Merge pull request #7 from SaladFork/feature/add-no-unnecessary-waiting-rule

Add `no-unnecessary-waiting` rule

Author: chrisbreiding

README.md

@@ -46,6 +46,7 @@ rules which have a wrench (🔧) below.
 |    | Rule ID | Description |
 |:---|:--------|:------------|
 | ✅ | [no-assigning-return-values](./docs/rules/no-assigning-return-values.md) | Prevent assigning return values of cy calls |
+| ✅ | [no-unnecessary-waiting](./docs/rules/no-unnecessary-waiting.md) | Prevent waiting for arbitrary time periods |
 
 ## Chai and `no-unused-expressions`
 

docs/rules/no-unnecessary-waiting.md

@@ -0,0 +1,3 @@
+## No Assigning Return Values
+
+See [the Cypress Best Practices guide](https://docs.cypress.io/guides/references/best-practices.html#Unnecessary-Waiting).

index.js

@@ -3,6 +3,7 @@ const globals = require('globals')
 module.exports = {
   rules: {
     'no-assigning-return-values': require('./lib/rules/no-assigning-return-values'),
+    'no-unnecessary-waiting': require('./lib/rules/no-unnecessary-waiting'),
   },
   configs: {
     recommended: require('./lib/config/recommended'),

lib/config/recommended.js

@@ -3,6 +3,7 @@
 module.exports = {
   plugins: ['cypress'],
   rules: {
-    'cypress/no-assigning-return-values': 'error'
+    'cypress/no-assigning-return-values': 'error',
+    'cypress/no-unnecessary-waiting': 'error'
   }
 };

lib/rules/no-unnecessary-waiting.js

@@ -0,0 +1,44 @@
+/**
+ * @fileoverview Prevent waiting for arbitrary time periods
+ * @author Elad Shahar
+ */
+
+'use strict';
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Prevent waiting for arbitrary time periods',
+      category: 'Possible Errors',
+      recommended: true,
+      url: 'https://docs.cypress.io/guides/references/best-practices.html#Unnecessary-Waiting'
+    },
+    schema: [],
+    messages: {
+      unexpected: 'Do not wait for arbitrary time periods'
+    }
+  },
+  create(context) {
+    return {
+      CallExpression(node) {
+        if (isCallingCyWait(node) && isNumberArgument(node)) {
+          context.report({ node, messageId: 'unexpected' });
+        }
+      }
+    };
+  }
+};
+
+function isCallingCyWait(node) {
+  return node.callee.type === 'MemberExpression' &&
+         node.callee.object.type === 'Identifier' &&
+         node.callee.object.name === 'cy' &&
+         node.callee.property.type === 'Identifier' &&
+         node.callee.property.name === 'wait';
+}
+
+function isNumberArgument(node) {
+  return node.arguments.length > 0 &&
+         node.arguments[0].type === 'Literal' &&
+         typeof(node.arguments[0].value) === 'number';
+}

tests/lib/rules/no-unnecessary-waiting.js

@@ -0,0 +1,28 @@
+"use strict";
+
+const rule = require('../../../lib/rules/no-unnecessary-waiting');
+const RuleTester = require('eslint').RuleTester;
+
+const ruleTester = new RuleTester();
+
+const errors = [{ messageId: 'unexpected' }];
+const parserOptions = { ecmaVersion: 6 };
+
+ruleTester.run('no-unnecessary-waiting', rule, {
+  valid: [
+    { code: 'cy.wait("@someRequest")', parserOptions },
+    { code: 'cy.wait("@someRequest", { log: false })', parserOptions },
+    { code: 'cy.wait("@someRequest").then((xhr) => xhr)', parserOptions },
+    { code: 'cy.wait(["@someRequest", "@anotherRequest"])', parserOptions },
+
+    { code: 'cy.clock(5000)', parserOptions},
+    { code: 'cy.scrollTo(0, 10)', parserOptions },
+    { code: 'cy.tick(500)', parserOptions }
+  ],
+
+  invalid: [
+    { code: 'cy.wait(0)', parserOptions, errors },
+    { code: 'cy.wait(100)', parserOptions, errors },
+    { code: 'cy.wait(5000)', parserOptions, errors }
+  ]
+});