diff --git a/.github/workflows/build-test-measure.yml b/.github/workflows/build-test-measure.yml
index 05717da4a..abf610982 100644
--- a/.github/workflows/build-test-measure.yml
+++ b/.github/workflows/build-test-measure.yml
@@ -87,18 +87,7 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: ${{ steps.nvm.outputs.NVMRC }}
-
-      - name: Get npm cache directory
-        id: npm-cache
-        run: echo "::set-output name=dir::$(npm config get cache)"
-
-      - name: Configure npm cache
-        uses: actions/cache@v2
-        with:
-          path: ${{ steps.npm-cache.outputs.dir }}
-          key: ${{ runner.os }}-npm-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-npm-
+          cache: npm
 
       - name: Install Node dependencies
         run: npm ci
@@ -295,6 +284,7 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: ${{ steps.nvm.outputs.NVMRC }}
+          cache: npm
 
       - name: Get Composer Cache Directory
         id: composer-cache
@@ -311,18 +301,6 @@ jobs:
       - name: Install Composer dependencies
         run: composer install --prefer-dist --ignore-platform-reqs --no-progress --no-interaction
 
-      - name: Get npm cache directory
-        id: npm-cache
-        run: echo "::set-output name=dir::$(npm config get cache)"
-
-      - name: Configure npm cache
-        uses: actions/cache@v2
-        with:
-          path: ${{ steps.npm-cache.outputs.dir }}
-          key: ${{ runner.os }}-npm-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-npm-
-
       - name: Install Node dependencies
         run: npm ci
         env:
@@ -339,9 +317,6 @@ jobs:
       - name: Install WP tests
         run: bash bin/ci/install-wp-tests.sh wordpress_test root '' 127.0.0.1:${{ job.services.mysql.ports['3306'] }} ${{ matrix.wp }} true
 
-      - name: Post install of WP tests
-        run: bash bin/ci/after-wp-install.sh ${{ matrix.wp }} /tmp/wordpress-tests
-
       - name: Setup PCOV
         if: ${{ matrix.coverage == true }}
         # phpdocumentor/reflection has to be removed as it makes use of an outdated dependency, making pcov/clobber
@@ -366,7 +341,7 @@ jobs:
 
       - name: Upload code coverage report
         if: ${{ matrix.coverage == true }}
-        uses: codecov/codecov-action@v1.5.2
+        uses: codecov/codecov-action@v2.0.2
         with:
           file: ${{ env.WP_CORE_DIR }}/src/wp-content/plugins/pwa/build/logs/clover.xml
           flags: php,unit
diff --git a/bin/ci/after-wp-install.sh b/bin/ci/after-wp-install.sh
deleted file mode 100755
index 92467c22d..000000000
--- a/bin/ci/after-wp-install.sh
+++ /dev/null
@@ -1,51 +0,0 @@
-#!/bin/bash
-
-set -e
-
-WP_VERSION=$1
-WP_TESTS_DIR=$2
-
-if [[ -z $WP_VERSION ]]; then
-	echo "usage: $0 <wp-version>"
-	exit 1
-fi
-
-if [[ $(php -r "echo PHP_VERSION;") == 8.0* ]]; then
-	echo "Installing compatible PHPUnit for use with PHP 8..."
-
-	DIFF=$(
-		cat <<-EOF
-diff --git a/composer.json b/composer.json
-index 562c54a..0c6a247 100644
---- a/composer.json
-+++ b/composer.json
-@@ -31,6 +31,20 @@
-       }
-     }
-   },
-+  "autoload-dev": {
-+     "files": [
-+       "${WP_TESTS_DIR}/includes/phpunit7/MockObject/Builder/NamespaceMatch.php",
-+       "${WP_TESTS_DIR}/includes/phpunit7/MockObject/Builder/ParametersMatch.php",
-+       "${WP_TESTS_DIR}/includes/phpunit7/MockObject/InvocationMocker.php",
-+       "${WP_TESTS_DIR}/includes/phpunit7/MockObject/MockMethod.php"
-+     ],
-+     "exclude-from-classmap": [
-+       "vendor/phpunit/phpunit/src/Framework/MockObject/Builder/NamespaceMatch.php",
-+       "vendor/phpunit/phpunit/src/Framework/MockObject/Builder/ParametersMatch.php",
-+       "vendor/phpunit/phpunit/src/Framework/MockObject/InvocationMocker.php",
-+       "vendor/phpunit/phpunit/src/Framework/MockObject/MockMethod.php"
-+     ]
-+  },
-   "minimum-stability": "dev",
-   "prefer-stable": true,
-   "scripts": {
-		EOF
-	)
-
-	echo "${DIFF}" | git apply -
-	composer require --dev --ignore-platform-reqs --update-with-dependencies phpunit/phpunit:^7.5
-
-	PATH="$(composer config bin-dir --absolute):$PATH"
-	echo "done"
-fi
diff --git a/composer.json b/composer.json
index 562c54a6f..7161c88a1 100644
--- a/composer.json
+++ b/composer.json
@@ -11,10 +11,10 @@
     "automattic/vipwpcs": "^2.2",
     "civicrm/composer-downloads-plugin": "^3.0",
     "dealerdirect/phpcodesniffer-composer-installer": "0.7.1",
-    "phpcompatibility/phpcompatibility-wp": "2.1.1",
     "php-stubs/wordpress-stubs": "^5.3.2",
-    "phpunit/phpunit": "^5.7 || ^6.5 || ^7.5",
-    "wp-coding-standards/wpcs": "2.3.0"
+    "phpcompatibility/phpcompatibility-wp": "2.1.1",
+    "wp-coding-standards/wpcs": "2.3.0",
+    "yoast/wp-test-utils": "^0.2.2"
   },
   "config": {
     "platform": {
diff --git a/composer.lock b/composer.lock
index 04acbfc13..635e5a837 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,9 +4,57 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "c158d1680b3e630ead388b5f7a494b8b",
+    "content-hash": "df8e181c3517e1f4dc21583c6699d2c8",
     "packages": [],
     "packages-dev": [
+        {
+            "name": "antecedent/patchwork",
+            "version": "2.1.15",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/antecedent/patchwork.git",
+                "reference": "0430ceaac7f447f1778c199ec19d7e4362a6f961"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/antecedent/patchwork/zipball/0430ceaac7f447f1778c199ec19d7e4362a6f961",
+                "reference": "0430ceaac7f447f1778c199ec19d7e4362a6f961",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": ">=4"
+            },
+            "type": "library",
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Ignas Rudaitis",
+                    "email": "ignas.rudaitis@gmail.com"
+                }
+            ],
+            "description": "Method redefinition (monkey-patching) functionality for PHP.",
+            "homepage": "http://patchwork2.org/",
+            "keywords": [
+                "aop",
+                "aspect",
+                "interception",
+                "monkeypatching",
+                "redefinition",
+                "runkit",
+                "testing"
+            ],
+            "support": {
+                "issues": "https://github.com/antecedent/patchwork/issues",
+                "source": "https://github.com/antecedent/patchwork/tree/2.1.15"
+            },
+            "time": "2021-08-22T08:00:13+00:00"
+        },
         {
             "name": "automattic/vipwpcs",
             "version": "2.3.2",
@@ -59,6 +107,76 @@
             },
             "time": "2021-04-28T16:41:50+00:00"
         },
+        {
+            "name": "brain/monkey",
+            "version": "2.6.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Brain-WP/BrainMonkey.git",
+                "reference": "7042140000b4b18034c0c0010d86274a00f25442"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Brain-WP/BrainMonkey/zipball/7042140000b4b18034c0c0010d86274a00f25442",
+                "reference": "7042140000b4b18034c0c0010d86274a00f25442",
+                "shasum": ""
+            },
+            "require": {
+                "antecedent/patchwork": "^2.0",
+                "mockery/mockery": ">=0.9 <2",
+                "php": ">=5.6.0"
+            },
+            "require-dev": {
+                "dealerdirect/phpcodesniffer-composer-installer": "^0.6 || ^0.7",
+                "phpcompatibility/php-compatibility": "^9.3.0",
+                "phpunit/phpunit": "^5.7.9 || ^6.0 || ^7.0 || ^8.0 || ^9.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-version/1": "1.x-dev",
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Brain\\Monkey\\": "src/"
+                },
+                "files": [
+                    "inc/api.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Giuseppe Mazzapica",
+                    "email": "giuseppe.mazzapica@gmail.com",
+                    "homepage": "https://gmazzap.me",
+                    "role": "Developer"
+                }
+            ],
+            "description": "Mocking utility for PHP functions and WordPress plugin API",
+            "keywords": [
+                "Monkey Patching",
+                "interception",
+                "mock",
+                "mock functions",
+                "mockery",
+                "patchwork",
+                "redefinition",
+                "runkit",
+                "test",
+                "testing"
+            ],
+            "support": {
+                "issues": "https://github.com/Brain-WP/BrainMonkey/issues",
+                "source": "https://github.com/Brain-WP/BrainMonkey"
+            },
+            "time": "2020-10-13T17:56:14+00:00"
+        },
         {
             "name": "civicrm/composer-downloads-plugin",
             "version": "v3.0.1",
@@ -241,6 +359,126 @@
             },
             "time": "2015-06-14T21:17:01+00:00"
         },
+        {
+            "name": "hamcrest/hamcrest-php",
+            "version": "v2.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/hamcrest/hamcrest-php.git",
+                "reference": "8c3d0a3f6af734494ad8f6fbbee0ba92422859f3"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/hamcrest/hamcrest-php/zipball/8c3d0a3f6af734494ad8f6fbbee0ba92422859f3",
+                "reference": "8c3d0a3f6af734494ad8f6fbbee0ba92422859f3",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.3|^7.0|^8.0"
+            },
+            "replace": {
+                "cordoval/hamcrest-php": "*",
+                "davedevelopment/hamcrest-php": "*",
+                "kodova/hamcrest-php": "*"
+            },
+            "require-dev": {
+                "phpunit/php-file-iterator": "^1.4 || ^2.0",
+                "phpunit/phpunit": "^4.8.36 || ^5.7 || ^6.5 || ^7.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.1-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "hamcrest"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "description": "This is the PHP port of Hamcrest Matchers",
+            "keywords": [
+                "test"
+            ],
+            "support": {
+                "issues": "https://github.com/hamcrest/hamcrest-php/issues",
+                "source": "https://github.com/hamcrest/hamcrest-php/tree/v2.0.1"
+            },
+            "time": "2020-07-09T08:09:16+00:00"
+        },
+        {
+            "name": "mockery/mockery",
+            "version": "1.3.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/mockery/mockery.git",
+                "reference": "31467aeb3ca3188158613322d66df81cedd86626"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/mockery/mockery/zipball/31467aeb3ca3188158613322d66df81cedd86626",
+                "reference": "31467aeb3ca3188158613322d66df81cedd86626",
+                "shasum": ""
+            },
+            "require": {
+                "hamcrest/hamcrest-php": "^2.0.1",
+                "lib-pcre": ">=7.0",
+                "php": ">=5.6.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^5.7.10|^6.5|^7.5|^8.5|^9.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.3.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-0": {
+                    "Mockery": "library/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Pádraic Brady",
+                    "email": "padraic.brady@gmail.com",
+                    "homepage": "http://blog.astrumfutura.com"
+                },
+                {
+                    "name": "Dave Marshall",
+                    "email": "dave.marshall@atstsolutions.co.uk",
+                    "homepage": "http://davedevelopment.co.uk"
+                }
+            ],
+            "description": "Mockery is a simple yet flexible PHP mock object framework",
+            "homepage": "https://github.com/mockery/mockery",
+            "keywords": [
+                "BDD",
+                "TDD",
+                "library",
+                "mock",
+                "mock objects",
+                "mockery",
+                "stub",
+                "test",
+                "test double",
+                "testing"
+            ],
+            "support": {
+                "issues": "https://github.com/mockery/mockery/issues",
+                "source": "https://github.com/mockery/mockery/tree/1.3.4"
+            },
+            "time": "2021-02-24T09:51:00+00:00"
+        },
         {
             "name": "myclabs/deep-copy",
             "version": "1.7.0",
@@ -2112,6 +2350,135 @@
                 "wiki": "https://github.com/WordPress/WordPress-Coding-Standards/wiki"
             },
             "time": "2020-05-13T23:57:56+00:00"
+        },
+        {
+            "name": "yoast/phpunit-polyfills",
+            "version": "1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Yoast/PHPUnit-Polyfills.git",
+                "reference": "f014fb21c2b0038fd329515d59025af42fb98715"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Yoast/PHPUnit-Polyfills/zipball/f014fb21c2b0038fd329515d59025af42fb98715",
+                "reference": "f014fb21c2b0038fd329515d59025af42fb98715",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4",
+                "phpunit/phpunit": "^4.8.36 || ^5.7.21 || ^6.0 || ^7.0 || ^8.0 || ^9.0"
+            },
+            "require-dev": {
+                "php-parallel-lint/php-console-highlighter": "^0.5",
+                "php-parallel-lint/php-parallel-lint": "^1.3.0",
+                "yoast/yoastcs": "^2.1.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "1.x-dev",
+                    "dev-develop": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "phpunitpolyfills-autoload.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Team Yoast",
+                    "email": "support@yoast.com",
+                    "homepage": "https://yoast.com"
+                },
+                {
+                    "name": "Contributors",
+                    "homepage": "https://github.com/Yoast/PHPUnit-Polyfills/graphs/contributors"
+                }
+            ],
+            "description": "Set of polyfills for changed PHPUnit functionality to allow for creating PHPUnit cross-version compatible tests",
+            "homepage": "https://github.com/Yoast/PHPUnit-Polyfills",
+            "keywords": [
+                "phpunit",
+                "polyfill",
+                "testing"
+            ],
+            "support": {
+                "issues": "https://github.com/Yoast/PHPUnit-Polyfills/issues",
+                "source": "https://github.com/Yoast/PHPUnit-Polyfills"
+            },
+            "time": "2021-08-09T16:28:08+00:00"
+        },
+        {
+            "name": "yoast/wp-test-utils",
+            "version": "0.2.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Yoast/wp-test-utils.git",
+                "reference": "896f7640d86162ff7a0dc6ce59f8837f284521c5"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Yoast/wp-test-utils/zipball/896f7640d86162ff7a0dc6ce59f8837f284521c5",
+                "reference": "896f7640d86162ff7a0dc6ce59f8837f284521c5",
+                "shasum": ""
+            },
+            "require": {
+                "brain/monkey": "^2.6.0",
+                "php": ">=5.6",
+                "yoast/phpunit-polyfills": "^1.0.0"
+            },
+            "require-dev": {
+                "php-parallel-lint/php-console-highlighter": "^0.5",
+                "php-parallel-lint/php-parallel-lint": "^1.3.0",
+                "yoast/yoastcs": "^2.1.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "1.x-dev",
+                    "dev-develop": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Team Yoast",
+                    "email": "support@yoast.com",
+                    "homepage": "https://yoast.com"
+                },
+                {
+                    "name": "Contributors",
+                    "homepage": "https://github.com/Yoast/wp-test-utils/graphs/contributors"
+                }
+            ],
+            "description": "PHPUnit cross-version compatibility layer for testing plugins and themes build for WordPress",
+            "homepage": "https://github.com/Yoast/wp-test-utils/",
+            "keywords": [
+                "brainmonkey",
+                "integration-testing",
+                "phpunit",
+                "unit-testing",
+                "wordpress"
+            ],
+            "support": {
+                "issues": "https://github.com/Yoast/wp-test-utils/issues",
+                "source": "https://github.com/Yoast/wp-test-utils"
+            },
+            "time": "2021-06-21T03:45:02+00:00"
         }
     ],
     "aliases": [],
diff --git a/tests/components/test-class-wp-service-worker-caching-routes.php b/tests/components/test-class-wp-service-worker-caching-routes.php
index 9945d83f8..ebaad84e3 100644
--- a/tests/components/test-class-wp-service-worker-caching-routes.php
+++ b/tests/components/test-class-wp-service-worker-caching-routes.php
@@ -5,12 +5,14 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Caching_Routes.
  *
  * @coversDefaultClass WP_Service_Worker_Caching_Routes
  */
-class Test_WP_Service_Worker_Caching_Routes extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Caching_Routes extends TestCase {
 
 	/**
 	 * Tested instance.
@@ -280,14 +282,14 @@ public function test_prepare_strategy_args_for_js_export() {
 			)
 		);
 
-		$this->assertContains( WP_Service_Worker_Caching_Routes::STRATEGY_NETWORK_FIRST, $prepared );
-		$this->assertContains( '"strategy":"NetworkFirst"', $prepared );
-		$this->assertContains( '"networkTimeoutSeconds":2', $prepared );
-		$this->assertContains( '"cacheName":"bank-cash"', $prepared );
-		$this->assertContains( '{"maxEntries":4,"maxAgeSeconds":20}', $prepared );
-		$this->assertContains( 'broadcastUpdate', $prepared );
-		$this->assertContains( 'BroadcastUpdatePlugin', $prepared );
-		$this->assertContains( 'expiration', $prepared );
-		$this->assertContains( 'ExpirationPlugin', $prepared );
+		$this->assertStringContainsString( WP_Service_Worker_Caching_Routes::STRATEGY_NETWORK_FIRST, $prepared );
+		$this->assertStringContainsString( '"strategy":"NetworkFirst"', $prepared );
+		$this->assertStringContainsString( '"networkTimeoutSeconds":2', $prepared );
+		$this->assertStringContainsString( '"cacheName":"bank-cash"', $prepared );
+		$this->assertStringContainsString( '{"maxEntries":4,"maxAgeSeconds":20}', $prepared );
+		$this->assertStringContainsString( 'broadcastUpdate', $prepared );
+		$this->assertStringContainsString( 'BroadcastUpdatePlugin', $prepared );
+		$this->assertStringContainsString( 'expiration', $prepared );
+		$this->assertStringContainsString( 'ExpirationPlugin', $prepared );
 	}
 }
diff --git a/tests/components/test-class-wp-service-worker-core-asset-caching-component.php b/tests/components/test-class-wp-service-worker-core-asset-caching-component.php
index f11d5a345..daefc542d 100644
--- a/tests/components/test-class-wp-service-worker-core-asset-caching-component.php
+++ b/tests/components/test-class-wp-service-worker-core-asset-caching-component.php
@@ -5,12 +5,14 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Core_Asset_Caching_Component.
  *
  * @coversDefaultClass WP_Service_Worker_Core_Asset_Caching_Component
  */
-class Test_WP_Service_Worker_Core_Asset_Caching_Component extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Core_Asset_Caching_Component extends TestCase {
 
 	/**
 	 * Get data for test_serve.
diff --git a/tests/components/test-class-wp-service-worker-navigation-routing-component.php b/tests/components/test-class-wp-service-worker-navigation-routing-component.php
index c3fb7626c..db2f20eb4 100644
--- a/tests/components/test-class-wp-service-worker-navigation-routing-component.php
+++ b/tests/components/test-class-wp-service-worker-navigation-routing-component.php
@@ -5,12 +5,14 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Navigation_Routing_Component.
  *
  * @coversDefaultClass WP_Service_Worker_Navigation_Routing_Component
  */
-class Test_WP_Service_Worker_Navigation_Routing_Component extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Navigation_Routing_Component extends TestCase {
 
 	/**
 	 * Test registering a route.
diff --git a/tests/components/test-class-wp-service-worker-plugin-asset-caching-component.php b/tests/components/test-class-wp-service-worker-plugin-asset-caching-component.php
index db73abff9..ded66c491 100644
--- a/tests/components/test-class-wp-service-worker-plugin-asset-caching-component.php
+++ b/tests/components/test-class-wp-service-worker-plugin-asset-caching-component.php
@@ -5,12 +5,14 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Plugin_Asset_Caching_Component.
  *
  * @coversDefaultClass WP_Service_Worker_Plugin_Asset_Caching_Component
  */
-class Test_WP_Service_Worker_Plugin_Asset_Caching_Component extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Plugin_Asset_Caching_Component extends TestCase {
 
 	/**
 	 * Get data for test_serve.
diff --git a/tests/components/test-class-wp-service-worker-precaching-routes.php b/tests/components/test-class-wp-service-worker-precaching-routes.php
index a0ea57c25..377547073 100644
--- a/tests/components/test-class-wp-service-worker-precaching-routes.php
+++ b/tests/components/test-class-wp-service-worker-precaching-routes.php
@@ -5,12 +5,14 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Precaching_Routes.
  *
  * @coversDefaultClass WP_Service_Worker_Precaching_Routes
  */
-class Test_WP_Service_Worker_Precaching_Routes extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Precaching_Routes extends TestCase {
 
 	/**
 	 * Tested instance.
diff --git a/tests/components/test-class-wp-service-worker-theme-asset-caching-component.php b/tests/components/test-class-wp-service-worker-theme-asset-caching-component.php
index e22595ed8..66f1a3729 100644
--- a/tests/components/test-class-wp-service-worker-theme-asset-caching-component.php
+++ b/tests/components/test-class-wp-service-worker-theme-asset-caching-component.php
@@ -5,12 +5,14 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Theme_Asset_Caching_Component.
  *
  * @coversDefaultClass WP_Service_Worker_Theme_Asset_Caching_Component
  */
-class Test_WP_Service_Worker_Theme_Asset_Caching_Component extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Theme_Asset_Caching_Component extends TestCase {
 
 	/**
 	 * Get data for test_serve.
diff --git a/tests/components/test-class-wp-service-worker-uploaded-image-caching-component.php b/tests/components/test-class-wp-service-worker-uploaded-image-caching-component.php
index e936f0668..204fec5c6 100644
--- a/tests/components/test-class-wp-service-worker-uploaded-image-caching-component.php
+++ b/tests/components/test-class-wp-service-worker-uploaded-image-caching-component.php
@@ -5,12 +5,14 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Uploaded_Image_Caching_Component.
  *
  * @coversDefaultClass WP_Service_Worker_Uploaded_Image_Caching_Component
  */
-class Test_WP_Service_Worker_Uploaded_Image_Caching_Component extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Uploaded_Image_Caching_Component extends TestCase {
 
 	/**
 	 * Get data for test_serve.
diff --git a/tests/test-class-wp-service-worker-scripts.php b/tests/test-class-wp-service-worker-scripts.php
index 7c51c7bbc..b22a66ecf 100644
--- a/tests/test-class-wp-service-worker-scripts.php
+++ b/tests/test-class-wp-service-worker-scripts.php
@@ -5,10 +5,12 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Worker_Scripts.
  */
-class Test_WP_Service_Worker_Scripts extends WP_UnitTestCase {
+class Test_WP_Service_Worker_Scripts extends TestCase {
 
 	/**
 	 * Tested instance.
diff --git a/tests/test-class-wp-service-workers.php b/tests/test-class-wp-service-workers.php
index b8d174843..465eb5a69 100644
--- a/tests/test-class-wp-service-workers.php
+++ b/tests/test-class-wp-service-workers.php
@@ -5,10 +5,12 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Service_Workers.
  */
-class Test_WP_Service_Workers extends WP_UnitTestCase {
+class Test_WP_Service_Workers extends TestCase {
 
 	/**
 	 * Tested instance.
@@ -69,9 +71,9 @@ public function test_serve_request_front() {
 		$output = ob_get_clean();
 
 		$this->assertSame( 0, get_current_user_id() );
-		$this->assertContains( $this->return_foo_sw(), $output );
-		$this->assertContains( $this->return_bar_sw(), $output );
-		$this->assertNotContains( $this->return_baz_sw(), $output );
+		$this->assertStringContainsString( $this->return_foo_sw(), $output );
+		$this->assertStringContainsString( $this->return_bar_sw(), $output );
+		$this->assertStringNotContainsString( $this->return_baz_sw(), $output );
 		$this->assertTrue(
 			strpos( $output, $this->return_foo_sw() ) < strpos( $output, $this->return_bar_sw() )
 		);
@@ -96,9 +98,9 @@ public function test_serve_request_admin() {
 		$output = ob_get_clean();
 
 		$this->assertSame( 0, get_current_user_id() );
-		$this->assertContains( $this->return_foo_sw(), $output );
-		$this->assertNotContains( $this->return_bar_sw(), $output );
-		$this->assertContains( $this->return_baz_sw(), $output );
+		$this->assertStringContainsString( $this->return_foo_sw(), $output );
+		$this->assertStringNotContainsString( $this->return_bar_sw(), $output );
+		$this->assertStringContainsString( $this->return_baz_sw(), $output );
 		$this->assertTrue(
 			strpos( $output, $this->return_foo_sw() ) < strpos( $output, $this->return_baz_sw() )
 		);
@@ -124,7 +126,7 @@ public function test_serve_request_bad_src_callback() {
 		wp_service_workers()->serve_request();
 		$output = ob_get_clean();
 
-		$this->assertContains( 'Service worker src is invalid', $output );
+		$this->assertStringContainsString( 'Service worker src is invalid', $output );
 	}
 
 	/**
@@ -146,7 +148,7 @@ public function test_serve_request_bad_src_url() {
 		wp_service_workers()->serve_request();
 		$output = ob_get_clean();
 
-		$this->assertContains( 'Service worker src is invalid', $output );
+		$this->assertStringContainsString( 'Service worker src is invalid', $output );
 	}
 
 	/**
diff --git a/tests/test-class-wp-web-app-manifest.php b/tests/test-class-wp-web-app-manifest.php
index cdfadcc1a..6fd072f26 100644
--- a/tests/test-class-wp-web-app-manifest.php
+++ b/tests/test-class-wp-web-app-manifest.php
@@ -5,10 +5,12 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for class WP_Web_App_Manifest.
  */
-class Test_WP_Web_App_Manifest extends WP_UnitTestCase {
+class Test_WP_Web_App_Manifest extends TestCase {
 
 	/**
 	 * Tested instance.
@@ -112,7 +114,7 @@ public function test_manifest_link_and_meta() {
 		add_filter(
 			'apple_touch_startup_images',
 			function ( $images ) use ( $added_images ) {
-				$this->assertInternalType( 'array', $images );
+				$this->assertIsArray( $images );
 				$this->assertCount( 1, $images );
 				$images   = array_merge( $images, $added_images );
 				$images[] = array( 'bad' => 'yes' );
@@ -125,20 +127,20 @@ function ( $images ) use ( $added_images ) {
 		$output = ob_get_clean();
 
 		$this->assertSame( 3, substr_count( $output, '<link rel="apple-touch-startup-image"' ) );
-		$this->assertContains( sprintf( '<link rel="apple-touch-startup-image" href="%s">', esc_url( get_site_icon_url() ) ), $output );
+		$this->assertStringContainsString( sprintf( '<link rel="apple-touch-startup-image" href="%s">', esc_url( get_site_icon_url() ) ), $output );
 		foreach ( $added_images as $added_image ) {
 			$tag = sprintf( '<link rel="apple-touch-startup-image" href="%s"', esc_url( $added_image['href'] ) );
 			if ( isset( $added_image['media'] ) ) {
 				$tag .= sprintf( ' media="%s"', esc_attr( $added_image['media'] ) );
 			}
 			$tag .= '>';
-			$this->assertContains( $tag, $output );
+			$this->assertStringContainsString( $tag, $output );
 		}
 
-		$this->assertContains( '<link rel="manifest"', $output );
-		$this->assertContains( rest_url( WP_Web_App_Manifest::REST_NAMESPACE . WP_Web_App_Manifest::REST_ROUTE ), $output );
-		$this->assertContains( '<meta name="theme-color" content="', $output );
-		$this->assertContains( $this->instance->get_theme_color(), $output );
+		$this->assertStringContainsString( '<link rel="manifest"', $output );
+		$this->assertStringContainsString( rest_url( WP_Web_App_Manifest::REST_NAMESPACE . WP_Web_App_Manifest::REST_ROUTE ), $output );
+		$this->assertStringContainsString( '<meta name="theme-color" content="', $output );
+		$this->assertStringContainsString( $this->instance->get_theme_color(), $output );
 	}
 
 	/**
@@ -194,7 +196,7 @@ public function test_get_manifest() {
 		// Test that the filter at the end of the method overrides the value.
 		add_filter( 'web_app_manifest', array( $this, 'mock_manifest' ) );
 		$actual_manifest = $this->instance->get_manifest();
-		$this->assertContains( self::MOCK_THEME_COLOR, $actual_manifest['theme_color'] );
+		$this->assertStringContainsString( self::MOCK_THEME_COLOR, $actual_manifest['theme_color'] );
 	}
 
 	/**
diff --git a/tests/test-general-template.php b/tests/test-general-template.php
index 85e54c7e7..d4cb5a52c 100644
--- a/tests/test-general-template.php
+++ b/tests/test-general-template.php
@@ -5,10 +5,12 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for general-template.php.
  */
-class Test_General_Template extends WP_UnitTestCase {
+class Test_General_Template extends TestCase {
 
 	/**
 	 * Get data for testing wp_unauthenticate_error_template_requests().
diff --git a/tests/test-pwa.php b/tests/test-pwa.php
index 6af5da884..2624ac6a5 100644
--- a/tests/test-pwa.php
+++ b/tests/test-pwa.php
@@ -5,10 +5,12 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for pwa.php.
  */
-class Test_PWA extends WP_UnitTestCase {
+class Test_PWA extends TestCase {
 
 	/**
 	 * Test bootstrap.
diff --git a/tests/test-service-workers.php b/tests/test-service-workers.php
index 492a3adfb..4e9eb8090 100644
--- a/tests/test-service-workers.php
+++ b/tests/test-service-workers.php
@@ -5,10 +5,12 @@
  * @package PWA
  */
 
+use Yoast\WPTestUtils\WPIntegration\TestCase;
+
 /**
  * Tests for service worker functions.
  */
-class Test_Service_Workers_Includes extends WP_UnitTestCase {
+class Test_Service_Workers_Includes extends TestCase {
 
 	/**
 	 * Tear down.