test(src): adds tests for plugin, updates jest.config.js

jest.config.js

@@ -1,8 +1,14 @@
 module.exports = {
   bail: true,
-  collectCoverage: true,
   collectCoverageFrom: ['src/index.ts'],
+  globals: {
+    'ts-jest': {
+      tsconfig: 'tsconfig.test.json',
+    },
+  },
   preset: 'ts-jest',
   roots: ['<rootDir>'],
   testEnvironment: 'node',
+  transform: { '^.+\\.(ts|tsx|js|jsx)?$': 'ts-jest' },
+  transformIgnorePatterns: ['[/\\\\]node_modules[/\\\\].+\\.(ts|tsx)$'],
 }

package.json

@@ -59,6 +59,7 @@
     "jest": "^26.6.3",
     "lint-staged": "^10.5.4",
     "prettier": "^2.2.1",
+    "rehype": "^11.0.0",
     "standard-version": "^9.2.0",
     "ts-jest": "^26.5.5",
     "typescript": "^4.2.4"

src/__snapshots__/index.test.ts.snap

@@ -0,0 +1,5 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`rehype-code-titles Snapshot w/ title block 1`] = `"<div class=\\"rehype-code-title\\">lib/mdx.ts</div><pre><code class=\\"language-typescript\\"></code></pre>"`;
+
+exports[`rehype-code-titles Snapshot w/out title block 1`] = `"<pre><code class=\\"language-typescript\\"></code></pre>"`;

src/index.test.ts

@@ -0,0 +1,45 @@
+import rehype from 'rehype'
+import dedent from 'dedent'
+import rehypeCodeTitles from './index'
+
+const processHtml = (html: string): string => {
+  return rehype()
+    .data('settings', { fragment: true })
+    .use(rehypeCodeTitles)
+    .processSync(html)
+    .toString()
+}
+
+const classNameWithTitle = 'language-typescript:lib/mdx.ts'
+const className = 'language-typescript'
+
+describe('rehype-code-titles', () => {
+  test('Snapshot w/ title block', () => {
+    const result = processHtml(dedent`
+      <pre><code class="${classNameWithTitle}"></code></pre>
+    `)
+    expect(result).toMatchSnapshot()
+  })
+  test('Snapshot w/out title block', () => {
+    const result = processHtml(dedent`
+      <pre><code class="${className}"></code></pre>
+    `)
+    expect(result).toMatchSnapshot()
+  })
+  test('Contains title block', () => {
+    const result = processHtml(dedent`
+      <pre><code class="${classNameWithTitle}"></code></pre>
+    `)
+    expect(result.includes('div')).toEqual(true)
+    expect(result.includes('rehype-code-title')).toEqual(true)
+    expect(result.includes('lib/mdx.ts')).toEqual(true)
+  })
+  test('Does not contain title block', () => {
+    const result = processHtml(dedent`
+      <pre><code class="${className}"></code></pre>
+    `)
+    expect(result.includes('div')).not.toEqual(true)
+    expect(result.includes('rehype-code-title')).not.toEqual(true)
+    expect(result.includes('lib/mdx.ts')).not.toEqual(true)
+  })
+})

tsconfig.test.json

@@ -0,0 +1,7 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "allowJs": true,
+    "noEmit": true
+  }
+}