Merge pull request #227 from playwright-community/no-duplicate-hooks

feat: Add `no-duplicate-hooks` rule

Author: mskelton

README.md

@@ -125,6 +125,7 @@ command line option.\
 |     |     |     | [no-commented-out-test](https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-commented-out-test.md)             | Disallow commented out tests                                      |
 | ✔  |     |     | [no-conditional-expect](https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-conditional-expect.md)             | Disallow calling `expect` conditionally                           |
 | ✔  |     |     | [no-conditional-in-test](https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-conditional-in-test.md)           | Disallow conditional logic in tests                               |
+|     |     |     | [no-duplicate-hooks](https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-duplicate-hooks.md)                   | Disallow duplicate setup and teardown hooks                       |
 | ✔  |     | 💡  | [no-element-handle](https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-element-handle.md)                     | Disallow usage of element handles                                 |
 | ✔  |     |     | [no-eval](https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-eval.md)                                         | Disallow usage of `page.$eval()` and `page.$$eval()`              |
 | ✔  |     | 💡  | [no-focused-test](https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-focused-test.md)                         | Disallow usage of `.only` annotation                              |

docs/rules/no-duplicate-hooks.md

@@ -0,0 +1,75 @@
+# Disallow duplicate setup and teardown hooks (`no-duplicate-hooks`)
+
+A `describe` block should not contain duplicate hooks.
+
+## Rule details
+
+Examples of **incorrect** code for this rule
+
+```js
+/* eslint playwright/no-duplicate-hooks: "error" */
+
+test.describe('foo', () => {
+  test.beforeEach(() => {
+    // some setup
+  });
+  test.beforeEach(() => {
+    // some setup
+  });
+  test('foo_test', () => {
+    // some test
+  });
+});
+
+// Nested describe scenario
+test.describe('foo', () => {
+  test.beforeEach(() => {
+    // some setup
+  });
+  test('foo_test', () => {
+    // some test
+  });
+  test.describe('bar', () => {
+    test('bar_test', () => {
+      test.afterAll(() => {
+        // some teardown
+      });
+      test.afterAll(() => {
+        // some teardown
+      });
+    });
+  });
+});
+```
+
+Examples of **correct** code for this rule
+
+```js
+/* eslint playwright/no-duplicate-hooks: "error" */
+
+test.describe('foo', () => {
+  test.beforeEach(() => {
+    // some setup
+  });
+  test('foo_test', () => {
+    // some test
+  });
+});
+
+// Nested describe scenario
+test.describe('foo', () => {
+  test.beforeEach(() => {
+    // some setup
+  });
+  test('foo_test', () => {
+    // some test
+  });
+  test.describe('bar', () => {
+    test('bar_test', () => {
+      test.beforeEach(() => {
+        // some setup
+      });
+    });
+  });
+});
+```

src/index.ts

@@ -5,6 +5,7 @@ import missingPlaywrightAwait from './rules/missing-playwright-await';
 import noCommentedOutTests from './rules/no-commented-out-tests';
 import noConditionalExpect from './rules/no-conditional-expect';
 import noConditionalInTest from './rules/no-conditional-in-test';
+import noDuplicateHooks from './rules/no-duplicate-hooks';
 import noElementHandle from './rules/no-element-handle';
 import noEval from './rules/no-eval';
 import noFocusedTest from './rules/no-focused-test';
@@ -46,6 +47,7 @@ const index = {
     'no-commented-out-tests': noCommentedOutTests,
     'no-conditional-expect': noConditionalExpect,
     'no-conditional-in-test': noConditionalInTest,
+    'no-duplicate-hooks': noDuplicateHooks,
     'no-element-handle': noElementHandle,
     'no-eval': noEval,
     'no-focused-test': noFocusedTest,

src/rules/no-duplicate-hooks.ts

@@ -0,0 +1,54 @@
+import { Rule } from 'eslint';
+import { getStringValue, isDescribeCall, isTestHook } from '../utils/ast';
+
+export default {
+  create(context) {
+    const hookContexts: Array<Record<string, number>> = [{}];
+
+    return {
+      CallExpression(node) {
+        if (isDescribeCall(node)) {
+          hookContexts.push({});
+        }
+
+        if (!isTestHook(context, node)) {
+          return;
+        }
+
+        const currentLayer = hookContexts[hookContexts.length - 1];
+        const name =
+          node.callee.type === 'MemberExpression'
+            ? getStringValue(node.callee.property)
+            : '';
+
+        currentLayer[name] ||= 0;
+        currentLayer[name] += 1;
+
+        if (currentLayer[name] > 1) {
+          context.report({
+            data: { hook: name },
+            messageId: 'noDuplicateHook',
+            node,
+          });
+        }
+      },
+      'CallExpression:exit'(node) {
+        if (isDescribeCall(node)) {
+          hookContexts.pop();
+        }
+      },
+    };
+  },
+  meta: {
+    docs: {
+      category: 'Best Practices',
+      description: 'Disallow duplicate setup and teardown hooks',
+      recommended: false,
+      url: 'https://github.com/playwright-community/eslint-plugin-playwright/tree/main/docs/rules/no-duplicate-hooks.md',
+    },
+    messages: {
+      noDuplicateHook: 'Duplicate {{ hook }} in describe block',
+    },
+    type: 'suggestion',
+  },
+} as Rule.RuleModule;