feat: add priority field to letter variants and update related tests

Author: m-houston

packages/events/src/domain/letter-variant.ts

@@ -44,10 +44,10 @@ export const $LetterVariant = z
           "This is used to restrict a particular variant to a single supplier, " +
           "for example individual admail campaigns.",
       }),
-    priority: z.int().default(50).meta({
+    priority: z.int().min(1).max(100).default(50).meta({
       title: "Priority",
       description:
-        "Integer priority used to order letters for dispatch to suppliers. Defaults to 50 when omitted.",
+        "Integer priority used to order letters for dispatch to suppliers on a 1 to 100 scale, where lower values indicate higher priority. Defaults to 50 when omitted.",
     }),
     packSpecificationIds: z.array(idRef($PackSpecification)).nonempty().meta({
       title: "Pack Specifications",

packages/events/src/events/__tests__/letter-variant-events.test.ts

@@ -202,6 +202,60 @@ describe("LetterVariant Events", () => {
       expect(result.data?.data.priority).toBe(50);
     });
 
+    it("should validate priority at the highest boundary value", () => {
+      const eventAtHighestPriority = {
+        ...validProdEvent,
+        data: {
+          ...validProdEvent.data,
+          priority: 1,
+        },
+      };
+
+      const result = $LetterVariantEvent.safeParse(eventAtHighestPriority);
+      expect(result.success).toBe(true);
+      expect(result.data?.data.priority).toBe(1);
+    });
+
+    it("should validate priority at the lowest boundary value", () => {
+      const eventAtLowestPriority = {
+        ...validProdEvent,
+        data: {
+          ...validProdEvent.data,
+          priority: 100,
+        },
+      };
+
+      const result = $LetterVariantEvent.safeParse(eventAtLowestPriority);
+      expect(result.success).toBe(true);
+      expect(result.data?.data.priority).toBe(100);
+    });
+
+    it("should reject priority lower than the allowed range", () => {
+      const invalidEvent = {
+        ...validProdEvent,
+        data: {
+          ...validProdEvent.data,
+          priority: 0,
+        },
+      };
+
+      const result = $LetterVariantEvent.safeParse(invalidEvent);
+      expect(result.success).toBe(false);
+    });
+
+    it("should reject priority higher than the allowed range", () => {
+      const invalidEvent = {
+        ...validProdEvent,
+        data: {
+          ...validProdEvent.data,
+          priority: 101,
+        },
+      };
+
+      const result = $LetterVariantEvent.safeParse(invalidEvent);
+      expect(result.success).toBe(false);
+    });
+
     it("should validate specialised schema enforces PROD status", () => {
       const prodSchema = letterVariantEvents["letter-variant.prod"];
 

packages/file-store/src/__tests__/config-store-validator.test.ts

@@ -14,7 +14,7 @@ jest.mock("@nhsdigital/nhs-notify-event-schemas-supplier-config", () => {
     }),
     $LetterVariant: z.object({
       id: z.string(),
-      priority: z.number().int().default(50),
+      priority: z.number().int().min(1).max(100).default(50),
       packSpecificationIds: z.array(z.string()).min(1),
     }),
     $PackSpecification: z.object({
@@ -165,6 +165,29 @@ describe("validateConfigStore", () => {
     expect(result.issues[0]?.path).toEqual(["packSpecificationIds", 0]);
   });
 
+  it("should reject letter variant priority values outside the allowed range", () => {
+    const result = validateConfigStore({
+      rootPath: mockRootPath,
+      records: [
+        makeRecord("letter-variant", "lv-1", {
+          id: "lv-1",
+          priority: 101,
+          packSpecificationIds: ["pack-spec-1"],
+        }),
+      ],
+    });
+
+    expect(result.ok).toBe(false);
+    expect(result.issues).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          entity: "letter-variant",
+          path: ["priority"],
+        }),
+      ]),
+    );
+  });
+
   it("should return ok=true with no issues when all records are valid", () => {
     const result = validateConfigStore({
       rootPath: mockRootPath,