finish the exercise

python/currency-exchange/exchange.py

@@ -6,7 +6,7 @@ def exchange_money(budget, exchange_rate):
     :return: float - exchanged value of the foreign currency you can receive.
     """
 
-    pass
+    return budget / exchange_rate
 
 
 def get_change(budget, exchanging_value):
@@ -17,7 +17,7 @@ def get_change(budget, exchanging_value):
     :return: float - amount left of your starting currency after exchanging.
     """
 
-    pass
+    return budget - exchanging_value
 
 
 def get_value_of_bills(denomination, number_of_bills):
@@ -28,7 +28,7 @@ def get_value_of_bills(denomination, number_of_bills):
     :return: int - total value of bills you now have.
     """
 
-    pass
+    return denomination * number_of_bills
 
 
 def get_number_of_bills(budget, denomination):
@@ -39,7 +39,7 @@ def get_number_of_bills(budget, denomination):
     :return: int - number of bills after exchanging all your money.
     """
 
-    pass
+    return int(budget) // int(denomination)
 
 
 def exchangeable_value(budget, exchange_rate, spread, denomination):
@@ -52,7 +52,12 @@ def exchangeable_value(budget, exchange_rate, spread, denomination):
     :return: int - maximum value you can get.
     """
 
-    pass
+    percentage = spread / 100
+    real_exchange_rate = exchange_rate + exchange_rate * percentage
+    number_of_bills = get_number_of_bills(
+        budget / real_exchange_rate, denomination)
+
+    return number_of_bills * denomination
 
 
 def non_exchangeable_value(budget, exchange_rate, spread, denomination):
@@ -65,4 +70,11 @@ def non_exchangeable_value(budget, exchange_rate, spread, denomination):
     :return: int non-exchangeable value.
     """
 
-    pass
+    percentage = spread / 100
+    real_exchange_rate = exchange_rate + exchange_rate * percentage
+    number_of_bills = get_number_of_bills(
+        budget / real_exchange_rate, denomination)
+
+    foreign = number_of_bills * denomination
+
+    return int(budget / real_exchange_rate - foreign)

python/currency-exchange/exchange_test.py

@@ -11,43 +11,42 @@ from exchange import (
 
 class CurrencyExchangeTest(unittest.TestCase):
 
-    @pytest.mark.task(taskno=1)
     def test_exchange_money(self):
         input_data = [(100000, 0.84), (700000, 10.1)]
         output_data = [119047, 69306]
 
         for variant, (input_data, output_data) in enumerate(zip(input_data, output_data), start=1):
             with self.subTest(f"variation #{variant}", input_data=input_data, output_data=output_data):
-                self.assertEqual(int(exchange_money(input_data[0], input_data[1])), output_data)
+                self.assertEqual(
+                    int(exchange_money(input_data[0], input_data[1])), output_data)
 
-    @pytest.mark.task(taskno=2)
     def test_get_change(self):
         input_data = [(463000, 5000), (1250, 120), (15000, 1380)]
         output_data = [458000, 1130, 13620]
 
         for variant, (input_data, output_data) in enumerate(zip(input_data, output_data), start=1):
             with self.subTest(f"variation #{variant}", input_data=input_data, output_data=output_data):
-                self.assertEqual(get_change(input_data[0], input_data[1]), output_data)
+                self.assertEqual(get_change(
+                    input_data[0], input_data[1]), output_data)
 
-    @pytest.mark.task(taskno=3)
     def test_get_value_of_bills(self):
         input_data = [(10000, 128), (50, 360), (200, 200)]
         output_data = [1280000, 18000, 40000]
 
         for variant, (input_data, output_data) in enumerate(zip(input_data, output_data), start=1):
             with self.subTest(f"variation #{variant}", input_data=input_data, output_data=output_data):
-                self.assertEqual(get_value_of_bills(input_data[0], input_data[1]), output_data)
+                self.assertEqual(get_value_of_bills(
+                    input_data[0], input_data[1]), output_data)
 
-    @pytest.mark.task(taskno=4)
     def test_get_number_of_bills(self):
         input_data = [(163270, 50000), (54361, 1000)]
         output_data = [3, 54]
 
         for variant, (input_data, output_data) in enumerate(zip(input_data, output_data), start=1):
             with self.subTest(f"variation #{variant}", input_data=input_data, output_data=output_data):
-                self.assertEqual(get_number_of_bills(input_data[0], input_data[1]), output_data)
+                self.assertEqual(get_number_of_bills(
+                    input_data[0], input_data[1]), output_data)
 
-    @pytest.mark.task(taskno=5)
     def test_exchangeable_value(self):
         inputs = [
             (100000, 10.61, 10, 1),
@@ -60,9 +59,9 @@ class CurrencyExchangeTest(unittest.TestCase):
 
         for variant, (inputs, output_data) in enumerate(zip(inputs, output_data), start=1):
             with self.subTest(f"variation #{variant}", inputs=inputs, output_data=output_data):
-                self.assertEqual(exchangeable_value(inputs[0], inputs[1], inputs[2], inputs[3]), output_data)
+                self.assertEqual(exchangeable_value(
+                    inputs[0], inputs[1], inputs[2], inputs[3]), output_data)
 
-    @pytest.mark.task(taskno=6)
     def test_non_exchangeable_value(self):
         inputs = [
             (100000, 10.61, 10, 1),
@@ -74,4 +73,5 @@ class CurrencyExchangeTest(unittest.TestCase):
 
         for variant, (inputs, output_data) in enumerate(zip(inputs, output_data), start=1):
             with self.subTest(f"variation #{variant}", inputs=inputs, output_data=output_data):
-                self.assertEqual(non_exchangeable_value(inputs[0], inputs[1], inputs[2], inputs[3]), output_data)
+                self.assertEqual(non_exchangeable_value(
+                    inputs[0], inputs[1], inputs[2], inputs[3]), output_data)