fix(valid-expect): validate async expect calls

Resolves jest-community#54
macklinu · Feb 15, 2018 · 4fa5083 · 4fa5083
1 parent e0160e5
commit 4fa5083
Show file tree

Hide file tree

Showing 2 changed files with 90 additions and 5 deletions.
diff --git a/rules/__tests__/valid-expect.test.js b/rules/__tests__/valid-expect.test.js
@@ -3,16 +3,24 @@
 const RuleTester = require('eslint').RuleTester;
 const rules = require('../..').rules;
 
-const ruleTester = new RuleTester();
+const ruleTester = new RuleTester({
+  parserOptions: {
+    ecmaVersion: 8,
+  },
+});
 
 ruleTester.run('valid-expect', rules['valid-expect'], {
   valid: [
     'expect("something").toEqual("else");',
     'expect(true).toBeDefined();',
     'expect([1, 2, 3]).toEqual([1, 2, 3]);',
     'expect(undefined).not.toBeDefined();',
-    'expect(Promise.resolve(2)).resolves.toBeDefined();',
-    'expect(Promise.reject(2)).rejects.toBeDefined();',
+    'test("foo", () => { return expect(Promise.resolve(2)).resolves.toBeDefined(); });',
+    'test("foo", async () => { await expect(Promise.reject(2)).rejects.toBeDefined(); });',
+    'test("foo", () => expect(Promise.resolve(2)).resolves.toBeDefined());',
+    'test("foo", async () => await expect(Promise.reject(2)).rejects.toBeDefined());',
+    'test("foo", async () => { expect(await Promise.resolve(2)).resolves.toBeDefined(); });',
+    'test("foo", async () => { expect(await Promise.reject(2)).rejects.toBeDefined(); });',
   ],
 
   invalid: [
@@ -131,5 +139,30 @@ ruleTester.run('valid-expect', rules['valid-expect'], {
         },
       ],
     },
+    {
+      code:
+        'test("foo", () => { expect(Promise.resolve(2)).resolves.toBeDefined(); });',
+      errors: [{ message: "Must return or await 'expect.resolves' statement" }],
+    },
+    {
+      code:
+        'test("foo", async () => { expect(Promise.resolve(2)).resolves.toBeDefined(); });',
+      errors: [{ message: "Must await 'expect.resolves' statement" }],
+    },
+    {
+      code:
+        'test("foo", () => { expect(Promise.reject(2)).rejects.toBeDefined(); });',
+      errors: [{ message: "Must return or await 'expect.rejects' statement" }],
+    },
+    {
+      code:
+        'test("foo", async () => { expect(Promise.reject(2)).rejects.toBeDefined(); });',
+      errors: [{ message: "Must await 'expect.rejects' statement" }],
+    },
+    {
+      code:
+        'test("foo", async () => expect(Promise.reject(2)).rejects.toBeDefined());',
+      errors: [{ message: 'Unexpected use of async without await' }],
+    },
   ],
 });
diff --git a/rules/valid-expect.js b/rules/valid-expect.js
@@ -5,19 +5,71 @@
  * MIT license, Tom Vincent.
  */
 
-const getDocsUrl = require('./util').getDocsUrl;
+const util = require('./util');
 
 const expectProperties = ['not', 'resolves', 'rejects'];
 
+function isResolvesOrRejectsExpression(node) {
+  if (node.expression.type !== 'CallExpression') {
+    return false;
+  }
+  const callee = node.expression.callee;
+  return (
+    callee.object &&
+    callee.object.object &&
+    callee.object.object.callee &&
+    callee.object.object.callee.name === 'expect' &&
+    callee.object.property &&
+    (callee.object.property.name === 'resolves' ||
+      callee.object.property.name === 'rejects')
+  );
+}
+
 module.exports = {
   meta: {
     docs: {
-      url: getDocsUrl('valid-expect.md'),
+      url: util.getDocsUrl('valid-expect.md'),
     },
   },
   create(context) {
+    function validateAsyncExpects(node) {
+      const callback = node.arguments[1];
+      if (callback && util.isFunction(callback)) {
+        if (callback.body.type === 'BlockStatement') {
+          callback.body.body
+            .filter(node => node.type === 'ExpressionStatement')
+            .filter(isResolvesOrRejectsExpression)
+            .forEach(node => {
+              if (
+                node.expression.callee.object.object.arguments[0].type ===
+                'AwaitExpression'
+              ) {
+                return;
+              }
+              const propertyName = node.expression.callee.object.property.name;
+              context.report({
+                node,
+                message: callback.async
+                  ? "Must await 'expect.{{ propertyName }}' statement"
+                  : "Must return or await 'expect.{{ propertyName }}' statement",
+                data: { propertyName },
+              });
+            });
+        } else if (callback.async && callback.body.type !== 'AwaitExpression') {
+          context.report({
+            node: callback.body,
+            message: 'Unexpected use of async without await',
+          });
+        }
+      }
+    }
+
     return {
       CallExpression(node) {
+        if (util.isTestCase(node)) {
+          validateAsyncExpects(node);
+        }
+
         const calleeName = node.callee.name;
 
         if (calleeName === 'expect') {