Add Storybook tests

Prevent regressions in our custom components by adding Storybook
testing. Copy Storybook tests from the archived `gravitational/docs`
repo. Add a rough-and-ready Storybook configuration to enable tests to
pass.

One significant complication is that Docusaurus generates a Webpack
configuration when building a docs site. There are Storybook frameworks
and add-ons for Docusaurus that take advantage of Docusaurus's
asset-loading logic, but none are currently being maintained. The
quickest thing we can do is add a separate Webpack configuration that
renders components in Storybook similarly (but not identically) to the
Docusaurus site.

A separate change can refine this approach by, for example:
- Vendoring a Storybook Docusaurus framework
- Migrating Storybook tests to `react-testing-library`

.github/workflows/test.yaml

@@ -8,4 +8,9 @@ jobs:
     runs-on: ubuntu-22.04-2core-arm64
     steps:
     - uses: actions/checkout@v4
-    - run: yarn && yarn test
+    - name: Install deps
+      run: yarn && yarn playwright install
+    - name: Run unit tests
+      run: yarn test
+    - name: Run Storybook tests
+      run: yarn storybook:test-ci

.gitignore

@@ -7,6 +7,7 @@
 # Generated files
 .docusaurus
 .cache-loader
+storybook-static
 
 # Misc
 .env

.storybook/@types/imports.d.ts

@@ -0,0 +1,33 @@
+// Declare modules so Storybook can import assets as expected. Docusaurus
+// handles this on its own, so we need to redeclare these modules here for
+// Storybook.
+
+declare module "*.css";
+
+declare module "*.svg";
+
+declare module "*.svg?react" {
+  const Component: React.StatelessComponent<React.SVGAttributes<SVGElement>>;
+
+  export default Component;
+}
+
+declare module "*.png" {
+  const value: string;
+  export default value;
+}
+
+declare module "*.webp" {
+  const value: string;
+  export default value;
+}
+
+declare module "*.jpg" {
+  const value: string;
+  export default value;
+}
+
+declare module "*.woff2" {
+  const value: string;
+  export default value;
+}

.storybook/main.ts

@@ -0,0 +1,53 @@
+import type { StorybookConfig } from "@storybook/react-webpack5";
+
+const config: StorybookConfig = {
+  framework: "@storybook/react-webpack5",
+  stories: ["../src/**/*.stories.@(js|jsx|ts|tsx)"],
+  addons: ["@storybook/addon-essentials"],
+  webpackFinal: async (config) => {
+    config.module?.rules?.push({
+      test: /\.css$/,
+      use: {
+        loader: "postcss-loader",
+      },
+    });
+
+    const imageRule = config.module?.rules?.find((rule) => {
+      const test = (rule as { test: RegExp }).test;
+
+      if (!test) {
+        return false;
+      }
+
+      return test.test(".svg");
+    }) as { [key: string]: any };
+
+    imageRule.exclude = /\.svg$/;
+
+    config.module?.rules?.push({
+      test: /\.svg$/,
+      use: ["@svgr/webpack"],
+    });
+
+    config.module?.rules?.push({
+      test: /\.tsx?$/,
+      use: [
+        {
+          loader: "ts-loader",
+          options: {
+            logLevel: "INFO",
+            logInfoToStdOut: true,
+            configFile: "tsconfig.storybook.json",
+            // Otherwise, properties added by Storybook trip the TypeScript
+            // checker.
+            transpileOnly: true,
+          },
+        },
+      ],
+      exclude: /node_modules/,
+    });
+
+    return config;
+  },
+};
+export default config;

.storybook/preview.ts

@@ -0,0 +1,16 @@
+import { Preview } from "@storybook/react-webpack5";
+
+// See the following documentation for how this configuration loads CSS styles
+// for Storybook stories:
+// https://storybook.js.org/docs/configure/styling-and-css#import-bundled-css-recommended
+import "../src/styles/variables.css";
+import "../src/styles/fonts-ubuntu.css";
+import "../src/styles/global.css";
+import "../src/styles/media.css";
+import "../src/styles/fonts-lato.css";
+
+const preview: Preview = {
+  parameters: {},
+};
+
+export default preview;

package.json

@@ -23,6 +23,10 @@
     "lint": "yarn base:eslint --fix && yarn base:prettier --write -l",
     "lint-check": "yarn base:eslint && yarn base:prettier --check",
     "markdown-lint": "yarn build-remark && remark --rc-path .remarkrc.mjs 'content/**/docs/pages/**/*.mdx' --quiet --frail --ignore-pattern '**/includes/**' --silently-ignore",
+    "storybook": "storybook dev -p 6006",
+    "storybook:build": "storybook build",
+    "storybook:test-ci": "yarn storybook:build --quiet && npx concurrently -k -s first -n \"SB,TEST\" -c \"magenta,blue\" \"npx http-server storybook-static --port 6006 --silent\" \"npx wait-on tcp:6006 && yarn storybook:test\"",
+    "storybook:test": "test-storybook",
     "test": "NODE_OPTIONS=\"$NODE_OPTIONS --trace-warnings --experimental-vm-modules\" jest --config ./jest.server.config.mjs server/*.test.ts"
   },
   "lint-staged": {
@@ -68,21 +72,29 @@
   "devDependencies": {
     "@docusaurus/module-type-aliases": "^3.6.3",
     "@docusaurus/types": "^3.6.3",
+    "@storybook/addon-essentials": "^8.5.2",
+    "@storybook/addon-webpack5-compiler-swc": "^2.0.0",
+    "@storybook/react": "^8.5.2",
+    "@storybook/react-webpack5": "^8.5.2",
+    "@storybook/test": "^8.5.2",
+    "@storybook/test-runner": "^0.21.0",
+    "@svgr/webpack": "^8.1.0",
     "@types/react": "^18.3.3",
     "ajv": "^8.16.0",
     "hast": "^1.0.0",
     "jest": "^29.7.0",
     "js-yaml": "^4.1.0",
     "loadr": "^0.1.1",
+    "mdast": "^3.0.0",
     "mdast-util-from-markdown": "^2.0.1",
     "mdast-util-frontmatter": "^2.0.1",
     "mdast-util-gfm": "^3.0.0",
     "mdast-util-mdx": "^3.0.0",
-    "mdast": "^3.0.0",
     "micromark-extension-frontmatter": "^2.0.0",
     "micromark-extension-gfm": "^3.0.0",
     "micromark-extension-mdxjs": "^3.0.0",
     "postcss": "^8.4.38",
+    "postcss-loader": "^8.1.1",
     "rehype-stringify": "^10.0.1",
     "remark-cli": "10.0.1",
     "remark-copy-linked-files": "^1.5.0",
@@ -92,16 +104,18 @@
     "remark-preset-lint-markdown-style-guide": "^5.1.2",
     "remark-rehype": "^10.1.0",
     "remark-validate-links": "^11.0.2",
+    "storybook": "^8.5.2",
     "to-vfile": "^8.0.0",
     "ts-jest": "^29.2.5",
+    "ts-loader": "^9.5.2",
     "tsc-esm-fix": "^3.1.0",
     "tsm": "^2.3.0",
     "typescript": "~5.5.2",
-    "unified-lint-rule": "^3.0.0",
     "unified": "^11.0.5",
+    "unified-lint-rule": "^3.0.0",
+    "unist": "^0.0.1",
     "unist-util-find": "^3.0.0",
     "unist-util-visit-parents": "^6.0.1",
-    "unist": "^0.0.1",
     "vfile": "^6.0.1"
   },
   "browserslist": {

src/components/Command/Command.stories.tsx

@@ -0,0 +1,34 @@
+import type { Meta, StoryObj } from "@storybook/react";
+import { userEvent, within } from "@storybook/test";
+import { replaceClipboardWithCopyBuffer } from "/src/utils/clipboard";
+
+import Command from "./Command";
+
+const commandText = "yarn install";
+
+const meta: Meta<typeof Command> = {
+  title: "components/Command",
+  component: Command,
+  args: {
+    children: <span>{commandText}</span>,
+  },
+};
+export default meta;
+type Story = StoryObj<typeof Command>;
+
+export const SimpleCommand: Story = {
+  args: {
+    children: <span>{commandText}</span>,
+  },
+};
+
+export const CopyButton: Story = {
+  play: async ({ canvasElement, step }) => {
+    replaceClipboardWithCopyBuffer();
+    const canvas = within(canvasElement);
+    await step("Hover and click on copy button", async () => {
+      await userEvent.hover(canvas.getByTestId("copy-button"));
+      await userEvent.click(canvas.getByTestId("copy-button"));
+    });
+  },
+};

src/components/Snippet/Snippet.stories.tsx

@@ -0,0 +1,115 @@
+import type { Meta, StoryObj } from "@storybook/react";
+import { userEvent, within } from "@storybook/test";
+import { expect } from "@storybook/test";
+
+import { Var } from "../Variables/Var";
+import { default as Snippet } from "./Snippet";
+import Command, { CommandLine, CommandComment } from "../Command/Command";
+import { CodeLine } from "/src/theme/MDXComponents/Code";
+import { replaceClipboardWithCopyBuffer } from "/src/utils/clipboard";
+
+export const SimpleCommand = () => (
+  <Snippet>
+    <Command>
+      <CommandLine data-content="$ ">echo Hello world!</CommandLine>
+    </Command>
+  </Snippet>
+);
+
+const meta: Meta<typeof Snippet> = {
+  title: "components/Snippet",
+  component: SimpleCommand,
+};
+export default meta;
+type Story = StoryObj<typeof Snippet>;
+
+export const CopyCommandVar: Story = {
+  render: () => {
+    return (
+      <Snippet>
+        <Command>
+          <CommandLine data-content="$ ">
+            curl https://
+            <Var name="example.com" isGlobal={false} description="" />
+            /v1/webapi/saml/acs/azure-saml
+          </CommandLine>
+        </Command>
+      </Snippet>
+    );
+  },
+  play: async ({ canvasElement, step }) => {
+    replaceClipboardWithCopyBuffer();
+    const canvas = within(canvasElement);
+
+    await step("Copy the content", async () => {
+      await userEvent.hover(canvas.getByText("example.com"));
+      await userEvent.click(canvas.getByTestId("copy-button"));
+      expect(navigator.clipboard.readText()).toEqual(
+        "curl https://example.com/v1/webapi/saml/acs/azure-saml",
+      );
+      await userEvent.click(canvas.getByTestId("copy-button-all"));
+      expect(navigator.clipboard.readText()).toEqual(
+        "curl https://example.com/v1/webapi/saml/acs/azure-saml",
+      );
+    });
+  },
+};
+
+// A code snippet with commands should only copy the commands.
+export const CopyCommandVarWithOutput: Story = {
+  render: () => {
+    return (
+      <Snippet>
+        <Command>
+          <CommandLine data-content="$ ">
+            curl https://
+            <Var name="example.com" isGlobal={false} description="" />
+            /v1/webapi/saml/acs/azure-saml
+          </CommandLine>
+        </Command>
+        <CodeLine>
+          The output of curling <Var name="example.com" />
+        </CodeLine>
+      </Snippet>
+    );
+  },
+  play: async ({ canvasElement, step }) => {
+    replaceClipboardWithCopyBuffer();
+    const canvas = within(canvasElement);
+
+    await step("Copy the content", async () => {
+      await userEvent.click(canvas.getByTestId("copy-button-all"));
+      expect(navigator.clipboard.readText()).toEqual(
+        "curl https://example.com/v1/webapi/saml/acs/azure-saml",
+      );
+    });
+  },
+};
+
+// A code snippet with no commands should copy all content within the snippet.
+export const CopyCodeLineVar: Story = {
+  render: () => {
+    return (
+      <Snippet>
+        <CodeLine>
+          curl https://
+          <Var name="example.com" isGlobal={false} description="" />
+          /v1/webapi/saml/acs/azure-saml
+        </CodeLine>
+      </Snippet>
+    );
+  },
+  play: async ({ canvasElement, step }) => {
+    replaceClipboardWithCopyBuffer();
+
+    const canvas = within(canvasElement);
+
+    await step("Copy the content", async () => {
+      await userEvent.hover(canvas.getByText("example.com"));
+      await userEvent.click(canvas.getByTestId("copy-button-all"));
+      expect(navigator.clipboard.readText()).toEqual(
+        "curl https://example.com/v1/webapi/saml/acs/azure-saml",
+      );
+    });
+  },
+};