Repository: avajs/eslint-plugin-ava (js)

Issue:
Add general rule tests
Like: https://github.com/sindresorhus/eslint-plugin-unicorn/blob/master/test/package.js Can probably just borrow those directly.

Pull request description:
Add tests to enforce some rule guidelines
Fixes #242

Patch:
diff --git a/readme.md b/readme.md
index 4851b52..5b382da 100644
--- a/readme.md
+++ b/readme.md
@@ -59,8 +59,8 @@ Configure it in `package.json`.
 			"ava/prefer-power-assert": "off",
 			"ava/test-ended": "error",
 			"ava/test-title": "error",
-			"ava/use-t-well": "error",
 			"ava/use-t": "error",
+			"ava/use-t-well": "error",
 			"ava/use-test": "error",
 			"ava/use-true-false": "error"
 		}
@@ -94,8 +94,8 @@ The rules will only activate in test files.
 - [prefer-power-assert](docs/rules/prefer-power-assert.md) - Allow only use of the asserts that have no [power-assert](https://github.com/power-assert-js/power-assert) alternative.
 - [test-ended](docs/rules/test-ended.md) - Ensure callback tests are explicitly ended.
 - [test-title](docs/rules/test-title.md) - Ensure tests have a title.
-- [use-t-well](docs/rules/use-t-well.md) - Prevent the incorrect use of `t`. *(partly fixable)*
 - [use-t](docs/rules/use-t.md) - Ensure test functions use `t` as their parameter.
+- [use-t-well](docs/rules/use-t-well.md) - Prevent the incorrect use of `t`. *(partly fixable)*
 - [use-test](docs/rules/use-test.md) - Ensure that AVA is imported with `test` as the variable name.
 - [use-true-false](docs/rules/use-true-false.md) - Ensure that `t.true()`/`t.false()` are used instead of `t.truthy()`/`t.falsy()`.
 


Test patch:
diff --git a/test/package.js b/test/package.js
index d8f67db..c3e6faf 100644
--- a/test/package.js
+++ b/test/package.js
@@ -4,20 +4,94 @@ import test from 'ava';
 import pify from 'pify';
 import index from '..';
 
-test('Every rule is defined in index file', async t => {
-	const ruleDir = path.resolve(__dirname, '../rules');
-	const files = await pify(fs.readdir)(ruleDir);
+let ruleFiles;
 
-	const rules = files.filter(file =>
-		file.indexOf('.js') === file.length - 3 &&
-		!fs.readFileSync(path.join(ruleDir, file), 'utf8').includes('deprecated: true'));
+test.before(async () => {
+	const files = await pify(fs.readdir)('rules');
+	ruleFiles = files.filter(file => path.extname(file) === '.js');
+});
+
+const testSorted = (t, actualOrder, sourceName) => {
+	const sortedOrder = actualOrder.slice(0).sort();
+
+	for (const [wantedIndex, name] of sortedOrder.entries()) {
+		const actualIndex = actualOrder.indexOf(name);
+		const whereMessage = (wantedIndex === 0) ? '' : `, after '${sortedOrder[wantedIndex - 1]}'`;
+		t.is(actualIndex, wantedIndex, `${sourceName} should be alphabetically sorted, '${name}' should be placed at index ${wantedIndex}${whereMessage}`);
+	}
+};
+
+test('Every rule is defined in index file in alphabetical order', t => {
+	for (const file of ruleFiles) {
+		const name = path.basename(file, '.js');
+
+		// Ignoring tests for no-ignored-test-files
+		if (name === 'no-ignored-test-files') {
+			return;
+		}
 
-	for (const file of rules) {
-		const name = file.slice(0, -3);
 		t.truthy(index.rules[name], `'${name}' is not exported in 'index.js'`);
 		t.truthy(index.configs.recommended.rules[`ava/${name}`], `'${name}' is not set in the recommended config`);
+		t.truthy(fs.existsSync(path.join('docs/rules', `${name}.md`)), `There is no documentation for '${name}'`);
+		t.truthy(fs.existsSync(path.join('test', file)), `There are no tests for '${name}'`);
 	}
 
-	t.is(Object.keys(index.configs.recommended.rules).length, rules.length,
+	t.is(Object.keys(index.rules).length, ruleFiles.length,
+		'There are more exported rules than rule files.');
+	t.is(Object.keys(index.configs.recommended.rules).length, ruleFiles.length,
 		'There are more exported rules in the recommended config than rule files.');
+
+	testSorted(t, Object.keys(index.configs.recommended.rules), 'configs.recommended.rules');
+});
+
+test('Every rule is defined in readme.md usage and list of rules in alphabetical order', async t => {
+	const readme = await pify(fs.readFile)('readme.md', 'utf8');
+	let usageRules;
+	try {
+		const usageRulesMatch = /## Usage.*?"rules": (\{.*?\})/ms.exec(readme);
+		t.truthy(usageRulesMatch, 'List of rules should be defined in readme.md ## Usage');
+		usageRules = JSON.parse(usageRulesMatch[1]);
+	} catch (_) {}
+
+	t.truthy(usageRules, 'List of rules should be defined in readme.md ## Usage and be valid JSON');
+
+	const rulesMatch = /## Rules(.*?)## Recommended config/ms.exec(readme);
+	t.truthy(rulesMatch, 'List of rules should be defined in readme.md in ## Rules before ## Recommended config');
+	const rulesText = rulesMatch[1];
+	const re = /- \[(.*?)\]\((.*?)\) - (.*)\n/gm;
+	const rules = [];
+	let match;
+	do {
+		match = re.exec(rulesText);
+		if (match) {
+			t.is(match[2], `docs/rules/${match[1]}.md`, `${match[1]} link to docs should be correct`);
+			t.true(match[3].trim().length > 0, `${match[1]} should have description in readme.md ## Rules`);
+			rules.push(match[1]);
+		}
+	} while (match);
+
+	for (const file of ruleFiles) {
+		const name = path.basename(file, '.js');
+		t.truthy(usageRules[`ava/${name}`], `'${name}' is not described in the readme.md ## Usage`);
+		t.truthy(rules.includes(name), `'${name}' is not described in the readme.md ## Rules`);
+	}
+
+	t.is(Object.keys(usageRules).length, ruleFiles.length, 'There are more rules in readme.md ## Usage than rule files.');
+	t.is(Object.keys(rules).length, ruleFiles.length, 'There are more rules in readme.md ## Rules than rule files.');
+
+	testSorted(t, Object.keys(usageRules), 'readme.md ## Usage rules');
+	testSorted(t, rules, 'readme.md ## Rules');
+});
+
+test('Every rule has valid meta.type', t => {
+	const validTypes = ['problem', 'suggestion', 'layout'];
+
+	for (const file of ruleFiles) {
+		const name = path.basename(file, '.js');
+		const rule = index.rules[name];
+
+		t.true(rule.meta !== null && rule.meta !== undefined, `${name} has no meta`);
+		t.is(typeof rule.meta.type, 'string', `${name} meta.type is not string`);
+		t.true(validTypes.includes(rule.meta.type), `${name} meta.type is not one of [${validTypes.join(', ')}]`);
+	}
 });