Refactored to use price_history - trend test still failing

Siddharta Govindaraj · Siddharta Govindaraj · commit 029445c361ea · 2015-03-23T10:28:53.000+05:30
diff --git a/stock_alerter/stock.py b/stock_alerter/stock.py
@@ -1,9 +1,14 @@
 class Stock:
     def __init__(self, symbol):
         self.symbol = symbol
-        self.price = None
+        self.price_history = []
+
+    @property
+    def price(self):
+        return self.price_history[-1] \
+            if self.price_history else None
 
     def update(self, timestamp, price):
         if price < 0:
             raise ValueError("price should not be negative")
-        self.price = price
+        self.price_history.append(price)
diff --git a/stock_alerter/tests/test_stock.py b/stock_alerter/tests/test_stock.py
@@ -27,3 +27,11 @@ def test_stock_price_should_give_the_latest_price(self):
         self.goog.update(datetime(2014, 2, 12), price=10)
         self.goog.update(datetime(2014, 2, 13), price=8.4)
         self.assertAlmostEqual(8.4, self.goog.price, delta=0.0001)
+
+    def test_increasing_trend_is_true_if_price_increase_for_3_updates(self):
+        timestamps = [datetime(2014, 2, 11), datetime(2014, 2, 12),
+                      datetime(2014, 2, 13)]
+        prices = [8, 10, 12]
+        for timestamp, price in zip(timestamps, prices):
+            self.goog.update(timestamp, price)
+        self.assertTrue(self.goog.is_increasing_trend())
