fflib_SObjectSelectorTest.cls Tests Failing in Multicurrency scratch org

[parsam97]

Describe the bug
All tests that expect CurrencyIsoCode to appear for CaseComment are failing. Commenting these lines
expectedSelectFields.add('currencyisocode');
...enable the tests in that class to pass.

CaseComment does not have a CurrencyIsoCode field as far as I'm aware. So I'm wondering why these tests are specifically asserting for something directly against that.

To Reproduce

With the packages installed on a scratch org with multicurrency enabled (using the same scratch org definition file as provided on fflib-apex-common repo), run tests in fflib_SObjectSelectorTest.cls.

Expected behavior
Tests in multicurrency org to pass.

Screenshots and text of error observed
For instance:

fflib_SObjectSelectorTest.toSOQL_When_SystemModePolymorphicSelect_Expect_RelatedType  fflib_SObjectSelector  Fail     43%      System.AssertException: Assertion Failed: Expected: SELECT id, commentbody, currencyisocode, parent.ownerid, parent.id, parent.currencyisocode, parent.owner.userroleid, parent.owner.id, parent.owner.currencyisocode FROM CaseComment WITH SYSTEM_MODE ORDER BY CreatedDate ASC NULLS FIRST , Actual: SELECT id, commentbody, parent.ownerid, parent.id, parent.currencyisocode, parent.owner.userroleid, parent.owner.id, parent.owner.currencyisocode FROM CaseComment WITH SYSTEM_MODE ORDER BY CreatedDate ASC NULLS FIRST

Version
Yes, I've cloned the repo today and started playing around with it and discovered that tests aren't passing in multicurrency org.

[parsam97]

This method:
toSOQL_When_GreatGreatGrandchildRelationships_Expect_WelformedSOQL
has also not taken multicurrency into account with the fields it expects in the assertion.

Hacky solution but it passes now.

String currencyIsoCodeFieldLast = '';
String currencyIsoCodeFieldNonLast = '';
if (UserInfo.isMultiCurrencyOrganization()) {
	currencyIsoCodeFieldLast = ', currencyisocode';
	currencyIsoCodeFieldNonLast = 'currencyisocode, ';
}

String expected
		= 'SELECT name, id, annualrevenue, accountnumber, ' + currencyIsoCodeFieldNonLast
		+   '(SELECT id, contractnumber, ' + currencyIsoCodeFieldNonLast
		+     '(SELECT name, id, amount, closedate, ' + currencyIsoCodeFieldNonLast
		+       '(SELECT id, name, ' + currencyIsoCodeFieldNonLast
		+         '(SELECT id, subject' + currencyIsoCodeFieldLast + ' FROM Tasks ORDER BY Subject ASC NULLS FIRST )  '
		+       'FROM ListEmails ORDER BY Name ASC NULLS FIRST )  '
		+     'FROM Opportunities ORDER BY Name ASC NULLS FIRST )  '
		+   'FROM Contracts ORDER BY ContractNumber ASC NULLS FIRST )  '
		+ 'FROM Account WITH USER_MODE ORDER BY Name ASC NULLS FIRST ';