[Tests] strip 'type:' from RuleTester errors on eslint >= 10 via helper

Instead of removing `type:` from each test file, wrapping the invalid test cases in `tests/helpers/ruleTester.js` to strip `type` when the running ESLint is >= 10. On older versions the function does nothing, keeping all `type:` assertions intact.

Author: captaindonald

tests/helpers/ruleTester.js

@@ -47,6 +47,24 @@ function convertToFlat(item, plugins) {
   return newItem;
 }
 
+const stripTypeOnEslint10 = semver.major(eslintPkg.version) >= 10
+  ? (test) => {
+      if (!test || typeof test !== 'object' || !Array.isArray(test.errors)) {
+        return test;
+      }
+      return Object.assign({}, test, {
+        errors: test.errors.map((err) => {
+          if (!err || typeof err !== 'object' || !('type' in err)) {
+            return err;
+          }
+          const next = Object.assign({}, err);
+          delete next.type;
+          return next;
+        }),
+      });
+    }
+  : (test) => test;
+
 let RuleTester = ESLintRuleTester;
 
 if (semver.major(eslintPkg.version) >= 9) {
@@ -98,7 +116,9 @@ if (semver.major(eslintPkg.version) >= 9) {
     run(ruleName, rule, tests) {
       const newTests = {
         valid: tests.valid.map((test) => convertToFlat(test, this[PLUGINS])),
-        invalid: tests.invalid.map((test) => convertToFlat(test, this[PLUGINS])),
+        invalid: tests.invalid
+          .map(stripTypeOnEslint10)
+          .map((test) => convertToFlat(test, this[PLUGINS])),
       };
 
       super.run(ruleName, rule, newTests);