diff --git a/tests/test_modbus.py b/tests/test_modbus.py
index 117e762..eccdeea 100644
--- a/tests/test_modbus.py
+++ b/tests/test_modbus.py
@@ -1,36 +1,32 @@
-import unittest
 from pyhoff.modbus import _get_bits, _get_words, _from_bits, _from_words
 
 
-class TestModbusFunctions(unittest.TestCase):
-
-    def test_get_bits(self):
-        data = bytes([0b11101010, 0b11010101])
-        bit_number = 16
-        expected = [False, True, False, True, False, True, True, True,
-                    True, False, True, False, True, False, True, True]
-        result = _get_bits(data, bit_number)
-        self.assertEqual(result, expected)
-
-    def test_get_words(self):
-        data = bytes([0x12, 0x34, 0x56, 0x78])
-        expected = [0x1234, 0x5678]
-        result = _get_words(data)
-        self.assertEqual(result, expected)
-
-    def test_from_bits(self):
-        values = [False, True, False, True, False, True, True, True,
-                  True, False, True, False, True, False, True, True]
-        expected = bytes([0b11101010, 0b11010101])
-        result = _from_bits(values)
-        self.assertEqual(result, expected)
-
-    def test_from_words(self):
-        values = [0x1234, 0x5678]
-        expected = bytes([0x12, 0x34, 0x56, 0x78])
-        result = _from_words(values)
-        self.assertEqual(result, expected)
+def test_get_bits():
+    data = bytes([0b11101010, 0b11010101])
+    bit_number = 16
+    expected = [False, True, False, True, False, True, True, True,
+                True, False, True, False, True, False, True, True]
+    result = _get_bits(data, bit_number)
+    assert result == expected
 
 
-if __name__ == '__main__':
-    unittest.main()
+def test_get_words():
+    data = bytes([0x12, 0x34, 0x56, 0x78])
+    expected = [0x1234, 0x5678]
+    result = _get_words(data)
+    assert result == expected
+
+
+def test_from_bits():
+    values = [False, True, False, True, False, True, True, True,
+              True, False, True, False, True, False, True, True]
+    expected = bytes([0b11101010, 0b11010101])
+    result = _from_bits(values)
+    assert result == expected
+
+
+def test_from_words():
+    values = [0x1234, 0x5678]
+    expected = bytes([0x12, 0x34, 0x56, 0x78])
+    result = _from_words(values)
+    assert result == expected