diff --git a/extensions/typescript-language-features/src/test/functionCallSnippet.test.ts b/extensions/typescript-language-features/src/test/functionCallSnippet.test.ts
index 9cedd07e746..f5da5c7ca19 100644
--- a/extensions/typescript-language-features/src/test/functionCallSnippet.test.ts
+++ b/extensions/typescript-language-features/src/test/functionCallSnippet.test.ts
@@ -5,10 +5,11 @@
 
 import * as assert from 'assert';
 import 'mocha';
+import * as vscode from 'vscode';
 import { snippetForFunctionCall } from '../features/completions';
 
 suite('typescript function call snippets', () => {
-	test('Should use label as name if no display parts are provided', async () => {
+	test('Should use label as function name', async () => {
 		assert.strictEqual(
 			snippetForFunctionCall(
 				{ label: 'abc', },
@@ -17,7 +18,7 @@ suite('typescript function call snippets', () => {
 			'abc()$0');
 	});
 
-	test('Should use insertText to override function name if no display parts are provided', async () => {
+	test('Should use insertText string to override function name', async () => {
 		assert.strictEqual(
 			snippetForFunctionCall(
 				{ label: 'abc', insertText: 'def' },
@@ -25,4 +26,22 @@ suite('typescript function call snippets', () => {
 			).value,
 			'def()$0');
 	});
+
+	test('Should return insertText as-is if it is already a snippet', async () => {
+		assert.strictEqual(
+			snippetForFunctionCall(
+				{ label: 'abc', insertText: new vscode.SnippetString('bla()$0') },
+				[]
+			).value,
+			'bla()$0');
+	});
+
+	test('Should return insertText as-is if it is already a snippet', async () => {
+		assert.strictEqual(
+			snippetForFunctionCall(
+				{ label: 'abc', insertText: new vscode.SnippetString('bla()$0') },
+				[]
+			).value,
+			'bla()$0');
+	});
 });