diff --git a/commitlint/tests/testHelpers.ts b/commitlint/tests/testHelpers.ts
index 766c17e5..c1809f76 100644
--- a/commitlint/tests/testHelpers.ts
+++ b/commitlint/tests/testHelpers.ts
@@ -91,7 +91,7 @@ test("testing TypeHelpers.IsInstanceOf", () => {
 
 test("testing TypeHelpers.IsInstanceOf exceptions", () => {
     let strNull = null;
-    expect(() => TypeHelpers.IsInstanceOf(strNull, String)).toThrowError("null");
+    expect(() => TypeHelpers.IsInstanceOf(strNull, String)).toThrowError("Invalid");
 });
 
 export function runCommitLintOnMsg(inputMsg: string) {