Add independent part management and catalogue suggestions (TC-19 to TC-25)

Summary

• Added independent part creation from the Station Inventory page
• Added part name, unit, station, and initial-quantity fields
• Allowed an initial inventory quantity of zero
• Allowed an existing part to be assigned to another station
• Added case-insensitive part-name matching to prevent duplicate master records
• Preserved automatic part creation when a new part name is entered in a production step
• Added automatic zero-quantity station inventory when a job step introduces a part
• Added searchable part suggestions to the production-step form
• Preserved existing station stock when an existing catalogue part is selected

Test Cases

TC-19 — Create part with zero quantity

An administrator can create a part directly from Station Inventory, assign it to any station, select its unit, and set its initial quantity to zero.

TC-20 — Assign existing part to another station

An existing part can be assigned to another station with an independent quantity. Name and unit matching is case-insensitive, and no duplicate part master record is created.

TC-21 — Protect existing station inventory

Attempting to add the same part to the same station again is rejected. Existing inventory quantities are not overwritten.

TC-22 — Reuse catalogue part in a job step

When a job-step part name matches an existing catalogue part, including differences in capitalization or surrounding spaces, the existing part is reused. A zero-stock station record is created only when the selected station does not already have one.

TC-23 — Create new part from a job step

When the entered job-step part name does not match the catalogue, a new part is created with the default unit pcs. Its selected station receives an initial inventory quantity of zero.

TC-24 — Display searchable part suggestions

The production-step part field displays catalogue suggestions while still allowing the administrator to enter a completely new part name.

TC-25 — Reject negative initial quantity

A negative initial station quantity is rejected without creating a part or inventory record.

Verification

Automated test suite:

python -m pytest -v

Result:

46 passed

Manual verification confirmed:

• A new part was created directly at Station 2 with quantity zero
• A part using unit kg was created at Station 4
• An existing part was assigned to Station 5 without creating a duplicate master record
• Existing parts appeared as job-step suggestions
• Selecting an existing part did not overwrite station stock
• Entering a new job-step part created it with zero station inventory
• Activating a job with insufficient stock created the expected warehouse transfer requests