FileFieldRevisionTestCase::testRevisions in core/modules/file/tests/file.test

Tests creating multiple revisions of a node and managing attached files.

FileFieldValidateTestCase::testFileExtension in core/modules/file/tests/file.test

Tests file extension checking.

FileFieldValidateTestCase::testFileMaxSize in core/modules/file/tests/file.test

Tests the max file size validator.

FileFieldValidateTestCase::testRequired in core/modules/file/tests/file.test

Tests the required property on file fields.