diff --git a/erpnext/test_common_module.py b/erpnext/test_common_module.py
new file mode 100644
index 000000000000..b234e8aad607
--- /dev/null
+++ b/erpnext/test_common_module.py
@@ -0,0 +1,12 @@
+# Common Module - Present in Main Repository
+# This is a shared module that should be present in all forks
+
+def validate_email(email):
+    """Basic email validation"""
+    if '@' not in email or '.' not in email:
+        return False, "Invalid email format"
+    return True, "Valid email"
+
+def calculate_tax(amount, tax_rate=18):
+    """Standard tax calculation"""
+    return (amount * tax_rate) / 100