tools: auto fix custom eslint rule

1. Extends tests
2. Refactors code
3. Adds fixer

Refs: #16636

PR-URL: #16652
Refs: #16636
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

test/parallel/test-eslint-prefer-assert-methods.js

@@ -9,31 +9,46 @@ const rule = require('../../tools/eslint-rules/prefer-assert-methods');
 
 new RuleTester().run('prefer-assert-methods', rule, {
   valid: [
-    'assert.strictEqual(foo, bar)',
-    'assert(foo === bar && baz)'
+    'assert.strictEqual(foo, bar);',
+    'assert(foo === bar && baz);',
+    'assert.notStrictEqual(foo, bar);',
+    'assert(foo !== bar && baz);',
+    'assert.equal(foo, bar);',
+    'assert(foo == bar && baz);',
+    'assert.notEqual(foo, bar);',
+    'assert(foo != bar && baz);',
+    'assert.ok(foo);',
+    'assert.ok(foo != bar);',
+    'assert.ok(foo === bar && baz);'
   ],
   invalid: [
     {
-      code: 'assert(foo == bar)',
-      errors: [{ message: "'assert.equal' should be used instead of '=='" }]
+      code: 'assert(foo == bar);',
+      errors: [{
+        message: "'assert.equal' should be used instead of '=='"
+      }],
+      output: 'assert.equal(foo, bar);'
     },
     {
-      code: 'assert(foo === bar)',
+      code: 'assert(foo === bar);',
       errors: [{
         message: "'assert.strictEqual' should be used instead of '==='"
-      }]
+      }],
+      output: 'assert.strictEqual(foo, bar);'
     },
     {
-      code: 'assert(foo != bar)',
+      code: 'assert(foo != bar);',
       errors: [{
         message: "'assert.notEqual' should be used instead of '!='"
-      }]
+      }],
+      output: 'assert.notEqual(foo, bar);'
     },
     {
-      code: 'assert(foo !== bar)',
+      code: 'assert(foo !== bar);',
       errors: [{
         message: "'assert.notStrictEqual' should be used instead of '!=='"
-      }]
-    },
+      }],
+      output: 'assert.notStrictEqual(foo, bar);'
+    }
   ]
 });

tools/eslint-rules/prefer-assert-methods.js

@@ -1,3 +1,7 @@
+/**
+ * @fileoverview Prohibit the use of assert operators ( ===, !==, ==, != )
+ */
+
 'use strict';
 
 const astSelector = 'ExpressionStatement[expression.type="CallExpression"]' +
@@ -21,7 +25,19 @@ module.exports = function(context) {
       const arg = node.expression.arguments[0];
       const assertMethod = preferedAssertMethod[arg.operator];
       if (assertMethod) {
-        context.report(node, parseError(assertMethod, arg.operator));
+        context.report({
+          node,
+          message: parseError(assertMethod, arg.operator),
+          fix: (fixer) => {
+            const sourceCode = context.getSourceCode();
+            const left = sourceCode.getText(arg.left);
+            const right = sourceCode.getText(arg.right);
+            return fixer.replaceText(
+              node,
+              `assert.${assertMethod}(${left}, ${right});`
+            );
+          }
+        });
       }
     }
   };