Add no-nested-tests rule (fixes #131) (#135)

Author: jfmengels

create-ava-rule.js

@@ -82,11 +82,9 @@ module.exports = () => {
 			}
 		},
 		CallExpression: node => {
-			if (!currentTestNode) {
-				if (isTestFunctionCall(node.callee)) {
-					// entering test function
-					currentTestNode = node;
-				}
+			if (isTestFunctionCall(node.callee)) {
+				// entering test function
+				currentTestNode = node;
 			}
 		},
 		'CallExpression:exit': node => {

docs/rules/no-nested-tests.md

@@ -0,0 +1,38 @@
+# Ensure no tests are nested
+
+Translations: [Français](https://github.com/avajs/ava-docs/blob/master/fr_FR/related/eslint-plugin-ava/docs/rules/no-nested-tests.md)
+
+In AVA, you cannot nest tests, for example, create tests inside of other tests. Doing so will lead to odd behavior.
+
+
+## Fail
+
+```js
+import test from 'ava';
+
+test('foo', t => {
+	const result = foo();
+	t.true(result.foo);
+
+	test('bar', t => {
+		t.true(result.bar);
+	});
+});
+```
+
+
+## Pass
+
+```js
+import test from 'ava';
+
+test('foo', t => {
+	const result = foo();
+	t.true(result.foo);
+});
+
+test('bar', t => {
+	const result = foo();
+	t.true(result.bar);
+});
+```

index.js

@@ -20,6 +20,7 @@ module.exports = {
 				'ava/no-identical-title': 'error',
 				'ava/no-ignored-test-files': 'error',
 				'ava/no-invalid-end': 'error',
+				'ava/no-nested-tests': 'error',
 				'ava/no-only-test': 'error',
 				'ava/no-skip-assert': 'error',
 				'ava/no-skip-test': 'error',

readme.md

@@ -38,6 +38,7 @@ Configure it in `package.json`.
 			"ava/no-identical-title": "error",
 			"ava/no-ignored-test-files": "error",
 			"ava/no-invalid-end": "error",
+			"ava/no-nested-tests": "error",
 			"ava/no-only-test": "error",
 			"ava/no-skip-assert": "error",
 			"ava/no-skip-test": "error",
@@ -71,6 +72,7 @@ The rules will only activate in test files.
 - [no-ignored-test-files](docs/rules/no-ignored-test-files.md) - Ensure no tests are written in ignored files.
 - [no-invalid-end](docs/rules/no-invalid-end.md) - Ensure `t.end()` is only called inside `test.cb()`.
 - [no-only-test](docs/rules/no-only-test.md) - Ensure no `test.only()` are present.
+- [no-nested-tests](docs/rules/no-nested-tests.md) - Ensure no tests are nested.
 - [no-skip-assert](docs/rules/no-skip-assert.md) - Ensure no assertions are skipped.
 - [no-skip-test](docs/rules/no-skip-test.md) - Ensure no tests are skipped.
 - [no-statement-after-end](docs/rules/no-statement-after-end.md) - Ensure `t.end()` is the last statement executed.

rules/no-nested-tests.js

@@ -0,0 +1,35 @@
+'use strict';
+const visitIf = require('enhance-visitors').visitIf;
+const createAvaRule = require('../create-ava-rule');
+
+const create = context => {
+	const ava = createAvaRule();
+	let nestedCount = 0;
+
+	return ava.merge({
+		'CallExpression': visitIf([
+			ava.isInTestFile,
+			ava.isTestNode
+		])(node => {
+			nestedCount++;
+			if (nestedCount >= 2) {
+				context.report({
+					node,
+					message: 'Tests should not be nested'
+				});
+			}
+		}),
+
+		'CallExpression:exit': visitIf([
+			ava.isInTestFile,
+			ava.isTestNode
+		])(() => {
+			nestedCount--;
+		})
+	});
+};
+
+module.exports = {
+	create,
+	meta: {}
+};

test/no-nested-tests.js

@@ -0,0 +1,44 @@
+import test from 'ava';
+import avaRuleTester from 'eslint-ava-rule-tester';
+import rule from '../rules/no-nested-tests';
+
+const ruleTester = avaRuleTester(test, {
+	env: {
+		es6: true
+	}
+});
+
+const header = `const test = require('ava');\n`;
+const error = {
+	ruleId: 'no-nested-tests',
+	message: 'Tests should not be nested'
+};
+
+ruleTester.run('no-nested-tests', rule, {
+	valid: [
+		header + 'test(t => {});',
+		header + 'test("title", t => {});',
+		header + 'test(t => {}); test(t => {});',
+		header + 'test("title", t => {}); test("title", t => {});',
+		header + 'test.skip(t => {});',
+		header + 'test.skip(t => {}); test.skip(t => {});',
+		header + 'test.only(t => {});',
+		header + 'test.only(t => {}); test.only(t => {});',
+		// shouldn't be triggered since it's not a test file
+		'test(t => { test(t => {}); });'
+	],
+	invalid: [
+		{
+			code: header + 'test("2", t => { test(t => {}); });',
+			errors: [error]
+		},
+		{
+			code: header + 'test(t => { test(t => {}); test(t => {}); });',
+			errors: [error, error]
+		},
+		{
+			code: header + 'test(t => { test(t => { test(t => {}); }); });',
+			errors: [error, error]
+		}
+	]
+});