feat: add pricing provider boundary

apps/api/tests/application/pricing-provider.test.js

@@ -0,0 +1,22 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import { createPricingProvider, createPricingProviderRegistry } from '../../src/modules/pricing/providers/pricing-provider.js';
+
+test('registers pricing providers behind a validated adapter contract', async () => {
+  const provider = createPricingProvider({
+    id: 'example',
+    async observe() { return [{ priceMinor: 2500, sourceIdentifier: 'example-1' }]; },
+  });
+  const registry = createPricingProviderRegistry([provider]);
+
+  assert.equal(registry.get('example'), provider);
+  assert.deepEqual(await registry.get('example').observe({}), [{ priceMinor: 2500, sourceIdentifier: 'example-1' }]);
+  assert.deepEqual(registry.list(), [provider]);
+});
+
+test('rejects malformed provider adapters and responses', async () => {
+  assert.throws(() => createPricingProvider({ id: 'broken' }), /observe function is required/);
+  const provider = createPricingProvider({ id: 'broken', async observe() { return null; } });
+  await assert.rejects(() => provider.observe({}), /must return an observation array/);
+});

apps/api/tests/application/pricing-service.test.js

@@ -34,4 +34,16 @@ test('requires a reason for an audited market-value override', async () => {
     () => service.override({ sellerId: 'seller-1', actorUserId: 'user-1', inventoryItemId: 'inventory-1', valueMinor: 2000, reason: 'x' }),
     (error) => error.code === 'OVERRIDE_REASON_REQUIRED' && error.statusCode === 400,
   );
+});
+
+test('fails clearly when a requested pricing provider is unavailable', async () => {
+  const service = createPricingService({
+    pricingRepository: {},
+    pricingProviderRegistry: { get() { return null; } },
+  });
+
+  await assert.rejects(
+    () => service.refresh({ sellerId: 'seller-1', inventoryItemId: 'inventory-1', providerId: 'missing' }),
+    (error) => error.code === 'PRICING_PROVIDER_UNAVAILABLE' && error.statusCode === 503,
+  );
 });