Create-Add files to greedy_method directory (#2082)

* Add Greedy Method Approach

* Update Filename

* Update Variable and Links

* Fixed flake8 bugs

* Update unittest filename

* Update unittest filename

* Final unittest filename update

* Pythonic Code formatting

* flake8 fixes

* lowercase function name

* Add zip function

* Add zip function

* params lowercase

* Travis CI fixes

* Update and rename knapsack_problem.py to knapsack.py

* Update test_knapsack.py

* Fix bugs

* Rename knapsack.py to greedy_knapsack.py

* Update test_knapsack.py

Co-authored-by: Christian Clauss <cclauss@me.com>

greedy_method/test_knapsack.py

@@ -0,0 +1,74 @@
+import unittest
+import greedy_knapsack as kp
+
+
+class TestClass(unittest.TestCase):
+    """
+    Test cases for knapsack
+    """
+
+    def test_sorted(self):
+        """
+        kp.calc_profit takes the required argument (profit, weight, max_weight)
+        and returns whether the answer matches to the expected ones
+        """
+        profit = [10, 20, 30, 40, 50, 60]
+        weight = [2, 4, 6, 8, 10, 12]
+        max_weight = 100
+        self.assertEqual(kp.calc_profit(profit, weight, max_weight), 210)
+
+    def test_negative_max_weight(self):
+        """
+        Returns ValueError for any negative max_weight value
+        :return: ValueError
+        """
+        # profit = [10, 20, 30, 40, 50, 60]
+        # weight = [2, 4, 6, 8, 10, 12]
+        # max_weight = -15
+        self.assertRaisesRegex(ValueError, "max_weight must greater than zero.")
+
+    def test_negative_profit_value(self):
+        """
+        Returns ValueError for any negative profit value in the list
+        :return: ValueError
+        """
+        # profit = [10, -20, 30, 40, 50, 60]
+        # weight = [2, 4, 6, 8, 10, 12]
+        # max_weight = 15
+        self.assertRaisesRegex(
+            ValueError, "Weight can not be negative.",
+        )
+
+    def test_negative_weight_value(self):
+        """
+        Returns ValueError for any negative weight value in the list
+        :return: ValueError
+        """
+        # profit = [10, 20, 30, 40, 50, 60]
+        # weight = [2, -4, 6, -8, 10, 12]
+        # max_weight = 15
+        self.assertRaisesRegex(ValueError, "Profit can not be negative.")
+
+    def test_null_max_weight(self):
+        """
+        Returns ValueError for any zero max_weight value
+        :return: ValueError
+        """
+        # profit = [10, 20, 30, 40, 50, 60]
+        # weight = [2, 4, 6, 8, 10, 12]
+        # max_weight = null
+        self.assertRaisesRegex(ValueError, "max_weight must greater than zero.")
+
+    def test_unequal_list_length(self):
+        """
+        Returns IndexError if length of lists (profit and weight) are unequal.
+        :return: IndexError
+        """
+        # profit = [10, 20, 30, 40, 50]
+        # weight = [2, 4, 6, 8, 10, 12]
+        # max_weight = 100
+        self.assertRaisesRegex(IndexError, "The length of profit and weight must be same.")
+
+
+if __name__ == "__main__":
+    unittest.main()