add unit tests

packages/docusaurus/src/server/__tests__/siteMessages.test.ts

@@ -0,0 +1,66 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import path from 'path';
+import {fromPartial} from '@total-typescript/shoehorn';
+import {collectAllSiteMessages} from '../siteMessages';
+
+function siteDirFixture(name: string) {
+  return path.resolve(__dirname, '__fixtures__', 'siteMessages', name);
+}
+
+describe('collectAllSiteMessages', () => {
+  describe('uselessBabelConfigMessages', () => {
+    async function getMessagesFor({
+      siteDir,
+      swcJsLoader,
+    }: {
+      siteDir: string;
+      swcJsLoader: boolean;
+    }) {
+      return collectAllSiteMessages(
+        fromPartial({
+          site: {
+            props: {
+              siteDir,
+              siteConfig: {
+                future: {
+                  experimental_faster: {
+                    swcJsLoader,
+                  },
+                },
+              },
+            },
+          },
+        }),
+      );
+    }
+
+    it('warns for useless babel config file when SWC enabled', async () => {
+      const messages = await getMessagesFor({
+        siteDir: siteDirFixture('siteWithBabelConfigFile'),
+        swcJsLoader: true,
+      });
+      expect(messages).toMatchInlineSnapshot(`
+              [
+                {
+                  "message": "Your site is using the SWC js loader. You can safely remove the Babel config file at \`packages/docusaurus/src/server/__tests__/__fixtures__/siteMessages/siteWithBabelConfigFile/babel.config.js\`.",
+                  "type": "warning",
+                },
+              ]
+          `);
+    });
+
+    it('does not warn for babel config file when SWC disabled', async () => {
+      const messages = await getMessagesFor({
+        siteDir: siteDirFixture('siteWithBabelConfigFile'),
+        swcJsLoader: false,
+      });
+      expect(messages).toMatchInlineSnapshot(`[]`);
+    });
+  });
+});

packages/docusaurus/src/server/siteMessages.ts

@@ -37,7 +37,9 @@ const uselessBabelConfigMessages: SiteMessageCreator = async ({site}) => {
   return [];
 };
 
-async function collectAllSiteMessages(params: Params): Promise<SiteMessage[]> {
+export async function collectAllSiteMessages(
+  params: Params,
+): Promise<SiteMessage[]> {
   const messageCreators: SiteMessageCreator[] = [uselessBabelConfigMessages];
   return (
     await Promise.all(