Make the display value and stored value explicit
A state picker may display a full region name while an application stores a two-letter code. Test those as separate values connected by an explicit mapping. A visible label of California should not be saved as a translated label, a numeric option index, or a previously selected state. The same principle applies when your interface language changes but the receiving system still expects a stable code.
Use a small set of meaningful comparisons
You do not need a long list of capitals to verify an address selector. Start with code and label pairs that expose likely mistakes: California and CA, Delaware and DE, New York and NY, Washington and WA, and District of Columbia and DC. Washington state and the District of Columbia are distinct region choices. Check your own product’s scope before assuming that every region offered by another service is available here.
- Select by visible name and inspect the value exported by your application.
- Restore a saved code and check that the correct label is displayed.
- Change interface language and retain the same selected region.
- Try an unknown code and require a defined error or empty state.
Include the District of Columbia deliberately
This tool’s US postal dataset covers fifty states plus the District of Columbia, for fifty-one region entries. That count is a dataset scope statement, not a claim that DC is a state. Tests should preserve the distinction in labels and descriptions. Do not use the number of entries as proof of coverage for territories, military addressing, or every special address format your product might need.
Test what happens after a region changes
Choose one state and city, generate a record, then select a different state. Verify that incompatible locality selections are cleared or explicitly revalidated before the next action. If your application caches generated results, make the relationship between displayed data and active filters clear. Finally, export a reviewed sample and check that region fields match the visible result. Treat the export’s actual field names as the contract; JSON and CSV need not expose identical shapes.