diff --git a/pyasm/Makefile b/pyasm/Makefile
index 94671b7..0dd3a6c 100644
--- a/pyasm/Makefile
+++ b/pyasm/Makefile
@@ -3,7 +3,8 @@
 #
 
 test:
-	pyasm test.asm
+	cp pyasm pyasm.py
+	python test_pyasm.py
 
 clean:
-	rm -f *.log
+	rm -f *.log pyasm.py
diff --git a/pyasm/test_pyasm.py b/pyasm/test_pyasm.py
new file mode 100644
index 0000000..6c14e52
--- /dev/null
+++ b/pyasm/test_pyasm.py
@@ -0,0 +1,92 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Test the pyasm functions.
+
+Usage: test_pyasm.py [<options>]
+
+where <options> is one or more of
+          -h    prints this help and stops
+"""
+
+import os
+import pyasm
+import unittest
+
+
+class TestPyasm(unittest.TestCase):
+
+    def test_eval_expression(self):
+        """Run tests on eval(expression).
+
+        eval_expression(expr, dot) with SymTable global
+        """
+
+        # define tests: (test, dot, symtable, expected, undefined, raises)
+        tests = (
+                 ('a', 0100, {'A': 1}, 1, None, False),
+                 ('.', 0100, {}, 0100, None, False),
+                 ('b', 0100, {}, None, 'B', True),
+                 ('a+1', 0100, {'A': 1}, 2, None, False),
+                 ('a+b', 0, {'A': 1, 'B': 2}, 3, None, False),
+                 ('a + b', 0, {'A': 1, 'B': 2}, 3, None, False),
+                 ('a / b', 0, {'A': 4, 'B': 2}, 2, None, False),
+                 ('. + 0100', 0100, {}, 0200, None, False),
+                )
+
+        # now run them
+        for (test, dot, symtable, expected, undefined, raises) in tests:
+            pyasm.Undefined = None
+            pyasm.SymTable = symtable
+            if raises:
+                result = None
+                with self.assertRaises(NameError):
+                    result = pyasm.eval_expression(test, dot)
+            else:
+                result = pyasm.eval_expression(test, dot)
+            msg = ("Expected eval_expression('%s', '%s') to return '%s', got '%s'"
+                   % (test, str(dot), str(expected), str(result)))
+            self.assertEqual(result, expected, msg)
+            msg = ("Expected eval_expression('%s', '%s') to set Undefined to '%s', got '%s'"
+                   % (test, str(dot), str(undefined), str(pyasm.Undefined)))
+            self.assertEqual(undefined, pyasm.Undefined, msg)
+
+    def test_split_fields(self):
+        """Run lots of tests on split_fields()."""
+
+        # define tests: (test, expected)
+        tests = (('label opcode value ;comment', ('LABEL', 'OPCODE', 'value')),
+                 ('',                            (None, None, None)),
+                 (';comment',                    (None, None, None)),
+                 ('; comment',                   (None, None, None)),
+                 (' ; comment',                  (None, None, None)),
+                 ('\t; comment',                 (None, None, None)),
+                 ('label',                       ('LABEL', None, None)),
+                 (' opcode',                     (None, 'OPCODE', None)),
+                 ('\topcode',                    (None, 'OPCODE', None)),
+                 ('label opcode',                ('LABEL', 'OPCODE', None)),
+                 ('label\topcode',               ('LABEL', 'OPCODE', None)),
+                 ('label opcode value',          ('LABEL', 'OPCODE', 'value')),
+                 ('label\topcode value',         ('LABEL', 'OPCODE', 'value')),
+                 ('label\topcode\tvalue',        ('LABEL', 'OPCODE', 'value')),
+                 ('label opcode a+b',            ('LABEL', 'OPCODE', 'a+b')),
+                 ('label opcode a + b',          ('LABEL', 'OPCODE', 'a + b')),
+                 ('      opcode a + b',          (None, 'OPCODE', 'a + b')),
+                 ('      opcode a + b ;comment', (None, 'OPCODE', 'a + b')),
+                 ('      opcode',                (None, 'OPCODE', None)),
+                )
+
+        # now run them
+        for (test, expected) in tests:
+            result = pyasm.split_fields(test)
+            msg = ("Expected split_fields('%s') to return '%s', got '%s'"
+                   % (test, str(expected), str(result)))
+            self.assertEqual(result, expected, msg)
+
+################################################################################
+
+if __name__ == '__main__':
+    suite = unittest.makeSuite(TestPyasm, 'test')
+    runner = unittest.TextTestRunner()
+    runner.run(suite)