Adjustment to UI and Business logic for injecting dependencies

3-tier.py

@@ -19,7 +19,8 @@ def __get__(self, obj, klas):
 class BusinessLogic(object):
     """ Business logic holding data store instances """
 
-    data = Data()
+    def __init__(self, data):
+        self.data = data
 
     def product_list(self):
         return self.data['products'].keys()
@@ -31,8 +32,8 @@ def product_information(self, product):
 class Ui(object):
     """ UI interaction class """
 
-    def __init__(self):
-        self.business_logic = BusinessLogic()
+    def __init__(self, logic):
+        self.business_logic = logic
 
     def get_product_list(self):
         print('PRODUCT LIST:')
@@ -53,7 +54,9 @@ def get_product_information(self, product):
 
 
 def main():
-    ui = Ui()
+    data = Data()
+    logic = BusinessLogic(data)
+    ui = Ui(logic)
     ui.get_product_list()
     ui.get_product_information('cheese')
     ui.get_product_information('eggs')
@@ -69,7 +72,7 @@ def main():
 # cheese
 # eggs
 # milk
-# 
+#
 # (Fetching from Data Store)
 # PRODUCT INFORMATION:
 # Name: Cheese, Price: 2.00, Quantity: 10