feat(rule): add data-testid rule (#56)

* feat(rule): add data-testid rule

* chore(consistent-data-testid): address pr feedback

* feat(testid): support configurable attribute

* chore(consistent-data-testid): update docs

* chore(consistent-data-testid): fix coverage

README.md

@@ -138,6 +138,7 @@ To enable this configuration use the `extends` property in your
 | [no-dom-import](docs/rules/no-dom-import.md)                   | Disallow importing from DOM Testing Library                         | ![angular-badge][] ![react-badge][] ![vue-badge][]                        | ![fixable-badge][] |
 | [prefer-expect-query-by](docs/rules/prefer-expect-query-by.md) | Disallow the use of `expect(getBy*)`                                | ![recommended-badge][] ![angular-badge][] ![react-badge][] ![vue-badge][] |                    |
 | [prefer-explicit-assert](docs/rules/prefer-explicit-assert.md) | Suggest using explicit assertions rather than just `getBy*` queries |                                                                           |                    |
+| [consistent-data-testid](docs/rules/consistent-data-testid.md) | Ensure `data-testid` values match a provided regex.                 |                                                                           |                    |
 
 [build-badge]: https://img.shields.io/travis/Belco90/eslint-plugin-testing-library?style=flat-square
 [build-url]: https://travis-ci.org/belco90/eslint-plugin-testing-library

docs/rules/consistent-data-testid.md

@@ -0,0 +1,43 @@
+# Enforces consistent naming for the data-testid attribute (consistent-data-testid)
+
+Ensure `data-testid` values match a provided regex. This rule is un-opinionated, and requires configuration.
+
+## Rule Details
+
+> Assuming the rule has been configured with the following regex: `^TestId(\_\_[A-Z]*)?$`
+
+Examples of **incorrect** code for this rule:
+
+```js
+const foo = props => <div data-testid="my-test-id">...</div>;
+const foo = props => <div data-testid="myTestId">...</div>;
+const foo = props => <div data-testid="TestIdEXAMPLE">...</div>;
+```
+
+Examples of **correct** code for this rule:
+
+```js
+const foo = props => <div data-testid="TestId__EXAMPLE">...</div>;
+const bar = props => <div data-testid="TestId">...</div>;
+const baz = props => <div>...</div>;
+```
+
+## Options
+
+| Option            | Required | Default       | Details                                                                                                                                                                                                                                                       | Example                                |
+| ----------------- | -------- | ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------- |
+| `testIdPattern`   | Yes      | None          | A regex used to validate the format of the `data-testid` value. `{fileName}` can optionally be used as a placeholder and will be substituted with the name of the file OR the name of the files parent directory in the case when the file name is `index.js` | `^{fileName}(\_\_([A-Z]+[a-z]_?)+)_\$` |
+| `testIdAttribute` | No       | `data-testid` | A string used to specify the attribute used for querying by ID. This is only required if data-testid has been explicitly overridden in the [RTL configuration](https://testing-library.com/docs/dom-testing-library/api-queries#overriding-data-testid)       | `data-my-test-attribute`               |
+
+## Example
+
+```json
+{
+  "testing-library/data-testid": [
+    2,
+    {
+      "testIdPattern": "^TestId(__[A-Z]*)?$"
+    }
+  ]
+}
+```

lib/index.js

@@ -3,6 +3,7 @@
 const rules = {
   'await-async-query': require('./rules/await-async-query'),
   'await-fire-event': require('./rules/await-fire-event'),
+  'consistent-data-testid': require('./rules/consistent-data-testid'),
   'no-await-sync-query': require('./rules/no-await-sync-query'),
   'no-debug': require('./rules/no-debug'),
   'no-dom-import': require('./rules/no-dom-import'),

lib/rules/consistent-data-testid.js

@@ -0,0 +1,75 @@
+'use strict';
+
+const FILENAME_PLACEHOLDER = '{fileName}';
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Ensures consistent usage of `data-testid`',
+      category: 'Best Practices',
+      recommended: false,
+    },
+    messages: {
+      invalidTestId: '`{{attr}}` "{{value}}" should match `{{regex}}`',
+    },
+    fixable: null,
+    schema: [
+      {
+        type: 'object',
+        default: {},
+        additionalProperties: false,
+        required: ['testIdPattern'],
+        properties: {
+          testIdPattern: {
+            type: 'string',
+          },
+          testIdAttribute: {
+            type: 'string',
+            default: 'data-testid',
+          },
+        },
+      },
+    ],
+  },
+
+  create: function(context) {
+    const { options, getFilename } = context;
+    const { testIdPattern, testIdAttribute: attr } = options[0];
+
+    function getFileNameData() {
+      const splitPath = getFilename().split('/');
+      const fileNameWithExtension = splitPath.pop();
+      const parent = splitPath.pop();
+      const fileName = fileNameWithExtension.split('.').shift();
+
+      return {
+        fileName: fileName === 'index' ? parent : fileName,
+      };
+    }
+
+    function getTestIdValidator({ fileName }) {
+      return new RegExp(testIdPattern.replace(FILENAME_PLACEHOLDER, fileName));
+    }
+
+    return {
+      [`JSXIdentifier[name=${attr}]`]: node => {
+        const value =
+          node && node.parent && node.parent.value && node.parent.value.value;
+        const { fileName } = getFileNameData();
+        const regex = getTestIdValidator({ fileName });
+
+        if (value && !regex.test(value)) {
+          context.report({
+            node,
+            messageId: 'invalidTestId',
+            data: {
+              attr,
+              value,
+              regex,
+            },
+          });
+        }
+      },
+    };
+  },
+};