# 1. Goal
Show all shipments in one list. The shipments come from two tables: road shipments
and rail shipments. The list must also show the transport mode as text. A report
and an OData service will read the list, so the union must be in the database, in
a CDS view.

# 2. Open questions
None.

# 3. Context
- Table {{P}}ROAD (road shipments), package $TMP. Key: SHIP_ID (CHAR 10).
  Fields: CUST (CHAR 10, customer), KG (DEC 15,3, weight), COST (DEC 15,2).
- Table {{P}}RAIL (rail shipments), package $TMP. Key: SHIP_ID (CHAR 10).
  Fields: CUSTOMER (CHAR 10, customer), WEIGHT (DEC 15,3, weight),
  FEE (DEC 15,2).
- The two tables use different column names for the same content.
- Both tables have data. A seed class fills them.

# 4. Contract
- Create the CDS view entity {{P}}I_SHIPMENT in package $TMP.
- The elements have these names: SHIP_ID, CUSTOMER, SHIP_MODE, WEIGHT, COST.
- No authorization check (#NOT_REQUIRED).

# 5. Business rules
1. The view is the union of {{P}}ROAD and {{P}}RAIL. Each row of {{P}}ROAD gives
   one row of the view, and each row of {{P}}RAIL gives one row of the view.
2. SHIP_MODE is the literal 'ROAD' for a row that comes from {{P}}ROAD.
   SHIP_MODE is the literal 'RAIL' for a row that comes from {{P}}RAIL.
3. CUSTOMER is CUST for a road shipment and CUSTOMER for a rail shipment.
4. WEIGHT is KG for a road shipment and WEIGHT for a rail shipment.
5. COST is COST for a road shipment and FEE for a rail shipment.
6. A shipment with a weight that is not positive (0 or less) is not in the view.

# 6. Constraints
- Release target: 7.58.
- Coding standards: Clean ABAP.
- Out of scope: do not change {{P}}ROAD and {{P}}RAIL.

# 7. Acceptance
- The view is active and has no syntax error.
- The hidden tests pass.
- Write ABAP Unit tests with CL_CDS_TEST_ENVIRONMENT in a global test class.