Add unit tests for the methods in util

tests/test_util.py

@@ -0,0 +1,48 @@
+from lib import util
+
+
+def test_cachedproperty():
+    class Target:
+        def __init__(self):
+            self.call_count = 0
+
+        @util.cachedproperty
+        def prop(self):
+            self.call_count += 1
+            return self.call_count
+
+    t = Target()
+    assert t.prop == t.prop == 1
+
+
+def test_deep_getsizeof():
+    int_t = util.deep_getsizeof(1)
+    assert util.deep_getsizeof([1, 1]) > 2 * int_t
+    assert util.deep_getsizeof({1: 1}) > 2 * int_t
+    assert util.deep_getsizeof({1: {1: 1}}) > 3 * int_t
+
+
+class Base:
+    pass
+
+
+class A(Base):
+    pass
+
+
+class B(Base):
+    pass
+
+
+def test_subclasses():
+    assert util.subclasses(Base) == [A, B]
+
+
+def test_chunks():
+    assert list(util.chunks([1, 2, 3, 4, 5], 2)) == [[1, 2], [3, 4], [5]]
+
+
+def test_increment_byte_string():
+    assert util.increment_byte_string(b'1') == b'2'
+    assert util.increment_byte_string(b'\x01\x01') == b'\x01\x02'
+    assert util.increment_byte_string(b'\xff\xff') == b'\x01\x00\x00'