746334b7"
             },
             "dist": {
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-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/46023de9a91eec7dfb06cc56cb4e260017298517",
-                "reference": "46023de9a91eec7dfb06cc56cb4e260017298517",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/bac23fe7ff13dbdb461481f706f0e9fe746334b7",
+                "reference": "bac23fe7ff13dbdb461481f706f0e9fe746334b7",
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             },
             "require": {
                 "ext-dom": "*",
                 "ext-json": "*",
-                "ext-pcre": "*",
-                "ext-reflection": "*",
-                "ext-spl": "*",
-                "php": ">=5.3.3",
-                "phpspec/prophecy": "^1.3.1",
-                "phpunit/php-code-coverage": "~2.1",
-                "phpunit/php-file-iterator": "~1.4",
-                "phpunit/php-text-template": "~1.2",
-                "phpunit/php-timer": "^1.0.6",
-                "phpunit/phpunit-mock-objects": "~2.3",
-                "sebastian/comparator": "~1.2.2",
-                "sebastian/diff": "~1.2",
-                "sebastian/environment": "~1.3",
-                "sebastian/exporter": "~1.2",
-                "sebastian/global-state": "~1.0",
-                "sebastian/version": "~1.0",
-                "symfony/yaml": "~2.1|~3.0"
+                "ext-libxml": "*",
+                "ext-mbstring": "*",
+                "ext-xml": "*",
+                "myclabs/deep-copy": "^1.6.1",
+                "phar-io/manifest": "^1.0.1",
+                "phar-io/version": "^1.0",
+                "php": "^7.0",
+                "phpspec/prophecy": "^1.7",
+                "phpunit/php-code-coverage": "^5.3",
+                "phpunit/php-file-iterator": "^1.4.3",
+                "phpunit/php-text-template": "^1.2.1",
+                "phpunit/php-timer": "^1.0.9",
+                "phpunit/phpunit-mock-objects": "^5.0.9",
+                "sebastian/comparator": "^2.1",
+                "sebastian/diff": "^2.0",
+                "sebastian/environment": "^3.1",
+                "sebastian/exporter": "^3.1",
+                "sebastian/global-state": "^2.0",
+                "sebastian/object-enumerator": "^3.0.3",
+                "sebastian/resource-operations": "^1.0",
+                "sebastian/version": "^2.0.1"
+            },
+            "conflict": {
+                "phpdocumentor/reflection-docblock": "3.0.2",
+                "phpunit/dbunit": "<3.0"
+            },
+            "require-dev": {
+                "ext-pdo": "*"
             },
             "suggest": {
-                "phpunit/php-invoker": "~1.1"
+                "ext-xdebug": "*",
+                "phpunit/php-invoker": "^1.1"
             },
             "bin": [
                 "phpunit"
@@ -4204,7 +4364,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "4.8.x-dev"
+                    "dev-master": "6.5.x-dev"
                 }
             },
             "autoload": {
@@ -4230,30 +4390,33 @@
                 "testing",
                 "xunit"
             ],
-            "time": "2017-06-21T08:07:12+00:00"
+            "time": "2019-02-01T05:22:47+00:00"
         },
         {
             "name": "phpunit/phpunit-mock-objects",
-            "version": "2.3.8",
+            "version": "5.0.10",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit-mock-objects.git",
-                "reference": "ac8e7a3db35738d56ee9a76e78a4e03d97628983"
+                "reference": "cd1cf05c553ecfec36b170070573e540b67d3f1f"
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             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit-mock-objects/zipball/ac8e7a3db35738d56ee9a76e78a4e03d97628983",
-                "reference": "ac8e7a3db35738d56ee9a76e78a4e03d97628983",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit-mock-objects/zipball/cd1cf05c553ecfec36b170070573e540b67d3f1f",
+                "reference": "cd1cf05c553ecfec36b170070573e540b67d3f1f",
                 "shasum": ""
             },
             "require": {
-                "doctrine/instantiator": "^1.0.2",
-                "php": ">=5.3.3",
-                "phpunit/php-text-template": "~1.2",
-                "sebastian/exporter": "~1.2"
+                "doctrine/instantiator": "^1.0.5",
+                "php": "^7.0",
+                "phpunit/php-text-template": "^1.2.1",
+                "sebastian/exporter": "^3.1"
+            },
+            "conflict": {
+                "phpunit/phpunit": "<6.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.4"
+                "phpunit/phpunit": "^6.5.11"
             },
             "suggest": {
                 "ext-soap": "*"
@@ -4261,7 +4424,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.3.x-dev"
+                    "dev-master": "5.0.x-dev"
                 }
             },
             "autoload": {
@@ -4276,7 +4439,7 @@
             "authors": [
                 {
                     "name": "Sebastian Bergmann",
-                    "email": "sb@sebastian-bergmann.de",
+                    "email": "sebastian@phpunit.de",
                     "role": "lead"
                 }
             ],
@@ -4287,34 +4450,79 @@
                 "xunit"
             ],
             "abandoned": true,
-            "time": "2015-10-02T06:51:40+00:00"
+            "time": "2018-08-09T05:50:03+00:00"
+        },
+        {
+            "name": "sebastian/code-unit-reverse-lookup",
+            "version": "1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/code-unit-reverse-lookup.git",
+                "reference": "4419fcdb5eabb9caa61a27c7a1db532a6b55dd18"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/code-unit-reverse-lookup/zipball/4419fcdb5eabb9caa61a27c7a1db532a6b55dd18",
+                "reference": "4419fcdb5eabb9caa61a27c7a1db532a6b55dd18",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.6 || ^7.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^5.7 || ^6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Looks up which function or method a line of code belongs to",
+            "homepage": "https://github.com/sebastianbergmann/code-unit-reverse-lookup/",
+            "time": "2017-03-04T06:30:41+00:00"
         },
         {
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-            "version": "1.2.4",
+            "version": "2.1.3",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/comparator.git",
-                "reference": "2b7424b55f5047b47ac6e5ccb20b2aea4011d9be"
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-                "php": ">=5.3.3",
-                "sebastian/diff": "~1.2",
-                "sebastian/exporter": "~1.2 || ~2.0"
+                "php": "^7.0",
+                "sebastian/diff": "^2.0 || ^3.0",
+                "sebastian/exporter": "^3.1"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.4"
+                "phpunit/phpunit": "^6.4"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.2.x-dev"
+                    "dev-master": "2.1.x-dev"
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@@ -4345,38 +4553,38 @@
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             ],
             "description": "Provides the functionality to compare PHP values for equality",
-            "homepage": "http://www.github.com/sebastianbergmann/comparator",
+            "homepage": "https://github.com/sebastianbergmann/comparator",
             "keywords": [
                 "comparator",
                 "compare",
                 "equality"
             ],
-            "time": "2017-01-29T09:50:25+00:00"
+            "time": "2018-02-01T13:46:46+00:00"
         },
         {
             "name": "sebastian/diff",
-            "version": "1.4.3",
+            "version": "2.0.1",
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                 "url": "https://github.com/sebastianbergmann/diff.git",
-                "reference": "7f066a26a962dbe58ddea9f72a4e82874a3975a4"
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             },
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-                "php": "^5.3.3 || ^7.0"
+                "php": "^7.0"
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             "require-dev": {
-                "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.0"
+                "phpunit/phpunit": "^6.2"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.4-dev"
+                    "dev-master": "2.0-dev"
                 }
             },
             "autoload": {
@@ -4403,32 +4611,32 @@
             "keywords": [
                 "diff"
             ],
-            "time": "2017-05-22T07:24:03+00:00"
+            "time": "2017-08-03T08:09:46+00:00"
         },
         {
             "name": "sebastian/environment",
-            "version": "1.3.8",
+            "version": "3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/environment.git",
-                "reference": "be2c607e43ce4c89ecd60e75c6a85c126e754aea"
+                "reference": "cd0871b3975fb7fc44d11314fd1ee20925fce4f5"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/environment/zipball/be2c607e43ce4c89ecd60e75c6a85c126e754aea",
-                "reference": "be2c607e43ce4c89ecd60e75c6a85c126e754aea",
+                "url": "https://api.github.com/repos/sebastianbergmann/environment/zipball/cd0871b3975fb7fc44d11314fd1ee20925fce4f5",
+                "reference": "cd0871b3975fb7fc44d11314fd1ee20925fce4f5",
                 "shasum": ""
             },
             "require": {
-                "php": "^5.3.3 || ^7.0"
+                "php": "^7.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "^4.8 || ^5.0"
+                "phpunit/phpunit": "^6.1"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.3.x-dev"
+                    "dev-master": "3.1.x-dev"
                 }
             },
             "autoload": {
@@ -4453,34 +4661,34 @@
                 "environment",
                 "hhvm"
             ],
-            "time": "2016-08-18T05:49:44+00:00"
+            "time": "2017-07-01T08:51:00+00:00"
         },
         {
             "name": "sebastian/exporter",
-            "version": "1.2.2",
+            "version": "3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/exporter.git",
-                "reference": "42c4c2eec485ee3e159ec9884f95b431287edde4"
+                "reference": "234199f4528de6d12aaa58b612e98f7d36adb937"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/exporter/zipball/42c4c2eec485ee3e159ec9884f95b431287edde4",
-                "reference": "42c4c2eec485ee3e159ec9884f95b431287edde4",
+                "url": "https://api.github.com/repos/sebastianbergmann/exporter/zipball/234199f4528de6d12aaa58b612e98f7d36adb937",
+                "reference": "234199f4528de6d12aaa58b612e98f7d36adb937",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.3",
-                "sebastian/recursion-context": "~1.0"
+                "php": "^7.0",
+                "sebastian/recursion-context": "^3.0"
             },
             "require-dev": {
                 "ext-mbstring": "*",
-                "phpunit/phpunit": "~4.4"
+                "phpunit/phpunit": "^6.0"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.3.x-dev"
+                    "dev-master": "3.1.x-dev"
                 }
             },
             "autoload": {
@@ -4520,27 +4728,27 @@
                 "export",
                 "exporter"
             ],
-            "time": "2016-06-17T09:04:28+00:00"
+            "time": "2017-04-03T13:19:02+00:00"
         },
         {
             "name": "sebastian/global-state",
-            "version": "1.1.1",
+            "version": "2.0.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/global-state.git",
-                "reference": "bc37d50fea7d017d3d340f230811c9f1d7280af4"
+                "reference": "e8ba02eed7bbbb9e59e43dedd3dddeff4a56b0c4"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/global-state/zipball/bc37d50fea7d017d3d340f230811c9f1d7280af4",
-                "reference": "bc37d50fea7d017d3d340f230811c9f1d7280af4",
+                "url": "https://api.github.com/repos/sebastianbergmann/global-state/zipball/e8ba02eed7bbbb9e59e43dedd3dddeff4a56b0c4",
+                "reference": "e8ba02eed7bbbb9e59e43dedd3dddeff4a56b0c4",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.3"
+                "php": "^7.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.2"
+                "phpunit/phpunit": "^6.0"
             },
             "suggest": {
                 "ext-uopz": "*"
@@ -4548,7 +4756,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.0-dev"
+                    "dev-master": "2.0-dev"
                 }
             },
             "autoload": {
@@ -4571,32 +4779,124 @@
             "keywords": [
                 "global state"
             ],
-            "time": "2015-10-12T03:26:01+00:00"
+            "time": "2017-04-27T15:39:26+00:00"
+        },
+        {
+            "name": "sebastian/object-enumerator",
+            "version": "3.0.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/object-enumerator.git",
+                "reference": "7cfd9e65d11ffb5af41198476395774d4c8a84c5"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/object-enumerator/zipball/7cfd9e65d11ffb5af41198476395774d4c8a84c5",
+                "reference": "7cfd9e65d11ffb5af41198476395774d4c8a84c5",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.0",
+                "sebastian/object-reflector": "^1.1.1",
+                "sebastian/recursion-context": "^3.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Traverses array structures and object graphs to enumerate all referenced objects",
+            "homepage": "https://github.com/sebastianbergmann/object-enumerator/",
+            "time": "2017-08-03T12:35:26+00:00"
+        },
+        {
+            "name": "sebastian/object-reflector",
+            "version": "1.1.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/object-reflector.git",
+                "reference": "773f97c67f28de00d397be301821b06708fca0be"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/object-reflector/zipball/773f97c67f28de00d397be301821b06708fca0be",
+                "reference": "773f97c67f28de00d397be301821b06708fca0be",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.1-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Allows reflection of object attributes, including inherited and non-public ones",
+            "homepage": "https://github.com/sebastianbergmann/object-reflector/",
+            "time": "2017-03-29T09:07:27+00:00"
         },
         {
             "name": "sebastian/recursion-context",
-            "version": "1.0.5",
+            "version": "3.0.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/recursion-context.git",
-                "reference": "b19cc3298482a335a95f3016d2f8a6950f0fbcd7"
+                "reference": "5b0cd723502bac3b006cbf3dbf7a1e3fcefe4fa8"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/recursion-context/zipball/b19cc3298482a335a95f3016d2f8a6950f0fbcd7",
-                "reference": "b19cc3298482a335a95f3016d2f8a6950f0fbcd7",
+                "url": "https://api.github.com/repos/sebastianbergmann/recursion-context/zipball/5b0cd723502bac3b006cbf3dbf7a1e3fcefe4fa8",
+                "reference": "5b0cd723502bac3b006cbf3dbf7a1e3fcefe4fa8",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.3"
+                "php": "^7.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.4"
+                "phpunit/phpunit": "^6.0"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.0.x-dev"
+                    "dev-master": "3.0.x-dev"
                 }
             },
             "autoload": {
@@ -4624,23 +4924,73 @@
             ],
             "description": "Provides functionality to recursively process PHP variables",
             "homepage": "http://www.github.com/sebastianbergmann/recursion-context",
-            "time": "2016-10-03T07:41:43+00:00"
+            "time": "2017-03-03T06:23:57+00:00"
+        },
+        {
+            "name": "sebastian/resource-operations",
+            "version": "1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/resource-operations.git",
+                "reference": "ce990bb21759f94aeafd30209e8cfcdfa8bc3f52"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/resource-operations/zipball/ce990bb21759f94aeafd30209e8cfcdfa8bc3f52",
+                "reference": "ce990bb21759f94aeafd30209e8cfcdfa8bc3f52",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.6.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Provides a list of PHP built-in functions that operate on resources",
+            "homepage": "https://www.github.com/sebastianbergmann/resource-operations",
+            "time": "2015-07-28T20:34:47+00:00"
         },
         {
             "name": "sebastian/version",
-            "version": "1.0.6",
+            "version": "2.0.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/version.git",
-                "reference": "58b3a85e7999757d6ad81c787a1fbf5ff6c628c6"
+                "reference": "99732be0ddb3361e16ad77b68ba41efc8e979019"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/version/zipball/58b3a85e7999757d6ad81c787a1fbf5ff6c628c6",
-                "reference": "58b3a85e7999757d6ad81c787a1fbf5ff6c628c6",
+                "url": "https://api.github.com/repos/sebastianbergmann/version/zipball/99732be0ddb3361e16ad77b68ba41efc8e979019",
+                "reference": "99732be0ddb3361e16ad77b68ba41efc8e979019",
                 "shasum": ""
             },
+            "require": {
+                "php": ">=5.6"
+            },
             "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
             "autoload": {
                 "classmap": [
                     "src/"
@@ -4659,7 +5009,7 @@
             ],
             "description": "Library that helps with managing the version number of Git-hosted PHP projects",
             "homepage": "https://github.com/sebastianbergmann/version",
-            "time": "2015-06-21T13:59:46+00:00"
+            "time": "2016-10-03T07:35:21+00:00"
         },
         {
             "name": "squizlabs/php_codesniffer",
@@ -4943,6 +5293,46 @@
             "description": "Symfony PHPUnit Bridge",
             "homepage": "https://symfony.com",
             "time": "2019-04-16T09:03:16+00:00"
+        },
+        {
+            "name": "theseer/tokenizer",
+            "version": "1.1.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/theseer/tokenizer.git",
+                "reference": "1c42705be2b6c1de5904f8afacef5895cab44bf8"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/theseer/tokenizer/zipball/1c42705be2b6c1de5904f8afacef5895cab44bf8",
+                "reference": "1c42705be2b6c1de5904f8afacef5895cab44bf8",
+                "shasum": ""
+            },
+            "require": {
+                "ext-dom": "*",
+                "ext-tokenizer": "*",
+                "ext-xmlwriter": "*",
+                "php": "^7.0"
+            },
+            "type": "library",
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Arne Blankerts",
+                    "email": "arne@blankerts.de",
+                    "role": "Developer"
+                }
+            ],
+            "description": "A small library for converting tokenized PHP source code into XML and potentially other formats",
+            "time": "2019-04-04T09:56:43+00:00"
         }
     ],
     "aliases": [],
diff --git a/core/composer.json b/core/composer.json
index 2af439826fe4f82316b706c5e910f93d1cbe0fcc..e5de4f6b2cefcc61e270204acebee0c9b6b2eff4 100644
--- a/core/composer.json
+++ b/core/composer.json
@@ -60,7 +60,7 @@
         "jcalderonzumba/gastonjs": "^1.0.2",
         "jcalderonzumba/mink-phantomjs-driver": "^0.3.1",
         "mikey179/vfsstream": "^1.2",
-        "phpunit/phpunit": "^4.8.35 || ^6.5",
+        "phpunit/phpunit": "^6.5",
         "phpspec/prophecy": "^1.7",
         "symfony/css-selector": "^3.4.0",
         "symfony/phpunit-bridge": "^3.4.3",
diff --git a/core/lib/Drupal/Core/Composer/Composer.php b/core/lib/Drupal/Core/Composer/Composer.php
index acdf6faa9c2f80a30ae9313c00a8fa35e047be09..df4b72368e5b437a152722b4a04d483ac9cdd35f 100644
--- a/core/lib/Drupal/Core/Composer/Composer.php
+++ b/core/lib/Drupal/Core/Composer/Composer.php
@@ -149,48 +149,6 @@ public static function ensureHtaccess(Event $event) {
     }
   }
 
-  /**
-   * Fires the drupal-phpunit-upgrade script event if necessary.
-   *
-   * @param \Composer\Script\Event $event
-   */
-  public static function upgradePHPUnit(Event $event) {
-    $repository = $event->getComposer()->getRepositoryManager()->getLocalRepository();
-    // This is, essentially, a null constraint. We only care whether the package
-    // is present in the vendor directory yet, but findPackage() requires it.
-    $constraint = new Constraint('>', '');
-    $phpunit_package = $repository->findPackage('phpunit/phpunit', $constraint);
-    if (!$phpunit_package) {
-      // There is nothing to do. The user is probably installing using the
-      // --no-dev flag.
-      return;
-    }
-
-    // If the PHP version is 7.0 or above and PHPUnit is less than version 6
-    // call the drupal-phpunit-upgrade script to upgrade PHPUnit.
-    if (!static::upgradePHPUnitCheck($phpunit_package->getVersion())) {
-      $event->getComposer()
-        ->getEventDispatcher()
-        ->dispatchScript('drupal-phpunit-upgrade');
-    }
-  }
-
-  /**
-   * Determines if PHPUnit needs to be upgraded.
-   *
-   * This method is located in this file because it is possible that it is
-   * called before the autoloader is available.
-   *
-   * @param string $phpunit_version
-   *   The PHPUnit version string.
-   *
-   * @return bool
-   *   TRUE if the PHPUnit needs to be upgraded, FALSE if not.
-   */
-  public static function upgradePHPUnitCheck($phpunit_version) {
-    return !(version_compare(PHP_MAJOR_VERSION . '.' . PHP_MINOR_VERSION, '7.0') >= 0 && version_compare($phpunit_version, '6.1') < 0);
-  }
-
   /**
    * Remove possibly problematic test files from vendored projects.
    *
diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 42bc5e8b6c14ff32b2e3f070d15158073f564e9d..fdc5157292471e85293d994e0b78a5f6971fb398 100755
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -9,7 +9,6 @@
 use Drupal\Component\Utility\Html;
 use Drupal\Component\Utility\Timer;
 use Drupal\Component\Uuid\Php;
-use Drupal\Core\Composer\Composer;
 use Drupal\Core\Asset\AttachedAssets;
 use Drupal\Core\Database\Database;
 use Drupal\Core\File\Exception\FileException;
@@ -148,10 +147,6 @@
 else {
   $phpunit_version = Version::id();
 }
-if (!Composer::upgradePHPUnitCheck($phpunit_version)) {
-  simpletest_script_print_error("PHPUnit testing framework version 6 or greater is required when running on PHP 7.0 or greater. Run the command 'composer run-script drupal-phpunit-upgrade' in order to fix this.");
-  exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
-}
 
 $test_list = simpletest_script_get_test_list();
 
diff --git a/core/tests/bootstrap.php b/core/tests/bootstrap.php
index 3dad6142e25126bba3f3a2033498c9e126c70a77..7a707472730b2fd876529db67506ef8616942b93 100644
--- a/core/tests/bootstrap.php
+++ b/core/tests/bootstrap.php
@@ -8,7 +8,6 @@
  */
 
 use Drupal\Component\Assertion\Handle;
-use Drupal\Core\Composer\Composer;
 use PHPUnit\Runner\Version;
 
 /**
@@ -159,11 +158,6 @@ function drupal_phpunit_populate_class_loader() {
 else {
   $phpunit_version = Version::id();
 }
-if (!Composer::upgradePHPUnitCheck($phpunit_version)) {
-  $message = "PHPUnit testing framework version 6 or greater is required when running on PHP 7.0 or greater. Run the command 'composer run-script drupal-phpunit-upgrade' in order to fix this.";
-  echo "\033[31m" . $message . "\n\033[0m";
-  exit(1);
-}
 
 // Set sane locale settings, to ensure consistent string, dates, times and
 // numbers handling.