test(search-api-graphql): mock the unloadable Prettier peer in its own file

packages/search-api-graphql/test/print-sdl-without-prettier.test.ts

@@ -0,0 +1,26 @@
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it, vi } from 'vitest';
+import { printSchemaModuleSdl } from '../src/print-sdl.js';
+
+// Hoisted above the import above, so the optional peer is unloadable from the
+// first import onwards. This case cannot share a file with the tests that
+// format for real: a mock only reaches a module imported after it, and
+// `vi.resetModules()` does not evict an optional peer Node has already
+// resolved – which made the assertion depend on module-graph ordering.
+vi.mock('prettier', () => {
+  throw new Error('Cannot find package ‘prettier’');
+});
+
+describe('printSchemaModuleSdl without Prettier', () => {
+  it('names the optional Prettier peer when it cannot be loaded', async () => {
+    await expect(
+      printSchemaModuleSdl({
+        modulePath: fileURLToPath(
+          new URL('./fixtures/no-options.mjs', import.meta.url),
+        ),
+      }),
+    ).rejects.toThrowError(
+      /Formatting the SDL requires “prettier”, an optional peer dependency .*, which could not be loaded: /,
+    );
+  });
+});

packages/search-api-graphql/test/print-sdl.test.ts

@@ -2,7 +2,7 @@ import { mkdtemp, readFile, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 import { fileURLToPath } from 'node:url';
-import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { beforeEach, describe, expect, it } from 'vitest';
 import { printSchemaModuleSdl } from '../src/print-sdl.js';
 
 const fixture = (name: string): string =>
@@ -14,11 +14,6 @@ beforeEach(async () => {
   directory = await mkdtemp(join(tmpdir(), 'lde-print-sdl-'));
 });
 
-afterEach(() => {
-  vi.doUnmock('prettier');
-  vi.resetModules();
-});
-
 describe('printSchemaModuleSdl', () => {
   it('prints the contract of the mounted module', async () => {
     const sdl = await printSchemaModuleSdl({
@@ -119,21 +114,4 @@ describe('printSchemaModuleSdl', () => {
       /Cannot load schema module “\/no\/such\/module\.mjs”/,
     );
   });
-
-  it('names the optional Prettier peer when it cannot be loaded', async () => {
-    // Reset first: the tests above have already pulled the real Prettier into
-    // the module graph, and a mock only applies to a module imported after it.
-    vi.resetModules();
-    vi.doMock('prettier', () => {
-      throw new Error('Cannot find package ‘prettier’');
-    });
-    const { printSchemaModuleSdl: printWithoutPrettier } =
-      await import('../src/print-sdl.js');
-
-    await expect(
-      printWithoutPrettier({ modulePath: fixture('no-options.mjs') }),
-    ).rejects.toThrowError(
-      /Formatting the SDL requires “prettier”, an optional peer dependency .*, which could not be loaded: /,
-    );
-  });
 });