test: improve test coverage; properly test core client APIs (#6905)

* test: improve test coverage

* fix

packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/globalData.test.ts.snap

@@ -0,0 +1,43 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`toGlobalDataVersion generates the right docs, sidebars, and metadata 1`] = `
+Object {
+  "docs": Array [
+    Object {
+      "id": "main",
+      "path": "/current/main",
+      "sidebar": "tutorial",
+    },
+    Object {
+      "id": "doc",
+      "path": "/current/doc",
+      "sidebar": "tutorial",
+    },
+    Object {
+      "id": "/current/generated",
+      "path": "/current/generated",
+      "sidebar": "tutorial",
+    },
+  ],
+  "isLast": true,
+  "label": "Label",
+  "mainDocId": "main",
+  "name": "current",
+  "path": "/current",
+  "sidebars": Object {
+    "another": Object {
+      "link": Object {
+        "label": "Generated",
+        "path": "/current/generated",
+      },
+    },
+    "links": Object {},
+    "tutorial": Object {
+      "link": Object {
+        "label": "main",
+        "path": "/current/main",
+      },
+    },
+  },
+}
+`;

packages/docusaurus-plugin-content-docs/src/__tests__/globalData.test.ts

@@ -0,0 +1,100 @@
+/**
+ * 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 {toGlobalDataVersion} from '../globalData';
+
+describe('toGlobalDataVersion', () => {
+  it('generates the right docs, sidebars, and metadata', () => {
+    expect(
+      toGlobalDataVersion({
+        versionName: 'current',
+        versionLabel: 'Label',
+        isLast: true,
+        versionPath: '/current',
+        mainDocId: 'main',
+        docs: [
+          {
+            unversionedId: 'main',
+            permalink: '/current/main',
+            sidebar: 'tutorial',
+          },
+          {
+            unversionedId: 'doc',
+            permalink: '/current/doc',
+            sidebar: 'tutorial',
+          },
+        ],
+        sidebars: {
+          another: [
+            {
+              type: 'category',
+              label: 'Generated',
+              link: {
+                type: 'generated-index',
+                permalink: '/current/generated',
+              },
+              items: [
+                {
+                  type: 'doc',
+                  id: 'doc',
+                },
+              ],
+            },
+          ],
+          tutorial: [
+            {
+              type: 'doc',
+              id: 'main',
+            },
+            {
+              type: 'category',
+              label: 'Generated',
+              link: {
+                type: 'generated-index',
+                permalink: '/current/generated',
+              },
+              items: [
+                {
+                  type: 'doc',
+                  id: 'doc',
+                },
+              ],
+            },
+          ],
+          links: [
+            {
+              type: 'link',
+              href: 'foo',
+              label: 'Foo',
+            },
+            {
+              type: 'link',
+              href: 'bar',
+              label: 'Bar',
+            },
+          ],
+        },
+        categoryGeneratedIndices: [
+          {
+            title: 'Generated',
+            slug: '/current/generated',
+            permalink: '/current/generated',
+            sidebar: 'tutorial',
+          },
+        ],
+        versionBanner: 'unreleased',
+        versionBadge: true,
+        versionClassName: 'current-cls',
+        tagsPath: '/current/tags',
+        contentPath: '',
+        contentPathLocalized: '',
+        sidebarFilePath: '',
+        routePriority: 0.5,
+      }),
+    ).toMatchSnapshot();
+  });
+});

packages/docusaurus-plugin-content-docs/src/__tests__/slug.test.ts

@@ -111,6 +111,27 @@ describe('getSlug', () => {
     ).toBe('/dir with spâce/hey $hello/my dôc');
   });
 
+  it('throws for invalid routes', () => {
+    expect(() =>
+      getSlug({
+        baseID: 'my dôc',
+        source: '@site/docs/dir with spâce/hey $hello/doc.md',
+        sourceDirName: '/dir with spâce/hey $hello',
+        frontMatterSlug: '//',
+      }),
+    ).toThrowErrorMatchingInlineSnapshot(`
+      "We couldn't compute a valid slug for document with ID \\"my dôc\\" in \\"/dir with spâce/hey $hello\\" directory.
+      The slug we computed looks invalid: //.
+      Maybe your slug front matter is incorrect or there are special characters in the file path?
+      By using front matter to set a custom slug, you should be able to fix this error:
+
+      ---
+      slug: /my/customDocPath
+      ---
+      "
+    `);
+  });
+
   it('handles current dir', () => {
     expect(
       getSlug({baseID: 'doc', source: '@site/docs/doc.md', sourceDirName: '.'}),