Found these problems and fixed them (related to tests in the patch):

Added more unit tests (original version created by Erik).

Tested all units, additional bugs found in the In-Commerce module.

I've noticed, that the same issue happens also with coupi and api units of the In-Commerce. Please expand the Differential Revision code/test plan to cover them as well.

Partially tested (done testing for Core module part).

1. Languages.

1.1. Broken In-Portal clean install due error in lang prefix, preventing language record creation, required in normal installation process.
1.2. Due specific option_sql configuration for PackName and LocalName fields, possible add only record with values, that already exists. So, when no records in Languages table - can't add first language record.

2. Categories - works well in admin interface, but problematic to add through object, because of Priority field options, that are populated only in OnPreSaveCreated event hook.
3. Change logs - sometimes can't create through object same as languages, due specific Prefix and MasterPrefix field options_sql configuration. But in system records are created by direct SQL, so this not a problem. maybe.
4. Users - can't create and update records with US State, because state options are populated too late - after SetFieldsFromHash already set error to the State field.

In D529#10861, @erik wrote:

I do not understand relation between test plan and proposed automation logic.

1. As I understand from test plan, not only required fields should be tested, but fields with specific formatter.
2. As I understand from test plan, should test not only create, but also update.
3. Each unit may be specific, may have dependencies to another units, so proposed automation logic seems is not helpful.

I do not understand relation between test plan and proposed automation logic.

In D529#10843, @erik wrote:

Made partial testing. In the u and addr units, on State field Detected unknown_option validation error. As discussed in Zoom, started writing code for automated unit test to check create/update all units with kOptionsFormatter.

Made partial testing. In the u and addr units, on State field Detected unknown_option validation error. As discussed in Zoom, started writing code for automated unit test to check create/update all units with kOptionsFormatter.

In D531#10825, @erik wrote:

Part 3 - "confirm that the Select Module Root Section system setting value was properly saved" - It's not properly saved. After "Save" button pressed, page reloads and returns old Home → Products value.

Part 3 - "confirm that the Select Module Root Section system setting value was properly saved" - It's not properly saved. After "Save" button pressed, page reloads and returns old Home → Products value.

Corrected the length of the UserSessionLogs.IP during clean install.

In D528#10766, @erik wrote:

After clean install:

2.1 kUtilTest::testNetMatch test, 2 tests failed

name: www.in-portal.org; actual: 69.27.40.110
This test printed output: name: www.in-portal.org; actual: 69.27.40.110

name: www.yahoo.com; actual: 188.125.94.204
This test printed output: name: www.yahoo.com; actual: 188.125.94.204

Added missing phrase.

After clean install:

Use www.in-portal.org domain for testing instead of www.google.com to avoid Anycast DNS issues (random IP address returned on each DNS query).

Added missing la_fld_ExtraHTTPHeaders phrase.

All test plan passed.

I've added # (new) apply the patch from the D524, unless it's already committed line, that should fix the problem. Please retest.

2.2 - this part of test plan is excessive

2.2 - this part of test plan is excessive
2.3 - Failed all front-end tests. Always shown Oops, something went wrong text, not 404 page. Always System Log IS created about incident