Add no-incorrect-deep-equal rule (#264)

Author: MrHen

docs/rules/no-incorrect-deep-equal.md

@@ -0,0 +1,29 @@
+# Avoid using `deepEqual` with primitives
+
+The `deepEqual` and `notDeepEqual` assertions are unnecessary when comparing primitives. Use `is` or `not` instead.
+
+This rule is fixable.
+
+
+## Fail
+
+```js
+t.deepEqual(expression, 'foo');
+t.deepEqual(expression, 1);
+t.deepEqual(expression, `foo${bar}`);
+t.deepEqual(expression, null);
+t.deepEqual(expression, undefined);
+t.notDeepEqual(expression, undefined);
+```
+
+
+## Pass
+
+```js
+t.is(expression, 'foo');
+
+t.deepEqual(expression, otherExpression);
+t.deepEqual(expression, {});
+t.deepEqual(expression, []);
+t.notDeepEqual(expression, []);
+```

index.js

@@ -29,6 +29,7 @@ module.exports = {
 				'ava/no-identical-title': 'error',
 				'ava/no-ignored-test-files': 'error',
 				'ava/no-import-test-files': 'error',
+				'ava/no-incorrect-deep-equal': 'error',
 				'ava/no-inline-assertions': 'error',
 				'ava/no-invalid-end': 'error',
 				'ava/no-nested-tests': 'error',

readme.md

@@ -47,6 +47,7 @@ Configure it in `package.json`.
 			"ava/no-identical-title": "error",
 			"ava/no-ignored-test-files": "error",
 			"ava/no-import-test-files": "error",
+			"ava/no-incorrect-deep-equal": "error",
 			"ava/no-inline-assertions": "error",
 			"ava/no-invalid-end": "error",
 			"ava/no-nested-tests": "error",
@@ -86,6 +87,7 @@ The rules will only activate in test files.
 - [no-identical-title](docs/rules/no-identical-title.md) - Ensure no tests have the same title.
 - [no-ignored-test-files](docs/rules/no-ignored-test-files.md) - Ensure no tests are written in ignored files.
 - [no-import-test-files](docs/rules/no-import-test-files.md) - Ensure no test files are imported anywhere.
+- [no-incorrect-deep-equal](docs/rules/no-incorrect-deep-equal.md) - Avoid using `deepEqual` with primitives. *(fixable)*
 - [no-inline-assertions](docs/rules/no-inline-assertions.md) - Ensure assertions are not called from inline arrow functions. *(fixable)*
 - [no-invalid-end](docs/rules/no-invalid-end.md) - Ensure `t.end()` is only called inside `test.cb()`.
 - [no-nested-tests](docs/rules/no-nested-tests.md) - Ensure no tests are nested.

rules/no-incorrect-deep-equal.js

@@ -0,0 +1,93 @@
+'use strict';
+const {visitIf} = require('enhance-visitors');
+const util = require('../util');
+const createAvaRule = require('../create-ava-rule');
+
+const MESSAGE_ID = 'no-deep-equal-with-primative';
+
+const buildDeepEqualMessage = (context, node) => {
+	context.report({
+		node,
+		messageId: MESSAGE_ID,
+		data: {
+			callee: node.callee.property.name
+		},
+		fix: fixer => fixer.replaceText(node.callee.property, 'is')
+	});
+};
+
+const buildNotDeepEqualMessage = (context, node) => {
+	context.report({
+		node,
+		messageId: MESSAGE_ID,
+		data: {
+			callee: node.callee.property.name
+		},
+		fix: fixer => fixer.replaceText(node.callee.property, 'not')
+	});
+};
+
+const create = context => {
+	const ava = createAvaRule();
+
+	const callExpression = 'CallExpression';
+	const deepEqual = '[callee.property.name="deepEqual"]';
+	const notDeepEqual = '[callee.property.name="notDeepEqual"]';
+
+	const argumentsLiteral = ':matches([arguments.0.type="Literal"],[arguments.1.type="Literal"])';
+	const argumentsUndefined = ':matches([arguments.0.type="Identifier"][arguments.0.name="undefined"],[arguments.1.type="Identifier"][arguments.1.name="undefined"])';
+	const argumentsTemplate = ':matches([arguments.0.type="TemplateLiteral"],[arguments.1.type="TemplateLiteral"])';
+
+	return ava.merge({
+		[`${callExpression}${deepEqual}${argumentsLiteral}`]: visitIf([
+			ava.isInTestFile,
+			ava.isInTestNode
+		])(node => {
+			buildDeepEqualMessage(context, node);
+		}),
+		[`${callExpression}${deepEqual}${argumentsUndefined}`]: visitIf([
+			ava.isInTestFile,
+			ava.isInTestNode
+		])(node => {
+			buildDeepEqualMessage(context, node);
+		}),
+		[`${callExpression}${deepEqual}${argumentsTemplate}`]: visitIf([
+			ava.isInTestFile,
+			ava.isInTestNode
+		])(node => {
+			buildDeepEqualMessage(context, node);
+		}),
+		[`${callExpression}${notDeepEqual}${argumentsLiteral}`]: visitIf([
+			ava.isInTestFile,
+			ava.isInTestNode
+		])(node => {
+			buildNotDeepEqualMessage(context, node);
+		}),
+		[`${callExpression}${notDeepEqual}${argumentsUndefined}`]: visitIf([
+			ava.isInTestFile,
+			ava.isInTestNode
+		])(node => {
+			buildNotDeepEqualMessage(context, node);
+		}),
+		[`${callExpression}${notDeepEqual}${argumentsTemplate}`]: visitIf([
+			ava.isInTestFile,
+			ava.isInTestNode
+		])(node => {
+			buildNotDeepEqualMessage(context, node);
+		})
+	});
+};
+
+module.exports = {
+	create,
+	meta: {
+		docs: {
+			url: util.getDocsUrl(__filename)
+		},
+		fixable: true,
+		messages: {
+			[MESSAGE_ID]: 'Avoid using `{{callee}}` with literal primitives'
+		},
+		type: 'suggestion'
+	}
+};