Validate PoP dates against contract dates config on the backend

tests/forms/test_task_order.py

@@ -1,4 +1,6 @@
 import datetime
+from dateutil.relativedelta import relativedelta
+from flask import current_app as app
 
 from atst.forms.task_order import CLINForm
 from atst.models import JEDICLINType
@@ -30,3 +32,34 @@ def test_clin_form_start_date_before_end_date():
     )
     valid_clin_form = CLINForm(obj=valid_clin)
     assert valid_clin_form.validate()
+
+
+def test_clin_form_pop_dates_within_contract_dates():
+    CONTRACT_START_DATE = datetime.datetime.strptime(
+        app.config.get("CONTRACT_START_DATE"), "%Y-%m-%d"
+    ).date()
+    CONTRACT_END_DATE = datetime.datetime.strptime(
+        app.config.get("CONTRACT_END_DATE"), "%Y-%m-%d"
+    ).date()
+
+    invalid_start = CONTRACT_START_DATE - relativedelta(months=1)
+    invalid_end = CONTRACT_END_DATE + relativedelta(months=1)
+    invalid_clin = factories.CLINFactory.create(
+        start_date=invalid_start, end_date=invalid_end
+    )
+    clin_form = CLINForm(obj=invalid_clin)
+    assert not clin_form.validate()
+    assert (
+        "PoP start date must be on or after {}.".format(CONTRACT_START_DATE)
+    ) in clin_form.start_date.errors
+    assert (
+        "PoP end date must be before or on {}.".format(CONTRACT_END_DATE)
+    ) in clin_form.end_date.errors
+
+    valid_start = CONTRACT_START_DATE + relativedelta(months=1)
+    valid_end = CONTRACT_END_DATE - relativedelta(months=1)
+    valid_clin = factories.CLINFactory.create(
+        start_date=valid_start, end_date=valid_end
+    )
+    valid_clin_form = CLINForm(obj=valid_clin)
+    assert valid_clin_form.validate()