NAT-410: added a test for validate tt number

test/utils/test_helpers.py

@@ -4,7 +4,7 @@ import pytest
 
 from gso.products.product_blocks.iptrunk import IptrunkInterfaceBlock
 from gso.products.product_blocks.router import RouterVendor
-from gso.utils.helpers import available_interfaces_choices_including_current_members
+from gso.utils.helpers import available_interfaces_choices_including_current_members, validate_tt_number
 
 
 @pytest.fixture()
@@ -62,3 +62,25 @@ def test_nokia_router_with_interfaces_returns_choice(mock_router, mock_netbox_cl
     assert hasattr(result, "interface1")
     assert hasattr(result, "interface2")
     assert hasattr(result, "interface3")
+
+
+def test_tt_number(faker):
+    """Test different TT numbers"""
+
+    # Define different tt number
+    tt_number_valid1 = faker.tt_number()
+    tt_number_valid2 = faker.tt_number()
+    tt_number_valid3 = faker.tt_number()
+
+    tt_number_not_valid1 = faker.sentence()
+    err_msg = (
+        f"The given TT number: {tt_number_not_valid1} is not valid. "
+        f" A valid TT number starts with 'TT#' followed by 16 digits."
+    )
+
+    assert validate_tt_number(tt_number_valid1) == tt_number_valid1
+    assert validate_tt_number(tt_number_valid2) == tt_number_valid2
+    assert validate_tt_number(tt_number_valid3) == tt_number_valid3
+
+    with pytest.raises(ValueError, match=err_msg):
+        validate_tt_number(tt_number_not_valid1)