Add new tests (aimacode#314)

- Added tests for PluralityLearner, NaiveBayes and kNN algorithms

- Replace parse_csv with non-trivial input

Author: antmarakis

tests/test_learning.py

@@ -1,9 +1,12 @@
 import pytest
-from learning import parse_csv, weighted_mode, weighted_replicate
+from learning import parse_csv, weighted_mode, weighted_replicate, DataSet, \
+                     PluralityLearner, NaiveBayesLearner, NearestNeighborLearner
+from utils import DataFile
 
 
 def test_parse_csv():
-    assert parse_csv('1, 2, 3 \n 0, 2, na') == [[1, 2, 3], [0, 2, 'na']]
+    Iris = DataFile('iris.csv').read()
+    assert parse_csv(Iris)[0] == [5.1,3.5,1.4,0.2,'setosa']
 
 
 def test_weighted_mode():
@@ -12,3 +15,21 @@ def test_weighted_mode():
 
 def test_weighted_replicate():
     assert weighted_replicate('ABC', [1, 2, 1], 4) == ['A', 'B', 'B', 'C']
+
+def test_plurality_learner():
+    zoo = DataSet(name="zoo")
+
+    pL = PluralityLearner(zoo)
+    assert pL([]) == "mammal"
+
+def test_naive_bayes():
+    iris = DataSet(name="iris")
+
+    nB = NaiveBayesLearner(iris)
+    assert nB([5,3,1,0.1]) == "setosa"
+
+def test_k_nearest_neighbors():
+    iris = DataSet(name="iris")
+
+    kNN = NearestNeighborLearner(iris,k=3)
+    assert kNN([5,3,1,0.1]) == "setosa"