diff --git a/automatic_updates_extensions/tests/src/Build/ModuleUpdateTest.php b/automatic_updates_extensions/tests/src/Build/ModuleUpdateTest.php
index f0c8425f05bfbac46bf45bdd5ba40fd9b97cfb5b..9354509868c9387f6dc9721f5e3a06e2036d6936 100644
--- a/automatic_updates_extensions/tests/src/Build/ModuleUpdateTest.php
+++ b/automatic_updates_extensions/tests/src/Build/ModuleUpdateTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates_extensions\Build;
 
 use Drupal\Tests\automatic_updates\Build\UpdateTestBase;
diff --git a/automatic_updates_extensions/tests/src/Functional/UpdaterFormTest.php b/automatic_updates_extensions/tests/src/Functional/UpdaterFormTest.php
index f6966cc691406d14a16b1651b7722e05bc75366c..ebacbd0bfb5795e4f89f8ebe7450ee0f0af1b17c 100644
--- a/automatic_updates_extensions/tests/src/Functional/UpdaterFormTest.php
+++ b/automatic_updates_extensions/tests/src/Functional/UpdaterFormTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates_extensions\Functional;
 
 use Drupal\automatic_updates_test\EventSubscriber\TestSubscriber1;
diff --git a/automatic_updates_extensions/tests/src/Kernel/ExtensionUpdaterTest.php b/automatic_updates_extensions/tests/src/Kernel/ExtensionUpdaterTest.php
index c23333401da8492b8afd36e8d5b2a3a5145e993c..78f55b2742bddfedc40a88d04b631b252884b455 100644
--- a/automatic_updates_extensions/tests/src/Kernel/ExtensionUpdaterTest.php
+++ b/automatic_updates_extensions/tests/src/Kernel/ExtensionUpdaterTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates_extensions\Kernel;
 
 use Drupal\automatic_updates\Exception\UpdateException;
diff --git a/automatic_updates_extensions/tests/src/Kernel/Validator/UpdateReleaseValidatorTest.php b/automatic_updates_extensions/tests/src/Kernel/Validator/UpdateReleaseValidatorTest.php
index 80a3103093725bad91cc2542937a9c54d554f4be..c075b8e38917c05e76305a99486deac7b146cb2e 100644
--- a/automatic_updates_extensions/tests/src/Kernel/Validator/UpdateReleaseValidatorTest.php
+++ b/automatic_updates_extensions/tests/src/Kernel/Validator/UpdateReleaseValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates_extensions\Kernel\Validator;
 
 use Drupal\package_manager\LegacyVersionUtility;
diff --git a/package_manager/tests/fixtures/updated_module/1.1.0/src/PostApplySubscriber.php b/package_manager/tests/fixtures/updated_module/1.1.0/src/PostApplySubscriber.php
index 94092531f17cfb22fef647c41443c1c52058f3ef..83f1283d14e3edd4a6ea1dbcd12d1b69322bee36 100644
--- a/package_manager/tests/fixtures/updated_module/1.1.0/src/PostApplySubscriber.php
+++ b/package_manager/tests/fixtures/updated_module/1.1.0/src/PostApplySubscriber.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\updated_module;
 
 use Drupal\package_manager\Event\PostApplyEvent;
diff --git a/package_manager/tests/src/Build/PackageInstallTest.php b/package_manager/tests/src/Build/PackageInstallTest.php
index aa2167d32dd9a8c20263a6706959d2e110610634..814d73c7fffc54041f7ce5c2924e3e02312ea4d1 100644
--- a/package_manager/tests/src/Build/PackageInstallTest.php
+++ b/package_manager/tests/src/Build/PackageInstallTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Build;
 
 /**
diff --git a/package_manager/tests/src/Build/PackageUpdateTest.php b/package_manager/tests/src/Build/PackageUpdateTest.php
index 1547b238334f98b6c0d84abf47fd9d767386a3f9..44f88d60d660be0219fed18104badaf2e8540186 100644
--- a/package_manager/tests/src/Build/PackageUpdateTest.php
+++ b/package_manager/tests/src/Build/PackageUpdateTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Build;
 
 /**
diff --git a/package_manager/tests/src/Functional/FailureMarkerRequirementTest.php b/package_manager/tests/src/Functional/FailureMarkerRequirementTest.php
index 9da316ec671772b39b46cb4b9df1ca9a390ab2ce..1f5f59c3a2e10c244610f7f7f8181e5cd8f71363 100644
--- a/package_manager/tests/src/Functional/FailureMarkerRequirementTest.php
+++ b/package_manager/tests/src/Functional/FailureMarkerRequirementTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Functional;
 
 use Drupal\Core\StringTranslation\StringTranslationTrait;
diff --git a/package_manager/tests/src/Kernel/ComposerExecutableValidatorTest.php b/package_manager/tests/src/Kernel/ComposerExecutableValidatorTest.php
index 7e5a90ed6d5292a450ec7a5c6a46630b0ff30e95..ad1077234654c9a6b82c18e6155ba46bc123db8e 100644
--- a/package_manager/tests/src/Kernel/ComposerExecutableValidatorTest.php
+++ b/package_manager/tests/src/Kernel/ComposerExecutableValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
diff --git a/package_manager/tests/src/Kernel/ComposerPatchesValidatorTest.php b/package_manager/tests/src/Kernel/ComposerPatchesValidatorTest.php
index 142b716c42ee3308acf55df97f99e7cc21b91530..c9d854c2dbd8fb7d6cd2751ae038ab0153be2912 100644
--- a/package_manager/tests/src/Kernel/ComposerPatchesValidatorTest.php
+++ b/package_manager/tests/src/Kernel/ComposerPatchesValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Composer\Json\JsonFile;
diff --git a/package_manager/tests/src/Kernel/ComposerSettingsValidatorTest.php b/package_manager/tests/src/Kernel/ComposerSettingsValidatorTest.php
index 0ba92940de87ac6957db349348e0f6a37100f971..751a11563cebdb59d92f08155582cac2096ac55f 100644
--- a/package_manager/tests/src/Kernel/ComposerSettingsValidatorTest.php
+++ b/package_manager/tests/src/Kernel/ComposerSettingsValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Component\Serialization\Json;
diff --git a/package_manager/tests/src/Kernel/ComposerUtilityTest.php b/package_manager/tests/src/Kernel/ComposerUtilityTest.php
index 210eafd8a1698d7528e6624cc81294c6baa05b50..dbb649817bb12a3d184f6c4c482f0944a6f413b6 100644
--- a/package_manager/tests/src/Kernel/ComposerUtilityTest.php
+++ b/package_manager/tests/src/Kernel/ComposerUtilityTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\KernelTests\KernelTestBase;
diff --git a/package_manager/tests/src/Kernel/CorePackageManifestTest.php b/package_manager/tests/src/Kernel/CorePackageManifestTest.php
index ce501f2815f99297fdd10517c5c14fd42119017f..e5ededf42a3a90c5873ee4e6a00949a85f30fb6d 100644
--- a/package_manager/tests/src/Kernel/CorePackageManifestTest.php
+++ b/package_manager/tests/src/Kernel/CorePackageManifestTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Component\Serialization\Json;
diff --git a/package_manager/tests/src/Kernel/DiskSpaceValidatorTest.php b/package_manager/tests/src/Kernel/DiskSpaceValidatorTest.php
index 523b2d53df5bcbae1d92b73f1c18b7bbf18fb3fa..2d78ef27cfbbdeb70112ef8696d593f6bcd00b42 100644
--- a/package_manager/tests/src/Kernel/DiskSpaceValidatorTest.php
+++ b/package_manager/tests/src/Kernel/DiskSpaceValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreCreateEvent;
diff --git a/package_manager/tests/src/Kernel/DuplicateInfoFileValidatorTest.php b/package_manager/tests/src/Kernel/DuplicateInfoFileValidatorTest.php
index 15eddc5be3f09e012461112a7205abb410abb3ca..88e18a0df7b8507fd767060a10d5bb3379b16211 100644
--- a/package_manager/tests/src/Kernel/DuplicateInfoFileValidatorTest.php
+++ b/package_manager/tests/src/Kernel/DuplicateInfoFileValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Exception\StageValidationException;
diff --git a/package_manager/tests/src/Kernel/EnvironmentSupportValidatorTest.php b/package_manager/tests/src/Kernel/EnvironmentSupportValidatorTest.php
index 7ebb78ab26b0f5cbee5294dc17b9bc0b8d86a398..f20e5975433056ad525c67be8e9431da44b755d5 100644
--- a/package_manager/tests/src/Kernel/EnvironmentSupportValidatorTest.php
+++ b/package_manager/tests/src/Kernel/EnvironmentSupportValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreCreateEvent;
diff --git a/package_manager/tests/src/Kernel/ExecutableFinderTest.php b/package_manager/tests/src/Kernel/ExecutableFinderTest.php
index 82b92afc68debfe8ba6f9bb01945bcb9f11f316d..5a4c4818a59bca4c0f58a92e69e652014bc36081 100644
--- a/package_manager/tests/src/Kernel/ExecutableFinderTest.php
+++ b/package_manager/tests/src/Kernel/ExecutableFinderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
diff --git a/package_manager/tests/src/Kernel/FailureMarkerTest.php b/package_manager/tests/src/Kernel/FailureMarkerTest.php
index e00345c6c4b96b260e5e9cae06dad54066dbcd93..97708dabb02ca436827a100b8866b070c7b4039d 100644
--- a/package_manager/tests/src/Kernel/FailureMarkerTest.php
+++ b/package_manager/tests/src/Kernel/FailureMarkerTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Core\StringTranslation\StringTranslationTrait;
diff --git a/package_manager/tests/src/Kernel/FakeSiteFixtureTest.php b/package_manager/tests/src/Kernel/FakeSiteFixtureTest.php
index af8facb645bce50303e4fac57766a979107bbd0c..b5501c7fcc9a9a881484a376b33a203ce8510ab7 100644
--- a/package_manager/tests/src/Kernel/FakeSiteFixtureTest.php
+++ b/package_manager/tests/src/Kernel/FakeSiteFixtureTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\ComposerUtility;
diff --git a/package_manager/tests/src/Kernel/FileSyncerFactoryTest.php b/package_manager/tests/src/Kernel/FileSyncerFactoryTest.php
index e851c81cb5df6609da6562fb3a9e302a74d531d1..14e9e7da9eab102f6038bf2f07efb8ac453b15cb 100644
--- a/package_manager/tests/src/Kernel/FileSyncerFactoryTest.php
+++ b/package_manager/tests/src/Kernel/FileSyncerFactoryTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\KernelTests\KernelTestBase;
diff --git a/package_manager/tests/src/Kernel/FixtureUtilityTraitTest.php b/package_manager/tests/src/Kernel/FixtureUtilityTraitTest.php
index e95037eef0e725bda2df8cec0e8976cbc6e450e7..1d60428024d837f99bdebc0e4de6c7c681e57b70 100644
--- a/package_manager/tests/src/Kernel/FixtureUtilityTraitTest.php
+++ b/package_manager/tests/src/Kernel/FixtureUtilityTraitTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Tests\package_manager\Traits\FixtureUtilityTrait;
diff --git a/package_manager/tests/src/Kernel/LockFileValidatorTest.php b/package_manager/tests/src/Kernel/LockFileValidatorTest.php
index f4ff94bb13f23e4e2025861d80df9f80bad9cd30..4460d4ee3aeabe6c47e024f5fee6448bf18d5680 100644
--- a/package_manager/tests/src/Kernel/LockFileValidatorTest.php
+++ b/package_manager/tests/src/Kernel/LockFileValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreApplyEvent;
diff --git a/package_manager/tests/src/Kernel/MultisiteValidatorTest.php b/package_manager/tests/src/Kernel/MultisiteValidatorTest.php
index 5573fc7e15c553e13f0ab64090be6ba41c8732dc..7db26d1a852ef40d1e2eb00716aa13ec008d2c7c 100644
--- a/package_manager/tests/src/Kernel/MultisiteValidatorTest.php
+++ b/package_manager/tests/src/Kernel/MultisiteValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreCreateEvent;
diff --git a/package_manager/tests/src/Kernel/OverwriteExistingPackagesValidatorTest.php b/package_manager/tests/src/Kernel/OverwriteExistingPackagesValidatorTest.php
index b589d689983d50010b9f5df7590c2bf4389b23eb..142307555659c4fecde61db11735ed10119f6af2 100644
--- a/package_manager/tests/src/Kernel/OverwriteExistingPackagesValidatorTest.php
+++ b/package_manager/tests/src/Kernel/OverwriteExistingPackagesValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Exception\StageValidationException;
diff --git a/package_manager/tests/src/Kernel/PathExcluder/GitExcluderTest.php b/package_manager/tests/src/Kernel/PathExcluder/GitExcluderTest.php
index 0dc8a8c6ba54e6d599a72b7847cad83183892081..5aebbac9265b4a427c0c9ab61cfc4c0a025eed95 100644
--- a/package_manager/tests/src/Kernel/PathExcluder/GitExcluderTest.php
+++ b/package_manager/tests/src/Kernel/PathExcluder/GitExcluderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel\PathExcluder;
 
 use Drupal\Tests\package_manager\Kernel\PackageManagerKernelTestBase;
diff --git a/package_manager/tests/src/Kernel/PathExcluder/NodeModulesExcluderTest.php b/package_manager/tests/src/Kernel/PathExcluder/NodeModulesExcluderTest.php
index 2317185307c4045e6ee76c0c2bb325c79e9a9948..7b8bd2daf2f787e9cfe2d8767d01446b2cb632ce 100644
--- a/package_manager/tests/src/Kernel/PathExcluder/NodeModulesExcluderTest.php
+++ b/package_manager/tests/src/Kernel/PathExcluder/NodeModulesExcluderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel\PathExcluder;
 
 use Drupal\Tests\package_manager\Kernel\PackageManagerKernelTestBase;
diff --git a/package_manager/tests/src/Kernel/PathExcluder/SiteConfigurationExcluderTest.php b/package_manager/tests/src/Kernel/PathExcluder/SiteConfigurationExcluderTest.php
index 933b8f959f0ae7973e032e4cc19081a3d99da8e7..5826b46f0c25dccb99eefa7dbc93fd0d3814999c 100644
--- a/package_manager/tests/src/Kernel/PathExcluder/SiteConfigurationExcluderTest.php
+++ b/package_manager/tests/src/Kernel/PathExcluder/SiteConfigurationExcluderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel\PathExcluder;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
diff --git a/package_manager/tests/src/Kernel/PathExcluder/SiteFilesExcluderTest.php b/package_manager/tests/src/Kernel/PathExcluder/SiteFilesExcluderTest.php
index db680b143f98df5a97c0dff010d31d238e5a90fe..8f43f9f1437fc27a0df37eff33d443ae8a9218fe 100644
--- a/package_manager/tests/src/Kernel/PathExcluder/SiteFilesExcluderTest.php
+++ b/package_manager/tests/src/Kernel/PathExcluder/SiteFilesExcluderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel\PathExcluder;
 
 use Drupal\Tests\package_manager\Kernel\PackageManagerKernelTestBase;
diff --git a/package_manager/tests/src/Kernel/PathExcluder/SqliteDatabaseExcluderTest.php b/package_manager/tests/src/Kernel/PathExcluder/SqliteDatabaseExcluderTest.php
index 6dd086d8f274175e9dbfbe9362ff1685d4bfafea..386c028d2838267e9e6afc3e4d632ba6fbc59be0 100644
--- a/package_manager/tests/src/Kernel/PathExcluder/SqliteDatabaseExcluderTest.php
+++ b/package_manager/tests/src/Kernel/PathExcluder/SqliteDatabaseExcluderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel\PathExcluder;
 
 use Drupal\Core\Database\Connection;
diff --git a/package_manager/tests/src/Kernel/PathExcluder/TestSiteExcluderTest.php b/package_manager/tests/src/Kernel/PathExcluder/TestSiteExcluderTest.php
index 88e780f77d33eee63fcf6a77203aa1869809e564..9dec2fb94f2b33921d7412875c47c22787db8c14 100644
--- a/package_manager/tests/src/Kernel/PathExcluder/TestSiteExcluderTest.php
+++ b/package_manager/tests/src/Kernel/PathExcluder/TestSiteExcluderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel\PathExcluder;
 
 use Drupal\Tests\package_manager\Kernel\PackageManagerKernelTestBase;
diff --git a/package_manager/tests/src/Kernel/PathExcluder/VendorHardeningExcluderTest.php b/package_manager/tests/src/Kernel/PathExcluder/VendorHardeningExcluderTest.php
index 88a1202749c4c0d5b380997e2362b4cda271d3d9..ff81f4f246129a5a7a1e3e5d6beb74c45964e8d9 100644
--- a/package_manager/tests/src/Kernel/PathExcluder/VendorHardeningExcluderTest.php
+++ b/package_manager/tests/src/Kernel/PathExcluder/VendorHardeningExcluderTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel\PathExcluder;
 
 use Drupal\Tests\package_manager\Kernel\PackageManagerKernelTestBase;
diff --git a/package_manager/tests/src/Kernel/PendingUpdatesValidatorTest.php b/package_manager/tests/src/Kernel/PendingUpdatesValidatorTest.php
index 1308c2c17e188f125b71078608e75c49666c817b..ec565b328398df98db30503c29d00d9207589ccc 100644
--- a/package_manager/tests/src/Kernel/PendingUpdatesValidatorTest.php
+++ b/package_manager/tests/src/Kernel/PendingUpdatesValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreCreateEvent;
diff --git a/package_manager/tests/src/Kernel/ProjectInfoTest.php b/package_manager/tests/src/Kernel/ProjectInfoTest.php
index 8bb079875ee29da85006da0dcc5b487c2e28d9c5..b1c727d9a218d79268a4c45119758b77af759b4a 100644
--- a/package_manager/tests/src/Kernel/ProjectInfoTest.php
+++ b/package_manager/tests/src/Kernel/ProjectInfoTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Core\Logger\RfcLogLevel;
@@ -174,8 +176,8 @@ class ProjectInfoTest extends PackageManagerKernelTestBase {
     // the last checked time.
     $this->assertSame(123, $state->get('update.last_check'));
 
-    $this->assertTrue($logger->hasRecordThatContains('Invalid project format: Array', RfcLogLevel::ERROR));
-    $this->assertTrue($logger->hasRecordThatContains('[name] => AAA 8.x-5.x', RfcLogLevel::ERROR));
+    $this->assertTrue($logger->hasRecordThatContains('Invalid project format: Array', (string) RfcLogLevel::ERROR));
+    $this->assertTrue($logger->hasRecordThatContains('[name] => AAA 8.x-5.x', (string) RfcLogLevel::ERROR));
   }
 
   /**
diff --git a/package_manager/tests/src/Kernel/ServicesTest.php b/package_manager/tests/src/Kernel/ServicesTest.php
index bac20c469bbf2c543aad8ad86d89abe1bf039c09..33e3cc72874b3fe9ee2d38fdd46b3194b5929eef 100644
--- a/package_manager/tests/src/Kernel/ServicesTest.php
+++ b/package_manager/tests/src/Kernel/ServicesTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\KernelTests\KernelTestBase;
diff --git a/package_manager/tests/src/Kernel/SettingsValidatorTest.php b/package_manager/tests/src/Kernel/SettingsValidatorTest.php
index c737cad34d4f8a8d2c23ffde182493e0fc613ab3..49fd7f819b494e5b74befa9f3e7683adaa8a7bd0 100644
--- a/package_manager/tests/src/Kernel/SettingsValidatorTest.php
+++ b/package_manager/tests/src/Kernel/SettingsValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreCreateEvent;
diff --git a/package_manager/tests/src/Kernel/StageEventsTest.php b/package_manager/tests/src/Kernel/StageEventsTest.php
index 37a7d5aab3df745249fdf4d458b1822deb257c86..849727786c1d18b105400b5750cc3f3920cc4000 100644
--- a/package_manager/tests/src/Kernel/StageEventsTest.php
+++ b/package_manager/tests/src/Kernel/StageEventsTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
diff --git a/package_manager/tests/src/Kernel/StageOwnershipTest.php b/package_manager/tests/src/Kernel/StageOwnershipTest.php
index 28b084db0cc214499b323e53a7895f2a2d6913a8..3416d76fdb93e9793066e66cfd316610870811a7 100644
--- a/package_manager/tests/src/Kernel/StageOwnershipTest.php
+++ b/package_manager/tests/src/Kernel/StageOwnershipTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Core\File\FileSystem;
@@ -307,7 +309,7 @@ class StageOwnershipTest extends PackageManagerKernelTestBase {
         str_contains($record['context']['%path'], $dir)
       );
     };
-    $this->assertTrue($logger->hasRecordThatPasses($predicate, RfcLogLevel::ERROR));
+    $this->assertTrue($logger->hasRecordThatPasses($predicate, (string) RfcLogLevel::ERROR));
   }
 
 }
diff --git a/package_manager/tests/src/Kernel/StageTest.php b/package_manager/tests/src/Kernel/StageTest.php
index 0713fd419595f7c7dfa4ac6e2b6a153e521f96c1..66c7551f1f83d8e94866874a03e7615255f42e20 100644
--- a/package_manager/tests/src/Kernel/StageTest.php
+++ b/package_manager/tests/src/Kernel/StageTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Component\Datetime\Time;
@@ -415,8 +417,8 @@ class StageTest extends PackageManagerKernelTestBase {
       $this->container->get('tempstore.shared'),
       $this->container->get('datetime.time')
     );
-    $this->assertTrue($logger->hasRecord('Drupal\package_manager\Stage::TEMPSTORE_METADATA_KEY is overridden by ' . TestStageOverriddenConstants::class . '. This is deprecated because it can cause errors or other unexpected behavior. It is strongly recommended to stop overriding this constant. See https://www.drupal.org/node/3317450 for more information.', RfcLogLevel::ERROR));
-    $this->assertTrue($logger->hasRecord('Drupal\package_manager\Stage::TEMPSTORE_LOCK_KEY is overridden by ' . TestStageOverriddenConstants::class . '. This is deprecated because it can cause errors or other unexpected behavior. It is strongly recommended to stop overriding this constant. See https://www.drupal.org/node/3317450 for more information.', RfcLogLevel::ERROR));
+    $this->assertTrue($logger->hasRecord('Drupal\package_manager\Stage::TEMPSTORE_METADATA_KEY is overridden by ' . TestStageOverriddenConstants::class . '. This is deprecated because it can cause errors or other unexpected behavior. It is strongly recommended to stop overriding this constant. See https://www.drupal.org/node/3317450 for more information.', (string) RfcLogLevel::ERROR));
+    $this->assertTrue($logger->hasRecord('Drupal\package_manager\Stage::TEMPSTORE_LOCK_KEY is overridden by ' . TestStageOverriddenConstants::class . '. This is deprecated because it can cause errors or other unexpected behavior. It is strongly recommended to stop overriding this constant. See https://www.drupal.org/node/3317450 for more information.', (string) RfcLogLevel::ERROR));
   }
 
   /**
diff --git a/package_manager/tests/src/Kernel/StageValidationExceptionTest.php b/package_manager/tests/src/Kernel/StageValidationExceptionTest.php
index d905f232144d1cefdc2b401f3b5914a1d8073443..0b68618f253b7f22c3b53fb5f103cacf7b69922a 100644
--- a/package_manager/tests/src/Kernel/StageValidationExceptionTest.php
+++ b/package_manager/tests/src/Kernel/StageValidationExceptionTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreCreateEvent;
diff --git a/package_manager/tests/src/Kernel/StagedDBUpdateValidatorTest.php b/package_manager/tests/src/Kernel/StagedDBUpdateValidatorTest.php
index ede72c4874801ec934aa4c25444312c6ccf89969..dd65d36dbae0a5ee96a51a95b331d785ed9e5bd2 100644
--- a/package_manager/tests/src/Kernel/StagedDBUpdateValidatorTest.php
+++ b/package_manager/tests/src/Kernel/StagedDBUpdateValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\ValidationResult;
diff --git a/package_manager/tests/src/Kernel/StatusCheckTraitTest.php b/package_manager/tests/src/Kernel/StatusCheckTraitTest.php
index 5173eab284983f3f745ce291c073b80a7cc5bcd8..bc529e04df16a9ba80004a4a1892e38b758ec99f 100644
--- a/package_manager/tests/src/Kernel/StatusCheckTraitTest.php
+++ b/package_manager/tests/src/Kernel/StatusCheckTraitTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\CollectIgnoredPathsEvent;
diff --git a/package_manager/tests/src/Kernel/SupportedReleaseValidatorTest.php b/package_manager/tests/src/Kernel/SupportedReleaseValidatorTest.php
index 523241bf827901131b86ab0d94dcb3700f8a6bf2..539d753b289843cccbe49c826582b83ef3c3d526 100644
--- a/package_manager/tests/src/Kernel/SupportedReleaseValidatorTest.php
+++ b/package_manager/tests/src/Kernel/SupportedReleaseValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreApplyEvent;
diff --git a/package_manager/tests/src/Kernel/SymlinkValidatorTest.php b/package_manager/tests/src/Kernel/SymlinkValidatorTest.php
index 351af83ee2febb8f7a18899041d49a3c468a4496..ae5441a6d3b23ae1bcdac5b570e7e70e6558c7e6 100644
--- a/package_manager/tests/src/Kernel/SymlinkValidatorTest.php
+++ b/package_manager/tests/src/Kernel/SymlinkValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
diff --git a/package_manager/tests/src/Kernel/WritableFileSystemValidatorTest.php b/package_manager/tests/src/Kernel/WritableFileSystemValidatorTest.php
index bbef90d1dd23f5f55fa76132cc5bd154f302b937..ddc8c4876a522e69e51b33576afb95494d666a46 100644
--- a/package_manager/tests/src/Kernel/WritableFileSystemValidatorTest.php
+++ b/package_manager/tests/src/Kernel/WritableFileSystemValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\Event\PreCreateEvent;
diff --git a/package_manager/tests/src/Kernel/XdebugValidatorTest.php b/package_manager/tests/src/Kernel/XdebugValidatorTest.php
index 43ce87e044fa2c2e9242c770b9fc157b1682891b..b0e3b581f32ae6368ce24283c39b37e35f7aa230 100644
--- a/package_manager/tests/src/Kernel/XdebugValidatorTest.php
+++ b/package_manager/tests/src/Kernel/XdebugValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Kernel;
 
 use Drupal\package_manager\ValidationResult;
diff --git a/package_manager/tests/src/Unit/ComposerUtilityTest.php b/package_manager/tests/src/Unit/ComposerUtilityTest.php
index 54107de9d9dcbed186cf3f2dcc6aa6f53b9d2f40..7a004680bd175f92633848b0f0e5815699f6496d 100644
--- a/package_manager/tests/src/Unit/ComposerUtilityTest.php
+++ b/package_manager/tests/src/Unit/ComposerUtilityTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Unit;
 
 use Composer\Package\PackageInterface;
diff --git a/package_manager/tests/src/Unit/InstalledPackagesDataTest.php b/package_manager/tests/src/Unit/InstalledPackagesDataTest.php
index 566e11502fdc8b9a79bb0e5abda9a06d65c78850..c7957bf7e433c6e4a56462aee90f1fbe6500cea2 100644
--- a/package_manager/tests/src/Unit/InstalledPackagesDataTest.php
+++ b/package_manager/tests/src/Unit/InstalledPackagesDataTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Unit;
 
 use Composer\Autoload\ClassLoader;
diff --git a/package_manager/tests/src/Unit/PathLocatorTest.php b/package_manager/tests/src/Unit/PathLocatorTest.php
index 5bf9b0dd04bda1bc65373ab136a9e98a1ccd155d..4f4bc6ff92a002d64a2cdaf932f4d6f54087d949 100644
--- a/package_manager/tests/src/Unit/PathLocatorTest.php
+++ b/package_manager/tests/src/Unit/PathLocatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Unit;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
diff --git a/package_manager/tests/src/Unit/ProcessFactoryTest.php b/package_manager/tests/src/Unit/ProcessFactoryTest.php
index d0d646d756e6d4a614e03d98005a4fe6cb200fa3..a6d1c4fd076c87640400cc3e507f86e50ed469ba 100644
--- a/package_manager/tests/src/Unit/ProcessFactoryTest.php
+++ b/package_manager/tests/src/Unit/ProcessFactoryTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Unit;
 
 use Drupal\package_manager\ProcessFactory;
diff --git a/package_manager/tests/src/Unit/RequireEventTraitTest.php b/package_manager/tests/src/Unit/RequireEventTraitTest.php
index b28ecc53177ac6ad2e735f1f71d3acf067736126..f477749b85fa8366fbf146da3db77c4c8335a256 100644
--- a/package_manager/tests/src/Unit/RequireEventTraitTest.php
+++ b/package_manager/tests/src/Unit/RequireEventTraitTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Unit;
 
 use Drupal\Tests\UnitTestCase;
diff --git a/package_manager/tests/src/Unit/ValidationResultTest.php b/package_manager/tests/src/Unit/ValidationResultTest.php
index cdf0a6dfaa07e122d25c76fe3ffd819925aeba62..ccf221a8c372b0eb101cc2c25b01cd5bfd6f29fa 100644
--- a/package_manager/tests/src/Unit/ValidationResultTest.php
+++ b/package_manager/tests/src/Unit/ValidationResultTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\package_manager\Unit;
 
 use Drupal\package_manager\ValidationResult;
diff --git a/tests/modules/automatic_updates_test/src/Datetime/TestTime.php b/tests/modules/automatic_updates_test/src/Datetime/TestTime.php
index cea3504f4d594e947a142a3cd45fbacaa8af05b2..6048d6b65fd2bf2eacefc2bcc643fb0f597ab2de 100644
--- a/tests/modules/automatic_updates_test/src/Datetime/TestTime.php
+++ b/tests/modules/automatic_updates_test/src/Datetime/TestTime.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\automatic_updates_test\Datetime;
 
 use Drupal\Component\Datetime\Time;
diff --git a/tests/modules/automatic_updates_test/src/EventSubscriber/RequestTimeRecorder.php b/tests/modules/automatic_updates_test/src/EventSubscriber/RequestTimeRecorder.php
index 805c40f7465c83affd4b3c45a05a0397646b2994..4a1c1e82ea259acc54672518ca0bfa31de4f2656 100644
--- a/tests/modules/automatic_updates_test/src/EventSubscriber/RequestTimeRecorder.php
+++ b/tests/modules/automatic_updates_test/src/EventSubscriber/RequestTimeRecorder.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\automatic_updates_test\EventSubscriber;
 
 use Drupal\Component\Datetime\TimeInterface;
diff --git a/tests/modules/automatic_updates_test/src/EventSubscriber/TestSubscriber1.php b/tests/modules/automatic_updates_test/src/EventSubscriber/TestSubscriber1.php
index 428134123d268d04e6903b8f2c099c44a0ecdece..18f39c105f8b23773c65060665bcb0dba6f5b4cd 100644
--- a/tests/modules/automatic_updates_test/src/EventSubscriber/TestSubscriber1.php
+++ b/tests/modules/automatic_updates_test/src/EventSubscriber/TestSubscriber1.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\automatic_updates_test\EventSubscriber;
 
 use Drupal\package_manager_test_validation\EventSubscriber\TestSubscriber;
diff --git a/tests/modules/automatic_updates_test2/src/EventSubscriber/TestSubscriber2.php b/tests/modules/automatic_updates_test2/src/EventSubscriber/TestSubscriber2.php
index 907cbde3056862ab81eee819f3f15142448e8bb2..8a0ab811486f9836818e9910e86fe908da673e36 100644
--- a/tests/modules/automatic_updates_test2/src/EventSubscriber/TestSubscriber2.php
+++ b/tests/modules/automatic_updates_test2/src/EventSubscriber/TestSubscriber2.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\automatic_updates_test2\EventSubscriber;
 
 use Drupal\automatic_updates_test\EventSubscriber\TestSubscriber1;
diff --git a/tests/src/Build/CoreUpdateTest.php b/tests/src/Build/CoreUpdateTest.php
index 1355482a19909939782985bde86aecd168ea8d7d..97be7f9b610ebb75aa4f98b46a36c8026523b71d 100644
--- a/tests/src/Build/CoreUpdateTest.php
+++ b/tests/src/Build/CoreUpdateTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Build;
 
 use Drupal\Composer\Composer;
diff --git a/tests/src/Functional/AvailableUpdatesReportTest.php b/tests/src/Functional/AvailableUpdatesReportTest.php
index 0ab736335f0069b156d6c6216cb4479f0e6c893e..e11d6c8678fde8be0934770cd1df765ea0b287e1 100644
--- a/tests/src/Functional/AvailableUpdatesReportTest.php
+++ b/tests/src/Functional/AvailableUpdatesReportTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 use Drupal\Core\Url;
diff --git a/tests/src/Functional/DeprecatedRoutesTest.php b/tests/src/Functional/DeprecatedRoutesTest.php
index b52c55d95df2a31e10c8c8b784764809f7704906..ff89fd57f4fd078d451df45265489d5f47149b3e 100644
--- a/tests/src/Functional/DeprecatedRoutesTest.php
+++ b/tests/src/Functional/DeprecatedRoutesTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 use Drupal\Core\Url;
diff --git a/tests/src/Functional/HelpPageTest.php b/tests/src/Functional/HelpPageTest.php
index 0cf65bef43b9c4ed2d2ec29356cd5b69a301448a..bfe81a41b1fd1d43278992e3e9a791ab02e36db9 100644
--- a/tests/src/Functional/HelpPageTest.php
+++ b/tests/src/Functional/HelpPageTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 use Drupal\Tests\BrowserTestBase;
diff --git a/tests/src/Functional/StatusCheckTest.php b/tests/src/Functional/StatusCheckTest.php
index f3ce4e248779458cef5a5d7ba68db287a9ea8d14..84db352a40852c0424130a89591ce62b8378413f 100644
--- a/tests/src/Functional/StatusCheckTest.php
+++ b/tests/src/Functional/StatusCheckTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 use Behat\Mink\Element\NodeElement;
diff --git a/tests/src/Functional/UpdateLockTest.php b/tests/src/Functional/UpdateLockTest.php
index c68c25b2e291b0c62e315540eb77c0816aa9ee2c..720caba24013d5ace2e7a69d121a7c2e74feced6 100644
--- a/tests/src/Functional/UpdateLockTest.php
+++ b/tests/src/Functional/UpdateLockTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 use Drupal\package_manager_bypass\Stager;
diff --git a/tests/src/Functional/UpdatePathTest.php b/tests/src/Functional/UpdatePathTest.php
index a0e9f3b6aeed6efed62ce8f68c452be12d7abf75..2f5139acb8264557b37e4a64bd9cd66b6f44f5df 100644
--- a/tests/src/Functional/UpdatePathTest.php
+++ b/tests/src/Functional/UpdatePathTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 use Drupal\automatic_updates\StatusCheckMailer;
diff --git a/tests/src/Functional/UpdaterFormNoRecommendedReleaseMessageTest.php b/tests/src/Functional/UpdaterFormNoRecommendedReleaseMessageTest.php
index 6d8d7bbcc7e4b3439529dee68e28bf5f3ac33a47..d5990456919a028128e4fa02c09c52442dbca982 100644
--- a/tests/src/Functional/UpdaterFormNoRecommendedReleaseMessageTest.php
+++ b/tests/src/Functional/UpdaterFormNoRecommendedReleaseMessageTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 /**
diff --git a/tests/src/Functional/UpdaterFormTest.php b/tests/src/Functional/UpdaterFormTest.php
index 424325cb9ebcfb952579479f3c2cc7298fc9b1fc..f92049fa0ab079d10f50b722cfbd2be3407ae525 100644
--- a/tests/src/Functional/UpdaterFormTest.php
+++ b/tests/src/Functional/UpdaterFormTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Functional;
 
 use Drupal\automatic_updates_test\Datetime\TestTime;
diff --git a/tests/src/Kernel/CronUpdaterTest.php b/tests/src/Kernel/CronUpdaterTest.php
index 5cfa075ff7ea986068504ef9c0e6390703c1d39b..9078970cf6025f2003dce865e68e50256ca17954 100644
--- a/tests/src/Kernel/CronUpdaterTest.php
+++ b/tests/src/Kernel/CronUpdaterTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel;
 
 use Drupal\automatic_updates\CronUpdater;
@@ -51,7 +53,7 @@ class CronUpdaterTest extends AutomaticUpdatesKernelTestBase {
   /**
    * The test logger.
    *
-   * @var \Psr\Log\Test\TestLogger
+   * @var ColinODell\PsrTestLogger\TestLogger
    */
   private $logger;
 
@@ -156,7 +158,7 @@ class CronUpdaterTest extends AutomaticUpdatesKernelTestBase {
     $form = $form_builder->buildForm(UpdateSettingsForm::class, $form_state);
     // Ensure that the version ranges in the setting's description, which are
     // computed dynamically, look correct.
-    $this->assertStringContainsString('Automatic updates are only supported for 9.8.x versions of Drupal core. Drupal 9.8 will receive security updates until 9.10.0 is released.', $form['automatic_updates_cron']['#description']);
+    $this->assertStringContainsString('Automatic updates are only supported for 9.8.x versions of Drupal core. Drupal 9.8 will receive security updates until 9.10.0 is released.', (string) $form['automatic_updates_cron']['#description']);
     $form_state->setValue('automatic_updates_cron', $setting);
     $form_builder->submitForm(UpdateSettingsForm::class, $form_state);
 
@@ -301,7 +303,7 @@ class CronUpdaterTest extends AutomaticUpdatesKernelTestBase {
     $this->assertTrue($updater->isAvailable());
     $this->container->get('cron')->run();
 
-    $logged_by_updater = $this->logger->hasRecord($expected_log_message, RfcLogLevel::ERROR);
+    $logged_by_updater = $this->logger->hasRecord($expected_log_message, (string) RfcLogLevel::ERROR);
     // To check if the exception was logged by the main cron service, we need
     // to set up a special predicate, because exceptions logged by cron are
     // always formatted in a particular way that we don't control. But the
@@ -314,7 +316,7 @@ class CronUpdaterTest extends AutomaticUpdatesKernelTestBase {
       }
       return FALSE;
     };
-    $logged_by_cron = $cron_logger->hasRecordThatPasses($predicate, RfcLogLevel::ERROR);
+    $logged_by_cron = $cron_logger->hasRecordThatPasses($predicate, (string) RfcLogLevel::ERROR);
 
     // If a pre-destroy event flags a validation error, it's handled like any
     // other event (logged by the cron updater, but not the main cron service).
diff --git a/tests/src/Kernel/ReadinessCheckTest.php b/tests/src/Kernel/ReadinessCheckTest.php
index 24f23749bf7694fd168d4abf11659d7bbc59372f..c7d1cf2ec97cd75d445ef1b1648d87d9ab3eac31 100644
--- a/tests/src/Kernel/ReadinessCheckTest.php
+++ b/tests/src/Kernel/ReadinessCheckTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel;
 
 use Drupal\automatic_updates\Event\ReadinessCheckEvent;
diff --git a/tests/src/Kernel/ReleaseChooserTest.php b/tests/src/Kernel/ReleaseChooserTest.php
index 08340f1d69d25cc5ff50680ca356ac35868b7f8c..c6a720bf155f934293c918d24c37860f08527cb1 100644
--- a/tests/src/Kernel/ReleaseChooserTest.php
+++ b/tests/src/Kernel/ReleaseChooserTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel;
 
 use Drupal\Core\Extension\ExtensionVersion;
diff --git a/tests/src/Kernel/StatusCheck/CronFrequencyValidatorTest.php b/tests/src/Kernel/StatusCheck/CronFrequencyValidatorTest.php
index 693478a9b4a1635034c9f9d46944d6ab46cf1fb4..7009c957029e06f4c07e0163a3588a23937af4d2 100644
--- a/tests/src/Kernel/StatusCheck/CronFrequencyValidatorTest.php
+++ b/tests/src/Kernel/StatusCheck/CronFrequencyValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\automatic_updates\CronUpdater;
diff --git a/tests/src/Kernel/StatusCheck/CronServerValidatorTest.php b/tests/src/Kernel/StatusCheck/CronServerValidatorTest.php
index 13f525cc88a32e93f0addd5fd8f8ce07a1d9c2b0..fcac9f57e699264bdcea2630c1174dc09b08f57f 100644
--- a/tests/src/Kernel/StatusCheck/CronServerValidatorTest.php
+++ b/tests/src/Kernel/StatusCheck/CronServerValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\automatic_updates\CronUpdater;
@@ -111,10 +113,10 @@ class CronServerValidatorTest extends AutomaticUpdatesKernelTestBase {
       $this->container->get('cron')->run();
       if ($expected_results) {
         $error = new StageValidationException($expected_results);
-        $this->assertTrue($logger->hasRecord($error->getMessage(), RfcLogLevel::ERROR));
+        $this->assertTrue($logger->hasRecord($error->getMessage(), (string) RfcLogLevel::ERROR));
       }
       else {
-        $this->assertFalse($logger->hasRecords(RfcLogLevel::ERROR));
+        $this->assertFalse($logger->hasRecords((string) RfcLogLevel::ERROR));
       }
     }
   }
diff --git a/tests/src/Kernel/StatusCheck/ScaffoldFilePermissionsValidatorTest.php b/tests/src/Kernel/StatusCheck/ScaffoldFilePermissionsValidatorTest.php
index 8a7ec476970d7e8dd52883463fa4401b45901e3c..d5466717d4e0af20230860ad1a87c74e2ff1768a 100644
--- a/tests/src/Kernel/StatusCheck/ScaffoldFilePermissionsValidatorTest.php
+++ b/tests/src/Kernel/StatusCheck/ScaffoldFilePermissionsValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\package_manager\Exception\StageValidationException;
diff --git a/tests/src/Kernel/StatusCheck/StagedDatabaseUpdateValidatorTest.php b/tests/src/Kernel/StatusCheck/StagedDatabaseUpdateValidatorTest.php
index db2ced0f1bdc166351aa3cf07ac152807328b793..21a71143108ccfc3661e91dc12821781f8d52a0e 100644
--- a/tests/src/Kernel/StatusCheck/StagedDatabaseUpdateValidatorTest.php
+++ b/tests/src/Kernel/StatusCheck/StagedDatabaseUpdateValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\Core\Logger\RfcLogLevel;
@@ -92,7 +94,7 @@ class StagedDatabaseUpdateValidatorTest extends AutomaticUpdatesKernelTestBase {
    */
   public function testNoUpdates(): void {
     $this->container->get('cron')->run();
-    $this->assertFalse($this->logger->hasRecords(RfcLogLevel::ERROR));
+    $this->assertFalse($this->logger->hasRecords((string) RfcLogLevel::ERROR));
   }
 
   /**
@@ -115,7 +117,7 @@ class StagedDatabaseUpdateValidatorTest extends AutomaticUpdatesKernelTestBase {
 
     $this->container->get('cron')->run();
     $expected_message = "The update cannot proceed because possible database updates have been detected in the following extensions.\nSystem\nStark\n";
-    $this->assertTrue($this->logger->hasRecord($expected_message, RfcLogLevel::ERROR));
+    $this->assertTrue($this->logger->hasRecord($expected_message, (string) RfcLogLevel::ERROR));
   }
 
   /**
@@ -138,7 +140,7 @@ class StagedDatabaseUpdateValidatorTest extends AutomaticUpdatesKernelTestBase {
 
     $this->container->get('cron')->run();
     $expected_message = "The update cannot proceed because possible database updates have been detected in the following extensions.\nSystem\nStark\n";
-    $this->assertTrue($this->logger->hasRecord($expected_message, RfcLogLevel::ERROR));
+    $this->assertTrue($this->logger->hasRecord($expected_message, (string) RfcLogLevel::ERROR));
   }
 
   /**
@@ -163,7 +165,7 @@ class StagedDatabaseUpdateValidatorTest extends AutomaticUpdatesKernelTestBase {
 
     $this->container->get('cron')->run();
     $expected_message = "The update cannot proceed because possible database updates have been detected in the following extensions.\nSystem\nStark\n";
-    $this->assertTrue($this->logger->hasRecord($expected_message, RfcLogLevel::ERROR));
+    $this->assertTrue($this->logger->hasRecord($expected_message, (string) RfcLogLevel::ERROR));
   }
 
 }
diff --git a/tests/src/Kernel/StatusCheck/StagedProjectsValidatorTest.php b/tests/src/Kernel/StatusCheck/StagedProjectsValidatorTest.php
index fcad516f003b9b3d8ce442cb82ec77160557a0f0..8c648a0e80832ed423404cd0b044088ea641e40a 100644
--- a/tests/src/Kernel/StatusCheck/StagedProjectsValidatorTest.php
+++ b/tests/src/Kernel/StatusCheck/StagedProjectsValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\package_manager\Event\PreApplyEvent;
diff --git a/tests/src/Kernel/StatusCheck/StatusCheckFailureEmailTest.php b/tests/src/Kernel/StatusCheck/StatusCheckFailureEmailTest.php
index d69c1e6021732b86450ff39c3702ca63e9ee8285..b6e37b0173cc440f0d8b0c340fc61e7bea740432 100644
--- a/tests/src/Kernel/StatusCheck/StatusCheckFailureEmailTest.php
+++ b/tests/src/Kernel/StatusCheck/StatusCheckFailureEmailTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\automatic_updates\CronUpdater;
diff --git a/tests/src/Kernel/StatusCheck/StatusCheckerTest.php b/tests/src/Kernel/StatusCheck/StatusCheckerTest.php
index 566800e9bf35bbe1ab404d06cc31889f118d30ea..4199491448cca7df3b306b6ab7ecdfac4c5d6684 100644
--- a/tests/src/Kernel/StatusCheck/StatusCheckerTest.php
+++ b/tests/src/Kernel/StatusCheck/StatusCheckerTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\automatic_updates\CronUpdater;
diff --git a/tests/src/Kernel/StatusCheck/VersionPolicy/SupportedBranchInstalledTest.php b/tests/src/Kernel/StatusCheck/VersionPolicy/SupportedBranchInstalledTest.php
index 30fe297f8caec4f2f9c8432b975c6fffe11413f4..40aa0738d2b507d9800053a4b04faa1ec2a04173 100644
--- a/tests/src/Kernel/StatusCheck/VersionPolicy/SupportedBranchInstalledTest.php
+++ b/tests/src/Kernel/StatusCheck/VersionPolicy/SupportedBranchInstalledTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\SupportedBranchInstalled;
diff --git a/tests/src/Kernel/StatusCheck/VersionPolicyValidatorTest.php b/tests/src/Kernel/StatusCheck/VersionPolicyValidatorTest.php
index 515b0d75b6d9d96e709d0c1e8e8a6279b5ec3c55..827a30ffe6b9a0bae4bb656b63431b335df821cd 100644
--- a/tests/src/Kernel/StatusCheck/VersionPolicyValidatorTest.php
+++ b/tests/src/Kernel/StatusCheck/VersionPolicyValidatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\automatic_updates\CronUpdater;
diff --git a/tests/src/Kernel/StatusCheck/XdebugValidatorTest.php b/tests/src/Kernel/StatusCheck/XdebugValidatorTest.php
index 5327b101a6e8d4f21ca8258dc798d96ab3b2572c..a7006fe850dfd1e8a5e280a8bf87d9fcdea46af0 100644
--- a/tests/src/Kernel/StatusCheck/XdebugValidatorTest.php
+++ b/tests/src/Kernel/StatusCheck/XdebugValidatorTest.php
@@ -1,9 +1,12 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel\StatusCheck;
 
 use Drupal\automatic_updates\CronUpdater;
 use Drupal\Core\Logger\RfcLogLevel;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Drupal\package_manager\ValidationResult;
 use Drupal\Tests\automatic_updates\Kernel\AutomaticUpdatesKernelTestBase;
 use Drupal\Tests\package_manager\Traits\PackageManagerBypassTestTrait;
@@ -17,6 +20,7 @@ use ColinODell\PsrTestLogger\TestLogger;
 class XdebugValidatorTest extends AutomaticUpdatesKernelTestBase {
 
   use PackageManagerBypassTestTrait;
+  use StringTranslationTrait;
 
   /**
    * {@inheritdoc}
@@ -70,7 +74,7 @@ class XdebugValidatorTest extends AutomaticUpdatesKernelTestBase {
 
     $this->container->get('cron')->run();
     $this->assertUpdateStagedTimes(0);
-    $this->assertTrue($logger->hasRecordThatMatches("/$message/", RfcLogLevel::ERROR));
+    $this->assertTrue($logger->hasRecordThatMatches("/$message/", (string) RfcLogLevel::ERROR));
   }
 
 }
diff --git a/tests/src/Kernel/UpdaterTest.php b/tests/src/Kernel/UpdaterTest.php
index 2b365a60fd2bb5a76601ea7716f184b76638308c..ffa95dfef5332593742be42a465dcff6293a5093 100644
--- a/tests/src/Kernel/UpdaterTest.php
+++ b/tests/src/Kernel/UpdaterTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel;
 
 use Drupal\automatic_updates\Exception\UpdateException;
diff --git a/tests/src/Kernel/ValidationResultDisplayTraitTest.php b/tests/src/Kernel/ValidationResultDisplayTraitTest.php
index 319be3b8932302ec5829afe036559265024b7712..ee2b4bfdbe168538f97ea94adeaa883473de3b0d 100644
--- a/tests/src/Kernel/ValidationResultDisplayTraitTest.php
+++ b/tests/src/Kernel/ValidationResultDisplayTraitTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Kernel;
 
 use Drupal\automatic_updates\Validation\ValidationResultDisplayTrait;
diff --git a/tests/src/Unit/LegacyVersionUtilityTest.php b/tests/src/Unit/LegacyVersionUtilityTest.php
index 782602c8db98193b18672295cdd6c0f020f41e2d..b304dcafd195d46fe580b74de9a0cca1091004c1 100644
--- a/tests/src/Unit/LegacyVersionUtilityTest.php
+++ b/tests/src/Unit/LegacyVersionUtilityTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit;
 
 use Drupal\package_manager\LegacyVersionUtility;
diff --git a/tests/src/Unit/VersionPolicy/ForbidDevSnapshotTest.php b/tests/src/Unit/VersionPolicy/ForbidDevSnapshotTest.php
index 4ce40968b804d60e0ac3d92904ee32a57dbd62b8..a819d961c4235167c45d15b623a6f6cd7f3dcbdd 100644
--- a/tests/src/Unit/VersionPolicy/ForbidDevSnapshotTest.php
+++ b/tests/src/Unit/VersionPolicy/ForbidDevSnapshotTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\ForbidDevSnapshot;
diff --git a/tests/src/Unit/VersionPolicy/ForbidDowngradeTest.php b/tests/src/Unit/VersionPolicy/ForbidDowngradeTest.php
index 249cd81ee948ef43f5be9143e809b9030d2dd904..6de5d390875104a9fb978c0f76c59ab68bbfcb37 100644
--- a/tests/src/Unit/VersionPolicy/ForbidDowngradeTest.php
+++ b/tests/src/Unit/VersionPolicy/ForbidDowngradeTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\ForbidDowngrade;
diff --git a/tests/src/Unit/VersionPolicy/ForbidMinorUpdatesTest.php b/tests/src/Unit/VersionPolicy/ForbidMinorUpdatesTest.php
index 0e8e687ead2c818e2a54d250318bdef1a00526f6..9cba4f1d1536721b9cc6081b929ac266457141bb 100644
--- a/tests/src/Unit/VersionPolicy/ForbidMinorUpdatesTest.php
+++ b/tests/src/Unit/VersionPolicy/ForbidMinorUpdatesTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\ForbidMinorUpdates;
diff --git a/tests/src/Unit/VersionPolicy/MajorVersionMatchTest.php b/tests/src/Unit/VersionPolicy/MajorVersionMatchTest.php
index a24262ad6d65992ba44fd2654ac2a62866fdf4fd..db1f718b1b4ae4fb6c23338d7f296ef3e6675ae4 100644
--- a/tests/src/Unit/VersionPolicy/MajorVersionMatchTest.php
+++ b/tests/src/Unit/VersionPolicy/MajorVersionMatchTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\MajorVersionMatch;
diff --git a/tests/src/Unit/VersionPolicy/MinorUpdatesEnabledTest.php b/tests/src/Unit/VersionPolicy/MinorUpdatesEnabledTest.php
index 35442d46504e36ecf979137a670c6717bb16daf3..9059ef64a93365e5033bfd8926e42bb2545e9695 100644
--- a/tests/src/Unit/VersionPolicy/MinorUpdatesEnabledTest.php
+++ b/tests/src/Unit/VersionPolicy/MinorUpdatesEnabledTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\MinorUpdatesEnabled;
diff --git a/tests/src/Unit/VersionPolicy/StableReleaseInstalledTest.php b/tests/src/Unit/VersionPolicy/StableReleaseInstalledTest.php
index 2f85f791494fb062a5cac27d891254e77c032224..de34f4b194143d9118f7e9ea9bc3a0ce21f1072b 100644
--- a/tests/src/Unit/VersionPolicy/StableReleaseInstalledTest.php
+++ b/tests/src/Unit/VersionPolicy/StableReleaseInstalledTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\StableReleaseInstalled;
diff --git a/tests/src/Unit/VersionPolicy/TargetSecurityReleaseTest.php b/tests/src/Unit/VersionPolicy/TargetSecurityReleaseTest.php
index 1b7570ff06d4f23b5780b28b9be26cb63d2c57b0..97d047161c1ee60dc43e5001b616bfac803ca96e 100644
--- a/tests/src/Unit/VersionPolicy/TargetSecurityReleaseTest.php
+++ b/tests/src/Unit/VersionPolicy/TargetSecurityReleaseTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\TargetSecurityRelease;
diff --git a/tests/src/Unit/VersionPolicy/TargetVersionInstallableTest.php b/tests/src/Unit/VersionPolicy/TargetVersionInstallableTest.php
index 4bcb764a129d0eaf6034440691954d48597edda6..42fd26d56856759232cb0242d20c65034bb522dd 100644
--- a/tests/src/Unit/VersionPolicy/TargetVersionInstallableTest.php
+++ b/tests/src/Unit/VersionPolicy/TargetVersionInstallableTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\TargetVersionInstallable;
diff --git a/tests/src/Unit/VersionPolicy/TargetVersionStableTest.php b/tests/src/Unit/VersionPolicy/TargetVersionStableTest.php
index d42fcd03158f6654f6afc42bacf7c2a290166840..28de42037c93a09b0cd351dedd2f95a2d33433b0 100644
--- a/tests/src/Unit/VersionPolicy/TargetVersionStableTest.php
+++ b/tests/src/Unit/VersionPolicy/TargetVersionStableTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\automatic_updates\Unit\VersionPolicy;
 
 use Drupal\automatic_updates\Validator\VersionPolicy\TargetVersionStable;