diff --git a/tests/test_primitive_data/test_bit_string.py b/tests/test_primitive_data/test_bit_string.py
index e69de29..e874ebc 100644
--- a/tests/test_primitive_data/test_bit_string.py
+++ b/tests/test_primitive_data/test_bit_string.py
@@ -0,0 +1,162 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Test Primitive Bit String
+-------------------------
+"""
+
+import unittest
+
+from bacpypes.debugging import bacpypes_debugging, ModuleLogger, xtob
+from bacpypes.primitivedata import BitString, Tag
+
+# some debugging
+_debug = 0
+_log = ModuleLogger(globals())
+
+
+class SampleBitString(BitString):
+    bitLen = 13
+    bitNames = {
+        'b0': 0,
+        'b1': 1,
+        'b4': 4,
+        'b7': 7,
+        'b8': 8,
+        'b12': 12,
+    }
+
+
+@bacpypes_debugging
+def bit_string_tag(x):
+    """Convert a hex string to an bit_string application tag."""
+    if _debug: bit_string_tag._debug("bit_string_tag %r", x)
+
+    b = xtob(x)
+    tag = Tag(Tag.applicationTagClass, Tag.bitStringAppTag, len(b), b)
+    if _debug: bit_string_endec._debug("    - tag: %r", tag)
+
+    return tag
+
+@bacpypes_debugging
+def bit_string_encode(obj):
+    """Encode an BitString object into a tag."""
+    if _debug: bit_string_encode._debug("bit_string_encode %r", obj)
+
+    tag = Tag()
+    obj.encode(tag)
+    if _debug: bit_string_endec._debug("    - tag: %r", tag)
+
+    return tag
+
+
+@bacpypes_debugging
+def bit_string_decode(tag):
+    """Decode an bit_string application tag into an bit_string."""
+    if _debug: bit_string_decode._debug("bit_string_decode %r", tag)
+
+    obj = BitString(tag)
+    if _debug: bit_string_decode._debug("    - obj: %r", obj)
+
+    return obj
+
+
+@bacpypes_debugging
+def bit_string_endec(v, x):
+    """Pass the value to BitString, construct a tag from the hex string,
+    and compare results of encode and decoding each other."""
+    if _debug: bit_string_endec._debug("bit_string_endec %r %r", v, x)
+
+    tag = bit_string_tag(x)
+    if _debug: bit_string_endec._debug("    - tag: %r, %r", tag, tag.tagData)
+
+    obj = BitString(v)
+    if _debug: bit_string_endec._debug("    - obj: %r, %r", obj, obj.value)
+
+    assert bit_string_encode(obj) == tag
+    assert bit_string_decode(tag) == obj
+
+
+@bacpypes_debugging
+class TestBitString(unittest.TestCase):
+
+    def test_bit_string(self):
+        if _debug: TestBitString._debug("test_bit_string")
+
+        obj = BitString()
+        assert obj.value == []
+        assert str(obj) == "BitString()"
+
+        obj = BitString([0])
+        assert obj.value == [0]
+        assert str(obj) == "BitString(0)"
+
+        obj = BitString([0, 1])
+        assert obj.value == [0, 1]
+        assert str(obj) == "BitString(0,1)"
+
+        with self.assertRaises(TypeError):
+            BitString("some string")
+        with self.assertRaises(TypeError):
+            BitString(1.0)
+
+    def test_bit_string_sample(self):
+        if _debug: TestBitString._debug("test_bit_string_sample")
+
+        obj = SampleBitString()
+        assert obj.value == [0] * SampleBitString.bitLen
+
+        obj = SampleBitString([1])
+        assert str(obj) == "BitString(b0)"
+
+        obj = SampleBitString(['b4'])
+        assert str(obj) == "BitString(!b0,!b1,0,0,b4,0,0,!b7,!b8,0,0,0,!b12)"
+
+        with self.assertRaises(TypeError):
+            SampleBitString(["x1"])
+
+    def test_bit_string_tag(self):
+        if _debug: TestBitString._debug("test_bit_string_tag")
+
+        tag = Tag(Tag.applicationTagClass, Tag.bitStringAppTag, 1, xtob('08'))
+        obj = BitString(tag)
+        if _debug: TestBitString._debug("    - obj.value: %r", obj.value)
+        assert obj.value == []
+
+        tag = Tag(Tag.applicationTagClass, Tag.bitStringAppTag, 2, xtob('0102'))
+        obj = BitString(tag)
+        if _debug: TestBitString._debug("    - obj.value: %r", obj.value)
+        assert obj.value == [0, 0, 0, 0, 0, 0, 1]
+
+        tag = Tag(Tag.applicationTagClass, Tag.booleanAppTag, 0, xtob(''))
+        with self.assertRaises(ValueError):
+            BitString(tag)
+
+        tag = Tag(Tag.contextTagClass, 0, 1, xtob('ff'))
+        with self.assertRaises(ValueError):
+            BitString(tag)
+
+        tag = Tag(Tag.openingTagClass, 0)
+        with self.assertRaises(ValueError):
+            BitString(tag)
+
+    def test_bit_string_copy(self):
+        if _debug: TestBitString._debug("test_bit_string_copy")
+
+        sample_value = [0, 1, 0, 1]
+        obj1 = BitString(sample_value)
+        obj2 = BitString(obj1)
+        assert obj2.value == sample_value
+
+    def test_bit_string_endec(self):
+        if _debug: TestBitString._debug("test_bit_string_endec")
+
+        bit_string_endec([], '00')
+        bit_string_endec([0], '0700')
+        bit_string_endec([1], '0780')
+        bit_string_endec([0] * 2, '0600')
+        bit_string_endec([1] * 2, '06c0')
+        bit_string_endec([0] * 10, '060000')
+        bit_string_endec([1] * 10, '06ffc0')
+