NAT-328: add test for checking invalid site name

test/workflows/site/test_create_site.py

 import pytest
+from pydantic_forms.exceptions import FormValidationError
 
 from gso.products import ProductType
 from gso.products.product_blocks.site import SiteTier
@@ -38,3 +39,35 @@ def test_create_site(responses, faker):
         subscription.description
         == f"Site in {initial_site_data[1]['site_city']}, {initial_site_data[1]['site_country']}"
     )
+
+
+@pytest.mark.workflow
+def test_site_name_is_incorrect(responses, faker):
+    """The site name is a string with 3 upper case letter and one digit.
+    Like: AMS, LON, LON1...LON 9.
+    This test checks a invalid string for site name.
+    The validation should throw an exception in case of a invalid string.
+    """
+    invalid_site_name = "AMST10"
+    expected_exception_msg = f"Enter a valid site name similar looks like AMS, AMS1or LON9. Get: {invalid_site_name}"
+    product_id = get_product_id_by_name(ProductType.SITE)
+    initial_site_data = [
+        {"product": product_id},
+        {
+            "site_name": invalid_site_name,
+            "site_city": faker.city(),
+            "site_country": faker.country(),
+            "site_country_code": faker.country_code(),
+            "site_latitude": "-74.0060",
+            "site_longitude": "40.7128",
+            "site_bgp_community_id": faker.pyint(),
+            "site_internal_id": faker.pyint(),
+            "site_tier": SiteTier.TIER1,
+            "site_ts_address": faker.ipv4(),
+            "customer": get_customer_by_name("GÉANT")["id"],
+        },
+    ]
+
+    with pytest.raises(FormValidationError) as test_exception:
+        result, process, step_log = run_workflow("create_site", initial_site_data)
+        assert str(test_exception.value) == expected_exception_msg