diff --git a/NanoVNASaver/Touchstone.py b/NanoVNASaver/Touchstone.py
index f917170..7115822 100644
--- a/NanoVNASaver/Touchstone.py
+++ b/NanoVNASaver/Touchstone.py
@@ -64,12 +64,12 @@ class Options:
     def parse(self, line: str):
         if not line.startswith("#"):
             raise TypeError("Not an option line: " + line)
-        pfact = pparam = pformat = presist = False
+        punit = pparam = pformat = presist = False
         params = iter(line[1:].lower().split())
         for p in params:
-            if p in Options.VALID_UNITS and not pfact:
-                self.factor = Options.UNIT_TO_FACTOR[p]
-                pfact = True
+            if p in Options.VALID_UNITS and not punit:
+                self.unit = p
+                punit = True
             elif p in Options.VALID_PARAMETERS and not pparam:
                 self.parameter = p
                 pparam = True
diff --git a/test/test_touchstone.py b/test/test_touchstone.py
new file mode 100644
index 0000000..3ae0747
--- /dev/null
+++ b/test/test_touchstone.py
@@ -0,0 +1,74 @@
+#  NanoVNASaver
+#  A python program to view and export Touchstone data from a NanoVNA
+#  Copyright (C) 2019.  Rune B. Broberg
+#
+#  This program is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation, either version 3 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import sys
+import unittest
+
+# Import targets to be tested
+from NanoVNASaver.Touchstone import Options, Touchstone
+
+class TestTouchstoneOptions(unittest.TestCase):
+    def setUp(self):
+        self.opts = Options()
+
+    def test_defaults(self):
+        self.assertEqual(self.opts.unit, "ghz")
+        self.assertEqual(self.opts.parameter, "s")
+        self.assertEqual(self.opts.format, "ma")
+        self.assertEqual(self.opts.resistance, 50)
+        self.assertEqual(self.opts.factor, 1000000000)
+        self.assertEqual(str(self.opts), "# GHZ S MA R 50")
+
+    def test_parse(self):
+        self.assertRaisesRegex(
+            TypeError, "Not an option line:",
+            self.opts.parse, "")
+        self.assertRaisesRegex(
+            TypeError, "Not an option line: !",
+            self.opts.parse, "!")
+        self.assertRaisesRegex(
+            TypeError, "Illegal option line: # ILLEGAL",
+            self.opts.parse, "# ILLEGAL")
+        self.assertRaisesRegex(
+            TypeError, "Illegal option line: # GHz mhz",
+            self.opts.parse, "# GHz mhz")
+        self.opts.parse('# khz')
+        self.assertEqual(str(self.opts), "# KHZ S MA R 50")
+        self.assertEqual(self.opts.factor, 1000)
+        self.opts.parse('# r 123 ri hz y')
+        self.assertEqual(str(self.opts), "# HZ Y RI R 123")
+        self.assertEqual(self.opts.factor, 1)
+
+class TestTouchstoneTouchstone(unittest.TestCase):
+
+    def test_load(self):
+        ts = Touchstone("./test/data/valid.s1p")
+        ts.load()
+        self.assertEqual(str(ts.opts), "# HZ S RI R 50")
+        self.assertEqual(len(ts.s11data), 1010)
+        self.assertEqual(len(ts.s21data), 0)
+
+        ts = Touchstone("./test/data/valid.s2p")
+        ts.load()
+        self.assertEqual(str(ts.opts), "# HZ S RI R 50")
+        self.assertEqual(len(ts.s11data), 1020)
+        self.assertEqual(len(ts.s21data), 1020)
+        self.assertEqual(len(ts.s12data), 1020)
+        self.assertEqual(len(ts.s22data), 1020)
+        self.assertIn("! Vector Network Analyzer VNA R2", ts.comments)
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)