diff --git a/larkjs/lark.js b/larkjs/lark.js
index e498966..e7f7f40 100644
--- a/larkjs/lark.js
+++ b/larkjs/lark.js
@@ -306,7 +306,7 @@ function list_repeat(list, count) {
 }
 
 function isupper(a) {
-  return /^[A-Z_$]*$/.test(a);
+  return /^[^a-z]*[A-Z][^a-z]*$/.test(a);
 }
 
 function rsplit(s, delimiter, limit) {
@@ -3981,4 +3981,5 @@ module.exports = {
   Indenter,
   PythonIndenter,
   get_parser,
+  isupper,
 };
diff --git a/test/test.js b/test/test.js
index 4ffbe5f..c79b2d5 100644
--- a/test/test.js
+++ b/test/test.js
@@ -1,15 +1,19 @@
 const {TestTrees} = require("./test_trees.js");
+const {TestUtils} = require("./test_utils.js");
 
 function run_test_class(cls) {
-	describe(cls.constructor.name, function() {
+  describe(cls.constructor.name, function() {
 
-		let test = new cls();
-		test.setUp();
-		let test_names = Object.getOwnPropertyNames(cls.prototype).filter((prop) => prop.startsWith("test_"))
-		for (const name of test_names) {
-			it(name, () => {test[name]()})
-		}
-	});
+    let test = new cls();
+    if (test.setUp) {
+      test.setUp();
+    }
+    let test_names = Object.getOwnPropertyNames(cls.prototype).filter((prop) => prop.startsWith("test_"))
+    for (const name of test_names) {
+      it(name, () => {test[name]()})
+    }
+  });
 }
 
-run_test_class(TestTrees);
\ No newline at end of file
+run_test_class(TestTrees);
+run_test_class(TestUtils);
diff --git a/test/test_utils.js b/test/test_utils.js
new file mode 100644
index 0000000..5664aab
--- /dev/null
+++ b/test/test_utils.js
@@ -0,0 +1,49 @@
+const _ = require("lodash");
+const lark = require("../larkjs/lark.js");
+const assert = require('assert');
+
+const {
+  isupper,
+} = lark;
+
+class TestCase {
+  assertEqual(a, b) {
+    assert(_.isEqual(a, b), "Not equal:", a, b);
+  }
+}
+
+class TestUtils extends TestCase {
+  test_is_upper_ignore_0() {
+    this.assertEqual(isupper('__IGNORE_0'), true);
+  }
+
+  test_is_upper_hello() {
+    this.assertEqual(isupper('HELLO'), true);
+  }
+
+  test_is_upper_foo_bar() {
+    this.assertEqual(isupper('FOO_BAR'), true);
+  }
+
+  test_is_upper_foo_bar_baz() {
+    this.assertEqual(isupper('FOO-BAR BAZ'), true);
+  }
+
+  test_is_upper_hello_lowercase() {
+    this.assertEqual(isupper('Hello'), false);
+  }
+
+  test_is_upper_hell_o_uppercase() {
+    this.assertEqual(isupper('HellO'), false);
+  }
+
+  test_is_upper_single_digit() {
+    this.assertEqual(isupper('0'), false);
+  }
+
+  test_is_upper_numbers() {
+    this.assertEqual(isupper('123'), false);
+  }
+}
+
+module.exports = { TestUtils };