test: add test for merging global fs breadcrumbs

packages/plugins/src/BreadcrumbsPlugin.ts

@@ -83,36 +83,38 @@ const BreadcrumbsPlugin: PluginType<BreadcrumbsPluginPage, BreadcrumbsPluginOpti
       // the root breadcrumb is the first breadcrumb for all pages in a source.  It is essentially the "first" page in a source
       const rootBreadcrumb = breadcrumbs?.[0] || undefined;
 
-      let parentDir = path.posix.join(path.posix.dirname(rootBreadcrumb.id), '../');
-
-      while (parentDir !== '/') {
-        const parentDirIndex = path.posix.join(parentDir, options.indexPageName);
-
-        // check for this file in the global fs so we have a holistic view of all site pages
-        if (await globalFilesystem.promises.exists(parentDirIndex)) {
-          const { breadcrumbs: parentDirBreadcrumbs } = await serialiser.deserialise(
-            rootBreadcrumb.id,
-            await globalFilesystem.promises.readFile(parentDirIndex)
-          );
-          updatedBreadcrumbs = parentDirBreadcrumbs;
-          break;
+      if (rootBreadcrumb) {
+        let parentDir = path.posix.join(path.posix.dirname(rootBreadcrumb.id), '../');
+
+        while (parentDir !== '/') {
+          const parentDirIndex = path.posix.join(parentDir, options.indexPageName);
+
+          // check for this file in the global fs so we have a holistic view of all site pages
+          if (await globalFilesystem.promises.exists(parentDirIndex)) {
+            const { breadcrumbs: parentDirBreadcrumbs } = await serialiser.deserialise(
+              rootBreadcrumb.id,
+              await globalFilesystem.promises.readFile(parentDirIndex)
+            );
+            updatedBreadcrumbs = parentDirBreadcrumbs;
+            break;
+          }
+          parentDir = path.posix.join(path.posix.dirname(parentDirIndex), '../');
         }
-        parentDir = path.posix.join(path.posix.dirname(parentDirIndex), '../');
-      }
 
-      if (updatedBreadcrumbs.length > 0) {
-        for (const pagePath of pages) {
-          const page = await serialiser.deserialise(
-            pagePath,
-            await mutableFilesystem.promises.readFile(pagePath)
-          );
-
-          // append the parent breadcrumbs **before** the current breadcrumbs
-          page.breadcrumbs = [...updatedBreadcrumbs, ...page.breadcrumbs];
-          await mutableFilesystem.promises.writeFile(
-            pagePath,
-            await serialiser.serialise(pagePath, page)
-          );
+        if (updatedBreadcrumbs.length > 0) {
+          for (const pagePath of pages) {
+            const page = await serialiser.deserialise(
+              pagePath,
+              await mutableFilesystem.promises.readFile(pagePath)
+            );
+
+            // append the parent breadcrumbs **before** the current breadcrumbs
+            page.breadcrumbs = [...updatedBreadcrumbs, ...page.breadcrumbs];
+            await mutableFilesystem.promises.writeFile(
+              pagePath,
+              await serialiser.serialise(pagePath, page)
+            );
+          }
         }
       }
     }

packages/plugins/src/__tests__/BreadcrumbsPlugin.test.ts

@@ -1,3 +1,4 @@
+import { serialize } from 'v8';
 import BreadcrumbsPlugin, { BreadcrumbsPluginPage } from '../BreadcrumbsPlugin';
 
 const pages: BreadcrumbsPluginPage[] = [
@@ -57,23 +58,76 @@ const pages: BreadcrumbsPluginPage[] = [
   }
 ];
 
+const mutableFsPages = [
+  {
+    fullPath: '/FolderA/SubfolderA/SubfolderB/index.mdx',
+    route: 'route/folderA/subfolderA/SubfolderB/index',
+    title: 'Subfolder A Subfolder B Index',
+    layout: 'DetailOverview',
+    breadcrumbs: [
+      {
+        label: 'Subfolder B Index',
+        path: 'route/folderA/subfolderA/SubfolderB/index',
+        id: '/FolderA/SubfolderA/SubfolderB/index.mdx'
+      }
+    ]
+  }
+];
+
+let writeFileMock = jest.fn();
+const volume = {
+  promises: {
+    exists: jest.fn(),
+    glob: jest.fn().mockResolvedValue(mutableFsPages.map(page => page.fullPath)),
+    mkdir: jest.fn(),
+    readdir: jest.fn(),
+    readFile: jest.fn(value =>
+      Promise.resolve(mutableFsPages.find(page => page.fullPath === value))
+    ),
+    realpath: jest.fn(),
+    stat: jest.fn(),
+    symlink: jest.fn(),
+    unlink: jest.fn(),
+    writeFile: writeFileMock
+  }
+};
+const globalVolume = {
+  promises: {
+    exists: jest.fn().mockResolvedValue(true),
+    glob: jest.fn().mockResolvedValue(pages.map(page => page.fullPath)),
+    mkdir: jest.fn(),
+    readdir: jest.fn(),
+    readFile: jest.fn(value =>
+      Promise.resolve(mutableFsPages.find(page => page.fullPath === value))
+    ),
+    realpath: jest.fn(),
+    stat: jest.fn(),
+    symlink: jest.fn(),
+    unlink: jest.fn(),
+    writeFile: writeFileMock
+  }
+};
+
 describe('GIVEN the BreadcrumbsPlugin', () => {
-  let updatedPages: BreadcrumbsPluginPage[] = [];
-  beforeEach(async () => {
-    const $afterSource = BreadcrumbsPlugin.$afterSource;
-    updatedPages =
-      (await $afterSource?.(
-        pages,
-        { ignorePages: ['sidebar.json'], pageExtensions: ['.mdx'] },
-        { indexPageName: 'index.mdx' }
-      )) || [];
+  test('THEN it should use the `$afterSource` lifecycle event', () => {
+    expect(BreadcrumbsPlugin).toHaveProperty('$afterSource');
   });
 
-  test('THEN it should use the `$afterSource` lifecycle event', () => {
+  test('THEN it should use the `afterUpdate` lifecycle event', () => {
     expect(BreadcrumbsPlugin).toHaveProperty('afterUpdate');
   });
 
   describe('AND WHEN `$afterSource` is called', () => {
+    let updatedPages: BreadcrumbsPluginPage[] = [];
+    beforeEach(async () => {
+      const $afterSource = BreadcrumbsPlugin.$afterSource;
+      updatedPages =
+        (await $afterSource?.(
+          pages,
+          { ignorePages: ['sidebar.json'], pageExtensions: ['.mdx'] },
+          { indexPageName: 'index.mdx' }
+        )) || [];
+    });
     test('THEN breadcrumbs are added', async () => {
       const breadcrumbs = (updatedPages && updatedPages[4].breadcrumbs) || [];
 
@@ -112,4 +166,66 @@ describe('GIVEN the BreadcrumbsPlugin', () => {
       });
     });
   });
+
+  /**
+   * This test requires a bit of setup and understanding
+   *
+   * The goal is for there to be a file in a mutable filesystem that
+   * needs breadcrumbs from the global filesystem.
+   *
+   * To facilitate this the mutable fs has 1 page which should get the breadcrumbs from the 4th page in the global fs
+   *
+   * deserialise will be called 3 times by this plugin event so we use mockReturnValueOnce 3 times
+   * 1. to read the page from the mutable fs
+   * 2. to read the 4th page from the global fs
+   * 3. to read the page from the mutable fs again
+   *
+   */
+
+  describe('AND WHEN `afterUpdate` is called', () => {
+    let serialiseMock = jest.fn();
+    beforeEach(async () => {
+      const afterUpdate = BreadcrumbsPlugin.afterUpdate;
+
+      (await afterUpdate?.(
+        volume,
+        {
+          globalFilesystem: globalVolume,
+          ignorePages: ['sidebar.json'],
+          pageExtensions: ['.mdx'],
+          serialiser: {
+            deserialise: jest
+              .fn()
+              .mockResolvedValueOnce(mutableFsPages[0])
+              .mockResolvedValueOnce(pages[3])
+              .mockResolvedValueOnce(mutableFsPages[0]),
+            serialise: serialiseMock
+          }
+        },
+        { indexPageName: 'index.mdx' }
+      )) || [];
+    });
+    test('THEN breadcrumbs from global fs are added', async () => {
+      expect(writeFileMock).toBeCalledTimes(1);
+      expect(serialiseMock).toBeCalledTimes(1);
+      expect(serialiseMock.mock.calls[0][0]).toEqual('/FolderA/SubfolderA/SubfolderB/index.mdx');
+      expect(serialiseMock.mock.calls[0][1].breadcrumbs).toEqual([
+        {
+          label: 'Folder A Index',
+          path: 'route/folderA/index',
+          id: '/FolderA/index.mdx'
+        },
+        {
+          label: 'Subfolder A Index',
+          path: 'route/folderA/subfolderA/index',
+          id: '/FolderA/SubfolderA/index.mdx'
+        },
+        {
+          label: 'Subfolder B Index',
+          path: 'route/folderA/subfolderA/SubfolderB/index',
+          id: '/FolderA/SubfolderA/SubfolderB/index.mdx'
+        }
+      ]);
+    });
+  });
 });