test: add tests for new language features

PR-URL: https://github.com/nodejs/node/pull/27400
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

test/parallel/test-assert.js

@@ -631,13 +631,13 @@ common.expectsError(
   }
 );
 common.expectsError(
-  () => assert(typeof 123 === 'string'),
+  () => assert(typeof 123n === 'string'),
   {
     code: 'ERR_ASSERTION',
     type: assert.AssertionError,
     generatedMessage: true,
     message: 'The expression evaluated to a falsy value:\n\n  ' +
-             "assert(typeof 123 === 'string')\n"
+             "assert(typeof 123n === 'string')\n"
   }
 );
 

test/parallel/test-repl.js

@@ -328,6 +328,21 @@ const errorTests = [
     send: '1 }',
     expect: '{ a: 1 }'
   },
+  // Multiline class with private member.
+  {
+    send: 'class Foo { #private = true ',
+    expect: '... '
+  },
+  // Class field with bigint.
+  {
+    send: 'num = 123456789n',
+    expect: '... '
+  },
+  // Static class features.
+  {
+    send: 'static foo = "bar" }',
+    expect: 'undefined'
+  },
   // Multiline anonymous function with comment
   {
     send: '(function() {',
@@ -338,12 +353,12 @@ const errorTests = [
     expect: '... '
   },
   {
-    send: 'return 1;',
+    send: 'return 1n;',
     expect: '... '
   },
   {
     send: '})()',
-    expect: '1'
+    expect: '1n'
   },
   // Multiline function call
   {