diff --git a/resources/knapsack.py b/resources/knapsack.py
index e1b694d238a19a210c8356d77f1e85d11905edf6..ea50f72da27e9127e0ab177dd7d844c094e025c7 100644
--- a/resources/knapsack.py
+++ b/resources/knapsack.py
@@ -35,6 +35,31 @@ class FractionalKnapsackAlgorithm():
Sets group of items to choose from.
:param item_set: Set of items, essentially in JSON format.
"""
+ # First validate item set.
+ if self.validate_item_set(item_set):
+ # Validation passed. Set values.
+ self._item_set_ = item_set
+ self._items_populated_ = True
+
+ def validate_item_set(self, item_set):
+ """
+ Runs the internal "validate_item_set" method.
+ On error, returns False. Otherwise returns True.
+ :param item_set: Potential "item set" to validate.
+ :return: True if validation passes. False otherwise.
+ """
+ try:
+ self._validate_item_set(item_set)
+ return True
+ except (TypeError, KeyError, ValueError):
+ return False
+
+ def _validate_item_set(self, item_set):
+ """
+ Validates given item set to make sure it's the format we expect.
+ If validation fails, it will raise an error.
+ :param item_set: Potential "item set" to validate.
+ """
# Check that value is List type.
if not isinstance(item_set, list):
raise TypeError('Arg must be array of dict objects.')
@@ -45,14 +70,20 @@ class FractionalKnapsackAlgorithm():
if not isinstance(item, dict):
raise TypeError('Arg must be array of dict objects.')
+ # Check that 'benefit' key exists.
if 'benefit' not in item.keys():
raise KeyError('Key "benefit" must be present in all items.')
+ # Check that 'cost' key exists.
if 'cost' not in item.keys():
raise KeyError('Key "cost" must be present in all items.')
- self._item_set_ = item_set
- self._items_populated_ = True
+ # Check that 'benefit' key is parsable as int.
+ int(str(item['benefit']).strip())
+
+ # Check that 'cost' key is parsable as int.
+ int(str(item['cost']).strip())
+
def set_max_weight(self, max_weight):
"""
diff --git a/tests/resources/knapsack.py b/tests/resources/knapsack.py
index 08fc61a9ed6ed9110a36fa00a083cc36fd9f4b9e..656acc8bb4ae880094180f4003083b4c6a883641 100644
--- a/tests/resources/knapsack.py
+++ b/tests/resources/knapsack.py
@@ -65,30 +65,81 @@ class TestKnapsack(unittest.TestCase):
self.assertFalse(self.knapsack._weight_populated_)
def test_set_item_set_success(self):
- # Test with set 1.
+ # Test success with set 1.
self.knapsack.set_item_set(self.item_set_1)
self.assertEqual(self.knapsack._item_set_, self.item_set_1)
self.assertTrue(self.knapsack._items_populated_)
- # Test with set 2.
+ # Test success with set 2.
self.knapsack.set_item_set(self.item_set_2)
self.assertEqual(self.knapsack._item_set_, self.item_set_2)
self.assertTrue(self.knapsack._items_populated_)
def test_set_item_set_failure(self):
+ with self.subTest('Arg is not array of dicts'):
+ # Passed None.
+ self.knapsack.set_item_set(None)
+ self.assertEqual(self.knapsack._item_set_, [])
+ self.assertFalse(self.knapsack._items_populated_)
+
+ # Passed array with no dict items.
+ self.knapsack.set_item_set([1, 2, 3])
+ self.assertEqual(self.knapsack._item_set_, [])
+ self.assertFalse(self.knapsack._items_populated_)
+
+ with self.subTest('Dict item must have "benefit" and "cost" keys.'):
+ # Passed dict item missing "cost" key.
+ self.knapsack.set_item_set([{'benefit': 1}])
+ self.assertEqual(self.knapsack._item_set_, [])
+ self.assertFalse(self.knapsack._items_populated_)
+
+ # Passed dict item missing "benefit" key.
+ self.knapsack.set_item_set([{'cost': 1}])
+ self.assertEqual(self.knapsack._item_set_, [])
+ self.assertFalse(self.knapsack._items_populated_)
+
+ with self.subTest('Item values must be parsable as integers.'):
+ # Passed bad value for "benefit" key.
+ self.knapsack.set_item_set([{'benefit': 'a', 'cost': 1}])
+ self.assertEqual(self.knapsack._item_set_, [])
+ self.assertFalse(self.knapsack._items_populated_)
+
+ # Passed bad value for "cost" key.
+ self.knapsack.set_item_set([{'benefit': 1, 'cost': 'a'}])
+ self.assertEqual(self.knapsack._item_set_, [])
+ self.assertFalse(self.knapsack._items_populated_)
+
+ def test_validate_item_set(self):
+ # Test success with set 1.
+ self.assertTrue(self.knapsack.validate_item_set(self.item_set_1))
+
+ # Test success with set 2.
+ self.assertTrue(self.knapsack.validate_item_set(self.item_set_2))
+
+ # Test failure.
+ self.assertFalse(self.knapsack.validate_item_set(None))
+
+ def test__validate_item_set_failure(self):
with self.subTest('Arg is not array of dicts'):
with self.assertRaises(TypeError):
- self.knapsack.set_item_set(None)
+ self.knapsack._validate_item_set(None)
with self.assertRaises(TypeError):
- self.knapsack.set_item_set([1, 2, 3])
+ self.knapsack._validate_item_set([1, 2, 3])
with self.subTest('Dict item must have "benefit" and "cost" keys.'):
with self.assertRaises(KeyError):
- self.knapsack.set_item_set([{'benefit': 1}])
+ self.knapsack._validate_item_set([{'benefit': 1}])
with self.assertRaises(KeyError):
- self.knapsack.set_item_set([{'cost': 1}])
+ self.knapsack._validate_item_set([{'cost': 1}])
+
+ with self.subTest('Item values must be parsable as integers.'):
+ with self.assertRaises(ValueError):
+ self.knapsack._validate_item_set([{'benefit': 'a', 'cost': 1}])
+
+ with self.assertRaises(ValueError):
+ self.knapsack._validate_item_set([{'benefit': 1, 'cost': 'a'}])
def test_set_max_weight_success(self):
self.knapsack.set_max_weight(1)