Added unit test for cliff impacts calculation

Author: SakshiKekre

tests/fixtures/simulation.py

@@ -61,3 +61,15 @@ def mock_dataset():
         mock_instance.file_path = SAMPLE_DATASET_FILENAME
         mock_dataset_class.from_file.return_value = mock_instance
         yield mock_instance
+
+
+@pytest.fixture
+def mock_simulation_with_cliff_vars():
+
+    mock_sim = Mock()
+    mock_sim.calculate.side_effect = lambda var: {
+        "cliff_gap": Mock(sum=Mock(return_value=100.0)),
+        "is_on_cliff": Mock(sum=Mock(return_value=40.0)),
+        "is_adult": Mock(sum=Mock(return_value=80.0)),
+    }[var]
+    return mock_sim

tests/test_simulation.py

@@ -5,11 +5,13 @@
     mock_get_default_dataset,
     mock_dataset,
     SAMPLE_DATASET_FILENAME,
+    mock_simulation_with_cliff_vars,
 )
 import sys
 from copy import deepcopy
 
 from policyengine import Simulation
+from policyengine.outputs.macro.single.calculate_single_economy import GeneralEconomyTask
 
 
 class TestSimulation:
@@ -70,3 +72,15 @@ def test__given_dataset_without_time_period__does_not_set_time_period(
                 sim._set_data_time_period(uk_sim_options_pe_dataset.data)
                 == None
             )
+
+
+    class TestCalculateCliffs:
+        def test__calculates_correct_cliff_metrics(self, mock_simulation_with_cliff_vars):
+
+            task = object.__new__(GeneralEconomyTask)
+            task.simulation = mock_simulation_with_cliff_vars
+
+            cliff_result = task.calculate_cliffs()
+
+            assert cliff_result.cliff_gap == 100.0
+            assert cliff_result.cliff_share == 0.5