test(api/format): add some coverage

Author: jrolfs

src/api/__mocks__/prettier.js

@@ -0,0 +1,3 @@
+module.exports = {
+  format: jest.fn(() => '[formatted-code]'),
+}

src/api/__tests__/__snapshots__/api.js.snap

@@ -0,0 +1,44 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`format calls \`prettier.format\` with internal Prettier configuration 1`] = `
+Object {
+  "arrowParens": "avoid",
+  "bracketSpacing": true,
+  "endOfLine": "lf",
+  "htmlWhitespaceSensitivity": "css",
+  "insertPragma": false,
+  "jsxBracketSameLine": false,
+  "jsxSingleQuote": false,
+  "printWidth": 80,
+  "proseWrap": "always",
+  "quoteProps": "as-needed",
+  "requirePragma": false,
+  "semi": true,
+  "singleQuote": true,
+  "tabWidth": 2,
+  "trailingComma": "all",
+  "useTabs": false,
+}
+`;
+
+exports[`format merges provided \`options\` with internal Prettier configuration 1`] = `
+Object {
+  "arrowParens": "always",
+  "bracketSpacing": true,
+  "endOfLine": "lf",
+  "htmlWhitespaceSensitivity": "css",
+  "insertPragma": false,
+  "jsxBracketSameLine": false,
+  "jsxSingleQuote": false,
+  "parser": "css",
+  "printWidth": 100,
+  "proseWrap": "always",
+  "quoteProps": "as-needed",
+  "requirePragma": false,
+  "semi": true,
+  "singleQuote": true,
+  "tabWidth": 2,
+  "trailingComma": "all",
+  "useTabs": false,
+}
+`;

src/api/__tests__/api.js

@@ -0,0 +1,34 @@
+import cases from 'jest-in-case'
+import prettier from 'prettier'
+import {format} from '../'
+
+cases(
+  'format',
+  ({source = 'const id = x => x', options = {}}) => {
+    // beforeEach
+    format(source, options)
+
+    try {
+      expect(prettier.format).toHaveBeenCalledTimes(1)
+      expect(prettier.format).toHaveBeenCalledWith(source, expect.any(Object))
+
+      const [call] = prettier.format.mock.calls
+
+      expect(call[1]).toMatchSnapshot()
+    } catch (error) {
+      throw error
+    } finally {
+      // afterEach
+
+      prettier.format.mockReset()
+      jest.resetModules()
+    }
+  },
+  {
+    'calls `prettier.format` with internal Prettier configuration': {},
+    'merges provided `options` with internal Prettier configuration': {
+      /** @type {import('prettier').Options} */
+      options: {printWidth: 100, arrowParens: 'always', parser: 'css'},
+    },
+  },
+)

src/tsconfig.json

@@ -1,6 +1,7 @@
 {
   "extends": "./config/tsconfig.json",
   "include": ["./api"],
+  "exclude": ["./**/__tests__/*"],
   "compilerOptions": {
     "allowJs": true,
     "checkJs": true,