Removed one more utils reference in the README and fixed directory name

Signed-off-by: Carlo Costino <carlo.costino@gsa.gov>

tests/notifications_utils/test_international_billing_rates.py

@@ -0,0 +1,50 @@
+import pytest
+
+from notifications_utils.international_billing_rates import (
+    COUNTRY_PREFIXES,
+    INTERNATIONAL_BILLING_RATES,
+)
+from notifications_utils.recipients import use_numeric_sender
+
+
+def test_international_billing_rates_exists():
+    assert INTERNATIONAL_BILLING_RATES["1"]["names"][0] == "Canada"
+
+
+@pytest.mark.parametrize(
+    "country_prefix, values", sorted(INTERNATIONAL_BILLING_RATES.items())
+)
+def test_international_billing_rates_are_in_correct_format(country_prefix, values):
+    assert isinstance(country_prefix, str)
+    # we don't want the prefixes to have + at the beginning for instance
+    assert country_prefix.isdigit()
+
+    assert set(values.keys()) == {"attributes", "billable_units", "names"}
+
+    assert isinstance(values["billable_units"], int)
+    assert 1 <= values["billable_units"] <= 3
+
+    assert isinstance(values["names"], list)
+    assert all(isinstance(country, str) for country in values["names"])
+
+    assert isinstance(values["attributes"], dict)
+    assert values["attributes"]["dlr"] is None or isinstance(
+        values["attributes"]["dlr"], str
+    )
+
+
+def test_country_codes():
+    assert len(COUNTRY_PREFIXES) == 214
+
+
+@pytest.mark.parametrize(
+    "number, expected",
+    [
+        ("+48123654789", False),  # Poland alpha: Yes
+        ("+1-403-123-5687", True),  # Canada alpha: No
+        ("+40123548897", False),  # Romania alpha: REG
+        ("+60123451345", True),
+    ],
+)  # Malaysia alpha: NO
+def test_use_numeric_sender(number, expected):
+    assert use_numeric_sender(number) == expected