Updated TS tests for median, mean, stddev, and accuracy

lib/ts.py

@@ -16,6 +16,10 @@ def __init__(self, data = None, accuracy=None):
     def __len__(self):
         return len(self.data)
 
+    def __getitem__(self, idx):
+        return self.data[idx]
+
+
     def append(self , d):
         if self.accuracy:
             d = round(d, self.accuracy)
@@ -35,7 +39,10 @@ def __str__(self):
     def mean(self):
         if len(self) == 0:
             raise ValueError('Arithmetic mean of empty time series.')
-        return sum(self.data) / float(len(self))
+        m = sum(self.data) / float(len(self))
+        if self.accuracy:
+            return round(m, self.accuracy)
+        return m
 
     def median(self):
         if len(self) == 0:
@@ -49,4 +56,7 @@ def stddev(self):
             raise ValueError('Standard deviation of too few values')
         m = self.mean()
         ss = sum((x-m)**2 for x in self.data)
-        return (ss/float(ld))**0.5
+        std = (ss/float(ld))**0.5
+        if self.accuracy:
+            return round(std, self.accuracy)
+        return std

tests/test_ts.py

@@ -17,3 +17,31 @@ def test_ts(self):
         ts.append( 5.0 )
         self.assertEqual( len(ts) , 3 )
         self.assertEqual( ts.mean() , 2.0 )
+
+    def setUp(self):
+        self._ts  = TS( [2.71828,3.141592,4.12310] )
+        self._tsa = TS( [2.71828,3.141592,4.12310], accuracy=2 )
+        self._tsb = TS( [6.1, 5.2, 4.3, 1.2, 2.3, 4.5, 5.6, 1000.123] )
+        self._tsc = TS( [6.1, 5.2, 4.3, 1.2, 2.3, 4.5, 5.6, 10.0,12.3] )
+
+    def test_ts_init(self):
+        self.assertEqual(3, len(self._ts))
+        self.assertEqual(3, len(self._tsa))
+        self.assertEqual(8, len(self._tsb))
+        self.assertEqual(9, len(self._tsc))
+        self.assertEqual(2.72, self._tsa[0])
+
+    def test_math_with_accuracy(self):
+        self.assertEqual(3.141592, self._ts.median())
+        self.assertEqual(3.14, self._tsa.median())
+
+        self.assertAlmostEqual(3.3276573, self._ts.mean())
+        self.assertEqual(3.33, self._tsa.mean())
+
+        self.assertAlmostEqual(0.5884131, self._ts.stddev())
+        self.assertEqual(0.59, self._tsa.stddev())
+
+    def test_median(self):
+        self.assertEqual(3.141592, self._ts.median())
+        self.assertEqual(5.2, self._tsb.median())
+        self.assertEqual(5.2, self._tsc.median())