feat(wip): add no-async-describe rule

README.md

@@ -80,6 +80,7 @@ for more information about extending configuration files.
 
 | Rule                                                               | Description                                                     | Recommended                                                             | Fixable                                                     |
 | ------------------------------------------------------------------ | --------------------------------------------------------------- | ----------------------------------------------------------------------- | ----------------------------------------------------------- |
+| [no-async-describe](docs/rules/no-async-describe.md)               | Prevent async describe callback                                 |                                                                         |                                                             |
 | [no-disabled-tests](docs/rules/no-disabled-tests.md)               | Disallow disabled tests                                         | ![recommended](https://img.shields.io/badge/-recommended-lightgrey.svg) |                                                             |
 | [no-focused-tests](docs/rules/no-focused-tests.md)                 | Disallow focused tests                                          | ![recommended](https://img.shields.io/badge/-recommended-lightgrey.svg) |                                                             |
 | [no-identical-title](docs/rules/no-identical-title.md)             | Disallow identical titles                                       | ![recommended](https://img.shields.io/badge/-recommended-lightgrey.svg) |                                                             |

docs/rules/no-async-describe.md

@@ -0,0 +1,3 @@
+# Prevent async describe callback (no-async-describe)
+
+TODO

index.js

@@ -1,5 +1,4 @@
-'use strict';
-
+const noAsyncDescribe = require('./rules/no_async_describe');
 const noDisabledTests = require('./rules/no_disabled_tests');
 const noFocusedTests = require('./rules/no_focused_tests');
 const noIdenticalTitle = require('./rules/no_identical_title');
@@ -56,6 +55,7 @@ module.exports = {
     '.snap': snapshotProcessor,
   },
   rules: {
+    'no-async-describe': noAsyncDescribe,
     'no-disabled-tests': noDisabledTests,
     'no-focused-tests': noFocusedTests,
     'no-identical-title': noIdenticalTitle,

rules/__tests__/no_async_describe.test.js

@@ -0,0 +1,43 @@
+const RuleTester = require('eslint').RuleTester;
+const rules = require('../..').rules;
+
+const ruleTester = new RuleTester({
+  parserOptions: {
+    ecmaVersion: 8,
+  },
+});
+
+const expectedErrorMessage = 'No async describe';
+
+ruleTester.run('no-async-describe', rules['no-async-describe'], {
+  valid: [
+    'describe("foo")',
+    'describe("foo", function() {})',
+    'describe("foo", () => {})',
+  ],
+  invalid: [
+    {
+      code: 'describe("foo", async () => {})',
+      errors: [{ message: expectedErrorMessage, line: 1, column: 17 }],
+    },
+    {
+      code: 'describe("foo", async function () {})',
+      errors: [{ message: expectedErrorMessage, line: 1, column: 17 }],
+    },
+    {
+      code: `
+      describe('sample case', () => {
+        it('works', () => {
+          expect(true).toEqual(true);
+        });
+        describe('async', async () => {
+          await new Promise(setImmediate);
+          it('breaks', () => {
+            throw new Error('Fail');
+          });
+        });
+      });`,
+      errors: [{ message: expectedErrorMessage, line: 6, column: 27 }],
+    },
+  ],
+});

rules/no_async_describe.js

@@ -0,0 +1,34 @@
+function isDescribe(node) {
+  return node.type === 'CallExpression' && node.callee.name === 'describe';
+}
+
+function isFunction(node) {
+  return (
+    node.type === 'FunctionExpression' ||
+    node.type === 'ArrowFunctionExpression'
+  );
+}
+
+function isAsync(node) {
+  return node.async;
+}
+
+module.exports = context => {
+  return {
+    CallExpression(node) {
+      if (node && isDescribe(node)) {
+        const callbackFunction = node.arguments[1];
+        if (
+          callbackFunction &&
+          isFunction(callbackFunction) &&
+          isAsync(callbackFunction)
+        ) {
+          context.report({
+            message: 'No async describe',
+            node: callbackFunction,
+          });
+        }
+      }
+    },
+  };
+};