From 9895ab62e36de0fd2219089ed9b07618e61b02b0 Mon Sep 17 00:00:00 2001
From: Macklin Underdown <macklinu@users.noreply.github.com>
Date: Sat, 3 Feb 2018 13:35:54 -0500
Subject: [PATCH] feat(wip): add no-async-describe rule

---
 README.md                                 |  1 +
 docs/rules/no-async-describe.md           |  3 ++
 index.js                                  |  4 +--
 rules/__tests__/no_async_describe.test.js | 43 +++++++++++++++++++++++
 rules/no_async_describe.js                | 34 ++++++++++++++++++
 5 files changed, 83 insertions(+), 2 deletions(-)
 create mode 100644 docs/rules/no-async-describe.md
 create mode 100644 rules/__tests__/no_async_describe.test.js
 create mode 100644 rules/no_async_describe.js

diff --git a/README.md b/README.md
index cbbd8e232..d9a8685cc 100644
--- a/README.md
+++ b/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) |                                                             |
diff --git a/docs/rules/no-async-describe.md b/docs/rules/no-async-describe.md
new file mode 100644
index 000000000..9f16adf28
--- /dev/null
+++ b/docs/rules/no-async-describe.md
@@ -0,0 +1,3 @@
+# Prevent async describe callback (no-async-describe)
+
+TODO
diff --git a/index.js b/index.js
index d3eac65e4..42ce4508c 100644
--- a/index.js
+++ b/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,
diff --git a/rules/__tests__/no_async_describe.test.js b/rules/__tests__/no_async_describe.test.js
new file mode 100644
index 000000000..c3c0777fd
--- /dev/null
+++ b/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 }],
+    },
+  ],
+});
diff --git a/rules/no_async_describe.js b/rules/no_async_describe.js
new file mode 100644
index 000000000..c44a00f94
--- /dev/null
+++ b/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,
+          });
+        }
+      }
+    },
+  };
+};