7 files declare their use of JsonapiKernelTestBase in JSON:API 8

EntityResourceTest.php in tests/src/Kernel/Controller/EntityResourceTest.php

EntryPointTest.php in tests/src/Kernel/Controller/EntryPointTest.php

FieldResolverTest.php in tests/src/Kernel/Context/FieldResolverTest.php

FilterTest.php in tests/src/Kernel/Query/FilterTest.php

JsonApiDocumentTopLevelNormalizerTest.php in tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php

RelatedResourceTypesTest.php in tests/src/Kernel/ResourceType/RelatedResourceTypesTest.php

SerializerTest.php in tests/src/Kernel/Serializer/SerializerTest.php