fix(prefer-explicit-assert): only enforce assertion when presence/absence matcher (#238)

Relates to #218

Author: skovy

docs/rules/prefer-explicit-assert.md

@@ -56,7 +56,11 @@ This rule has a few options:
   with `getBy*` queries. By default, any assertion is valid (`toBeTruthy`,
   `toBeDefined`, etc.). However, they all assert slightly different things.
   This option ensures all `getBy*` assertions are consistent and use the same
-  assertion.
+  assertion. This rule only allows defining a presence matcher
+  (`toBeInTheDocument`, `toBeTruthy`, or `toBeDefined`), but checks for both
+  presence and absence matchers (`not.toBeFalsy` and `not.toBeNull`). This means
+  other assertions such as `toHaveValue` or `toBeDisabled` will not trigger this
+  rule since these are valid uses with `getBy*`.
 
   ```js
   "testing-library/prefer-explicit-assert": ["error", {"assertion": "toBeInTheDocument"}],

lib/rules/prefer-explicit-assert.ts

@@ -1,6 +1,15 @@
 import { ESLintUtils, TSESTree } from '@typescript-eslint/experimental-utils';
-import { getDocsUrl, ALL_QUERIES_METHODS } from '../utils';
-import { isMemberExpression } from '../node-utils';
+import {
+  getDocsUrl,
+  ALL_QUERIES_METHODS,
+  PRESENCE_MATCHERS,
+  ABSENCE_MATCHERS,
+} from '../utils';
+import {
+  findClosestCallNode,
+  isIdentifier,
+  isMemberExpression,
+} from '../node-utils';
 
 export const RULE_NAME = 'prefer-explicit-assert';
 export type MessageIds =
@@ -48,6 +57,7 @@ export default ESLintUtils.RuleCreator(getDocsUrl)<Options, MessageIds>({
         properties: {
           assertion: {
             type: 'string',
+            enum: PRESENCE_MATCHERS,
           },
           customQueryNames: {
             type: 'array',
@@ -84,15 +94,29 @@ export default ESLintUtils.RuleCreator(getDocsUrl)<Options, MessageIds>({
               messageId: 'preferExplicitAssert',
             });
           } else if (assertion) {
-            const expectation = node.parent.parent.parent;
+            const expectCallNode = findClosestCallNode(node, 'expect');
+
+            const expectStatement = expectCallNode.parent as TSESTree.MemberExpression;
+            const property = expectStatement.property as TSESTree.Identifier;
+            let matcher = property.name;
+            let isNegatedMatcher = false;
 
             if (
-              expectation.type === 'MemberExpression' &&
-              expectation.property.type === 'Identifier' &&
-              expectation.property.name !== assertion
+              matcher === 'not' &&
+              isMemberExpression(expectStatement.parent) &&
+              isIdentifier(expectStatement.parent.property)
             ) {
+              isNegatedMatcher = true;
+              matcher = expectStatement.parent.property.name;
+            }
+
+            const shouldEnforceAssertion =
+              (!isNegatedMatcher && PRESENCE_MATCHERS.includes(matcher)) ||
+              (isNegatedMatcher && ABSENCE_MATCHERS.includes(matcher));
+
+            if (shouldEnforceAssertion && matcher !== assertion) {
               context.report({
-                node: expectation.property,
+                node: property,
                 messageId: 'preferExplicitAssertAssertion',
                 data: {
                   assertion,

lib/rules/prefer-presence-queries.ts

@@ -1,5 +1,5 @@
 import { ESLintUtils, TSESTree } from '@typescript-eslint/experimental-utils';
-import { getDocsUrl, ALL_QUERIES_METHODS } from '../utils';
+import { getDocsUrl, ALL_QUERIES_METHODS, PRESENCE_MATCHERS, ABSENCE_MATCHERS } from '../utils';
 import {
   findClosestCallNode,
   isMemberExpression,
@@ -13,8 +13,6 @@ type Options = [];
 const QUERIES_REGEXP = new RegExp(
   `^(get|query)(All)?(${ALL_QUERIES_METHODS.join('|')})$`
 );
-const PRESENCE_MATCHERS = ['toBeInTheDocument', 'toBeTruthy', 'toBeDefined'];
-const ABSENCE_MATCHERS = ['toBeNull', 'toBeFalsy'];
 
 function isThrowingQuery(node: TSESTree.Identifier) {
   return node.name.startsWith('get');

lib/utils.ts

@@ -65,6 +65,9 @@ const ASYNC_UTILS = [
 
 const TESTING_FRAMEWORK_SETUP_HOOKS = ['beforeEach', 'beforeAll'];
 
+const PRESENCE_MATCHERS = ['toBeInTheDocument', 'toBeTruthy', 'toBeDefined'];
+const ABSENCE_MATCHERS = ['toBeNull', 'toBeFalsy'];
+
 export {
   getDocsUrl,
   SYNC_QUERIES_VARIANTS,
@@ -77,4 +80,6 @@ export {
   ASYNC_UTILS,
   TESTING_FRAMEWORK_SETUP_HOOKS,
   LIBRARY_MODULES,
+  PRESENCE_MATCHERS,
+  ABSENCE_MATCHERS
 };

tests/lib/rules/prefer-explicit-assert.test.ts

@@ -74,6 +74,14 @@ ruleTester.run(RULE_NAME, rule, {
         },
       ],
     },
+    {
+      code: `expect(getByText('foo')).toBeEnabled()`,
+      options: [
+        {
+          assertion: 'toBeInTheDocument',
+        },
+      ],
+    },
   ],
 
   invalid: [
@@ -144,14 +152,44 @@ ruleTester.run(RULE_NAME, rule, {
       code: `expect(getByText('foo')).toBeDefined()`,
       options: [
         {
-          assertion: 'toBeInDocument',
+          assertion: 'toBeInTheDocument',
+        },
+      ],
+      errors: [
+        {
+          messageId: 'preferExplicitAssertAssertion',
+          column: 26,
+          data: { assertion: 'toBeInTheDocument' },
+        },
+      ],
+    },
+    {
+      code: `expect(getByText('foo')).not.toBeNull()`,
+      options: [
+        {
+          assertion: 'toBeInTheDocument',
+        },
+      ],
+      errors: [
+        {
+          messageId: 'preferExplicitAssertAssertion',
+          column: 26,
+          data: { assertion: 'toBeInTheDocument' },
+        },
+      ],
+    },
+    {
+      code: `expect(getByText('foo')).not.toBeFalsy()`,
+      options: [
+        {
+          assertion: 'toBeInTheDocument',
         },
       ],
       errors: [
         {
           messageId: 'preferExplicitAssertAssertion',
           column: 26,
-          data: { assertion: 'toBeInDocument' },
+          data: { assertion: 'toBeInTheDocument' },
         },
       ],
     },