Feature faker seed

docs/src/pages/guides/msw.md

@@ -156,3 +156,30 @@ import { setupServer } from 'msw/node';
 const server = setupServer();
 server.use(...getPetsMock());
 ```
+
+---
+
+### Deterministic Mock Data with `faker.seed`
+
+By default, faker generates random mock data on each run. You can repeat the same output with the `seed` option in your mock configuration. This will inject a `faker.seed(...)` call into your generated mock files, ensuring deterministic output.
+
+#### Configuration Example
+
+```typescript
+import { defineConfig } from 'orval';
+
+export default defineConfig({
+  petstore: {
+    output: {
+      target: './src/petstore.ts',
+      mock: {
+        type: 'msw',
+        seed: 12345, // Set a deterministic seed
+      },
+    },
+    input: {
+      target: './petstore.yaml',
+    },
+  },
+});
+```

packages/core/src/types.ts

@@ -320,6 +320,8 @@ export type GlobalMockOptions = {
   baseUrl?: string;
   // This is used to set the locale of the faker library
   locale?: keyof typeof allLocales;
+  // This is used to seed the faker library for deterministic output
+  seed?: number | number[];
   indexMockFiles?: boolean;
 };
 

packages/mock/src/msw/index.test.ts

@@ -0,0 +1,105 @@
+import { describe, it, expect, vi } from 'vitest';
+import { generateMSWImports } from './index';
+import { OutputMockType } from '@orval/core';
+
+// Mock the generateDependencyImports function
+vi.mock('@orval/core', async () => {
+  const actual =
+    await vi.importActual<typeof import('@orval/core')>('@orval/core');
+  return {
+    ...actual,
+    generateDependencyImports: vi.fn(
+      () =>
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";',
+    ),
+  };
+});
+
+describe('generateMSWImports', () => {
+  const mockParams = {
+    implementation: 'mock-implementation',
+    imports: [],
+    specsName: { test: 'test-specs' },
+    hasSchemaDir: false,
+    isAllowSyntheticDefaultImports: false,
+  };
+
+  describe('faker seed functionality', () => {
+    it('should return import block without seed when seed is undefined', () => {
+      const result = generateMSWImports({
+        ...mockParams,
+        options: { type: OutputMockType.MSW },
+      });
+
+      expect(result).toBe(
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";',
+      );
+    });
+
+    it('should add faker.seed call with numeric seed', () => {
+      const result = generateMSWImports({
+        ...mockParams,
+        options: { type: OutputMockType.MSW, seed: 12345 },
+      });
+
+      expect(result).toBe(
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";\nfaker.seed(12345);\n\n',
+      );
+    });
+
+    it('should add faker.seed call with array seed', () => {
+      const result = generateMSWImports({
+        ...mockParams,
+        options: { type: OutputMockType.MSW, seed: [123, 456, 789] },
+      });
+
+      expect(result).toBe(
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";\nfaker.seed([123, 456, 789]);\n\n',
+      );
+    });
+
+    it('should add faker.seed call with single element array', () => {
+      const result = generateMSWImports({
+        ...mockParams,
+        options: { type: OutputMockType.MSW, seed: [42] },
+      });
+
+      expect(result).toBe(
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";\nfaker.seed([42]);\n\n',
+      );
+    });
+
+    it('should add faker.seed call with zero seed', () => {
+      const result = generateMSWImports({
+        ...mockParams,
+        options: { type: OutputMockType.MSW, seed: 0 },
+      });
+
+      expect(result).toBe(
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";\nfaker.seed(0);\n\n',
+      );
+    });
+
+    it('should not add seed when array is empty', () => {
+      const result = generateMSWImports({
+        ...mockParams,
+        options: { type: OutputMockType.MSW, seed: [] },
+      });
+
+      expect(result).toBe(
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";',
+      );
+    });
+
+    it('should not add seed when options is undefined', () => {
+      const result = generateMSWImports({
+        ...mockParams,
+        options: undefined,
+      });
+
+      expect(result).toBe(
+        'import { http, HttpResponse } from "msw";\nimport { faker } from "@faker-js/faker";',
+      );
+    });
+  });
+});

packages/mock/src/msw/index.ts

@@ -53,13 +53,19 @@ export const generateMSWImports: GenerateMockImports = ({
   isAllowSyntheticDefaultImports,
   options,
 }) => {
-  return generateDependencyImports(
+  const importBlock = generateDependencyImports(
     implementation,
     [...getMSWDependencies(options), ...imports],
     specsName,
     hasSchemaDir,
     isAllowSyntheticDefaultImports,
   );
+
+  const seed = options?.seed;
+  if (seed !== undefined && !(Array.isArray(seed) && seed.length === 0)) {
+    return `${importBlock}\nfaker.seed(${Array.isArray(seed) ? `[${seed.join(', ')}]` : seed});\n\n`;
+  }
+  return importBlock;
 };
 
 const generateDefinition = (

tests/configs/mock.config.ts

@@ -89,7 +89,9 @@ export default defineConfig({
     output: {
       target: '../generated/mock/petstore-tags-split/endpoints.ts',
       schemas: '../generated/mock/petstore-tags-split/model',
-      mock: true,
+      mock: {
+        seed: 1234,
+      },
       mode: 'tags-split',
       client: 'axios',
     },
@@ -101,7 +103,9 @@ export default defineConfig({
     output: {
       target: '../generated/mock/split/endpoints.ts',
       schemas: '../generated/mock/split/model',
-      mock: true,
+      mock: {
+        seed: [42, 101],
+      },
       mode: 'split',
       client: 'axios',
     },