diff --git a/Project-Euler/test/Problem003.test.js b/Project-Euler/test/Problem003.test.js
new file mode 100644
index 000000000..0f6cf4e6d
--- /dev/null
+++ b/Project-Euler/test/Problem003.test.js
@@ -0,0 +1,12 @@
+import { largestPrime } from '../Problem003.js'
+
+describe('Largest prime factor', () => {
+  test('if the number is 13195', () => {
+    expect(largestPrime(13195)).toBe(29)
+  })
+  // Project Euler Condition Check
+  test('if the number is 600851475143', () => {
+    // Default value is same as the tested value
+    expect(largestPrime()).toBe(6857)
+  })
+})