fix issue and add consolidation

apps/edr-freight-api/src/modules/train-scheduling/utils/wagon-plan.util.spec.ts

@@ -14,6 +14,7 @@ import {
   sumWagonsRequired,
   validate20ftContainerRules,
   validateContainerPlacements,
+  validateWagonCargoExclusivity,
 } from './wagon-plan.util';
 
 const nw5: WagonType = {
@@ -222,6 +223,85 @@ describe('wagon-plan.util', () => {
     expect(plan[0]?.slotLoadType).toBe('BULK');
     expect(buildBulkWagonPlan([bulkBooking], cw3)).toHaveLength(1);
   });
+
+  it('never pools two bulk bookings on one wagon', () => {
+    // 5T + 40T both fit a single 60T CW3 by tonnage — but a wagon with bulk
+    // takes that one load only, so each booking gets its own wagon.
+    const small = {
+      id: 'bulk-5',
+      reference: 'bulk-5',
+      freightType: 'BULK',
+      cargoTotalWeightVgm: 5,
+      bookingContainers: [],
+    } as unknown as Booking;
+    const other = {
+      id: 'bulk-40',
+      reference: 'bulk-40',
+      freightType: 'BULK',
+      cargoTotalWeightVgm: 40,
+      bookingContainers: [],
+    } as unknown as Booking;
+    const plan = buildBulkWagonPlan([small, other], cw3);
+    expect(plan).toHaveLength(2);
+    for (const slot of plan) {
+      expect(slot.allocations).toHaveLength(1);
+    }
+    expect(plan[0]?.allocations[0]?.bookingId).toBe('bulk-5');
+    expect(plan[1]?.allocations[0]?.bookingId).toBe('bulk-40');
+    expect(validateWagonCargoExclusivity(plan)).toEqual([]);
+  });
+
+  it('a multi-wagon bulk booking still spreads over its own wagons', () => {
+    const big = {
+      id: 'bulk-130',
+      reference: 'bulk-130',
+      freightType: 'BULK',
+      cargoTotalWeightVgm: 130,
+      bookingContainers: [],
+    } as unknown as Booking;
+    const plan = buildBulkWagonPlan([big], cw3);
+    expect(plan).toHaveLength(3);
+    expect(plan.map((s) => s.allocations[0]?.allocatedWeightTons)).toEqual([60, 60, 10]);
+  });
+
+  it('flags a wagon mixing bulk with anything else', () => {
+    const bulkAlloc = {
+      bookingId: 'b',
+      bookingReference: 'b',
+      allocatedWeightTons: 5,
+      loadType: AllocationLoadType.Bulk,
+    };
+    const containerAlloc = {
+      bookingId: 'c',
+      bookingReference: 'c',
+      allocatedWeightTons: 25,
+      loadType: AllocationLoadType.Container,
+    };
+    const slot = (allocations: (typeof bulkAlloc)[]) => ({
+      sequenceNo: 1,
+      wagonTypeId: cw3.id,
+      wagonTypeCode: cw3.code,
+      capacityTons: 60,
+      lengthMeters: 14,
+      tareWeightTons: 24,
+      assignedWeightTons: 0,
+      allocations,
+    });
+    // bulk + container on one wagon
+    expect(validateWagonCargoExclusivity([slot([bulkAlloc, containerAlloc])]))
+      .toHaveLength(1);
+    // bulk + bulk on one wagon
+    expect(
+      validateWagonCargoExclusivity([slot([bulkAlloc, { ...bulkAlloc, bookingId: 'b2' }])]),
+    ).toHaveLength(1);
+    // bulk alone, and containers sharing, are fine
+    expect(validateWagonCargoExclusivity([slot([bulkAlloc])])).toEqual([]);
+    expect(
+      validateWagonCargoExclusivity([
+        slot([containerAlloc, { ...containerAlloc, bookingId: 'c2' }]),
+      ]),
+    ).toEqual([]);
+  });
 });
 
 describe('containerWagonsForLines — TEU-aware, ceil booking total once', () => {