Feature/additional tests (#578)

* add test for FunctionFormatter

* add more predicates tests

* add tests for is_non_string_iterable

* rm unnecessary imoprt

* add is_non_string_iterable test for sequence

tests/test_formats.py

@@ -106,3 +106,11 @@ def test_distribution_formatter():
     30.00%
     38.33%
     """)
+
+
+def test_function_formatter():
+    def _mult_ten(v):
+        return v * 10
+
+    func_formatter = formats.FunctionFormatter(_mult_ten)
+    assert func_formatter.format_value(5) == '50'

tests/test_predicates.py

@@ -9,6 +9,16 @@ def test_both():
     ps = [p(x) for x in range(1, 6)]
     assert ps == [False, False, True, False, False]
 
+def test_tautology():
+    p = are.above(3) | are.below(4)
+    ps = [p(x) for x in range(1, 6)]
+    assert ps == [True, True, True, True, True]
+
+def test_contradiction():
+    p = are.above(3) & are.below(3)
+    ps = [p(x) for x in range(1, 6)]
+    assert ps == [False, False, False, False, False]
+
 def test_either():
     """Either f or g."""
     p = are.above(3) | are.below(2)

tests/test_util.py

@@ -4,6 +4,7 @@
 from datascience import util
 import numpy as np
 import pytest
+from collections.abc import Sequence
 
 def test_doctests():
     results = doctest.testmod(util, optionflags=doctest.NORMALIZE_WHITESPACE)
@@ -96,3 +97,26 @@ def test_proportions_from_distribution():
     uniform = u.column(1)
     assert len(uniform) == 50 and _round_eq(1, sum(uniform))
     assert [x in (0, 0.5, 1) for x in ds.sample_proportions(2, ds.make_array(.2, .3, .5))]
+
+
+def test_is_non_string_iterable():
+    is_string = 'hello'
+    assert ds.is_non_string_iterable(is_string) == False
+
+    is_list = [1, 2, 3]
+    assert ds.is_non_string_iterable(is_list) == True
+
+    is_int = 1
+    assert ds.is_non_string_iterable(is_int) == False
+
+    class IsSequence(Sequence):
+        """
+        Implementation of Sequence abc without __iter__
+        """
+        def __getitem__(self, index):
+            pass
+
+        def __len__(self):
+            pass
+    is_sequence = IsSequence()
+    assert ds.is_non_string_iterable(is_sequence) == True