feat(eslint): enable additional Jest style rules

Resolves #29

eslint/jest.js

@@ -5,6 +5,7 @@ module.exports = {
     // We may want to separate this out in future, as it's only needed when
     // using React with Testing Library.
     'plugin:testing-library/react',
+    require.resolve('./rules/jest'),
   ],
   rules: {
     // Prefer the Jest version of this rule.

eslint/rules/jest.js

@@ -0,0 +1,22 @@
+module.exports = {
+  rules: {
+    /**
+     * Disallow duplicate setup and teardown hooks.
+     *
+     * 🚫 Not fixable - https://github.com/jest-community/eslint-plugin-jest/blob/main/docs/rules/no-duplicate-hooks.md
+     */
+    'jest/no-duplicate-hooks': 'error',
+    /**
+     * Require lowercase test names.
+     *
+     * 🔧 Fixable - https://github.com/jest-community/eslint-plugin-jest/blob/main/docs/rules/prefer-lowercase-title.md
+     */
+    'jest/prefer-lowercase-title': 'warn',
+    /**
+     * Require test cases and hooks to be inside a `describe` block.
+     *
+     * 🚫 Not fixable - https://github.com/jest-community/eslint-plugin-jest/blob/main/docs/rules/require-top-level-describe.md
+     */
+    'jest/require-top-level-describe': 'error',
+  },
+};