feat(prefer-explicit-assert): add 'assertion' config option (#220)

Closes #218

Author: skovy

docs/rules/prefer-explicit-assert.md

@@ -50,7 +50,17 @@ getByNonTestingLibraryVariant('foo');
 
 ## Options
 
-This rule accepts a single options argument:
+This rule has a few options:
+
+- `assertion`: this string allows defining the preferred assertion to use
+  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.
+
+  ```js
+  "testing-library/prefer-explicit-assert": ["error", {"assertion": "toBeInTheDocument"}],
+  ```
 
 - `customQueryNames`: this array option allows to extend default Testing
   Library queries with custom ones for including them into rule

lib/rules/prefer-explicit-assert.ts

@@ -3,10 +3,13 @@ import { getDocsUrl, ALL_QUERIES_METHODS } from '../utils';
 import { isMemberExpression } from '../node-utils';
 
 export const RULE_NAME = 'prefer-explicit-assert';
-export type MessageIds = 'preferExplicitAssert';
+export type MessageIds =
+  | 'preferExplicitAssert'
+  | 'preferExplicitAssertAssertion';
 type Options = [
   {
-    customQueryNames: string[];
+    assertion?: string;
+    customQueryNames?: string[];
   }
 ];
 
@@ -34,12 +37,18 @@ export default ESLintUtils.RuleCreator(getDocsUrl)<Options, MessageIds>({
     messages: {
       preferExplicitAssert:
         'Wrap stand-alone `getBy*` query with `expect` function for better explicit assertion',
+      preferExplicitAssertAssertion:
+        '`getBy*` queries must be asserted with `{{assertion}}`',
     },
     fixable: null,
     schema: [
       {
         type: 'object',
+        additionalProperties: false,
         properties: {
+          assertion: {
+            type: 'string',
+          },
           customQueryNames: {
             type: 'array',
           },
@@ -54,7 +63,7 @@ export default ESLintUtils.RuleCreator(getDocsUrl)<Options, MessageIds>({
   ],
 
   create: function(context, [options]) {
-    const { customQueryNames } = options;
+    const { customQueryNames, assertion } = options;
     const getQueryCalls: TSESTree.Identifier[] = [];
 
     return {
@@ -74,6 +83,22 @@ export default ESLintUtils.RuleCreator(getDocsUrl)<Options, MessageIds>({
               node: queryCall,
               messageId: 'preferExplicitAssert',
             });
+          } else if (assertion) {
+            const expectation = node.parent.parent.parent;
+
+            if (
+              expectation.type === 'MemberExpression' &&
+              expectation.property.type === 'Identifier' &&
+              expectation.property.name !== assertion
+            ) {
+              context.report({
+                node: expectation.property,
+                messageId: 'preferExplicitAssertAssertion',
+                data: {
+                  assertion,
+                },
+              });
+            }
           }
         });
       },

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

@@ -66,6 +66,14 @@ ruleTester.run(RULE_NAME, rule, {
     {
       code: `queryByText("foo")`,
     },
+    {
+      code: `expect(getByText('foo')).toBeTruthy()`,
+      options: [
+        {
+          assertion: 'toBeTruthy',
+        },
+      ],
+    },
   ],
 
   invalid: [
@@ -132,5 +140,20 @@ ruleTester.run(RULE_NAME, rule, {
         },
       ],
     },
+    {
+      code: `expect(getByText('foo')).toBeDefined()`,
+      options: [
+        {
+          assertion: 'toBeInDocument',
+        },
+      ],
+      errors: [
+        {
+          messageId: 'preferExplicitAssertAssertion',
+          column: 26,
+          data: { assertion: 'toBeInDocument' },
+        },
+      ],
+    },
   ],
 });