3 files changed, 11 insertions, 17 deletions

diff --git a/glucometerutils/common.py b/glucometerutils/common.py
index 31584b4..318fc86 100644
--- a/glucometerutils/common.py
+++ b/glucometerutils/common.py
@@ -28,7 +28,7 @@ class MeasurementMethod(enum.Enum):
   CGM = 'CGM' # Continuous Glucose Monitoring
 
 
-def convert_glucose_unit(value, from_unit, to_unit=None):
+def convert_glucose_unit(value, from_unit, to_unit):
   """Convert the given value of glucose level between units.
 
   Args:
@@ -38,14 +38,14 @@ def convert_glucose_unit(value, from_unit, to_unit=None):
 
   Returns:
     The converted representation of the blood glucose level.
-
-  Raises:
-    exceptions.InvalidGlucoseUnit: If the parameters are incorrect.
   """
+  from_unit = Unit(from_unit)
+  to_unit = Unit(to_unit)
+
   if from_unit == to_unit:
     return value
 
-  if from_unit is Unit.MG_DL:
+  if from_unit == Unit.MG_DL:
     return round(value / 18.0, 2)
   else:
     return round(value * 18.0, 0)
diff --git a/glucometerutils/drivers/accuchek_reports.py b/glucometerutils/drivers/accuchek_reports.py
index d55ac0f..404ed9b 100644
--- a/glucometerutils/drivers/accuchek_reports.py
+++ b/glucometerutils/drivers/accuchek_reports.py
@@ -130,6 +130,8 @@ class Device(object):
 
       yield common.GlucoseReading(
         self._extract_datetime(record),
-        common.convert_glucose_unit(float(record[_RESULT_CSV_KEY]),
-                                    _UNIT_MAP[record[_UNIT_CSV_KEY]]),
+        common.convert_glucose_unit(
+          float(record[_RESULT_CSV_KEY]),
+          _UNIT_MAP[record[_UNIT_CSV_KEY]],
+          common.Unit.MG_DL),
         meal=self._extract_meal(record))
diff --git a/test/test_common.py b/test/test_common.py
index febf578..8ca50e1 100644
--- a/test/test_common.py
+++ b/test/test_common.py
@@ -22,18 +22,10 @@ class TestCommon(unittest.TestCase):
                 100, common.Unit.MG_DL, common.Unit.MMOL_L))
 
         self.assertEqual(
-            5.56, common.convert_glucose_unit(
-                100, common.Unit.MG_DL))
-
-        self.assertEqual(
             180, common.convert_glucose_unit(
                 10, common.Unit.MMOL_L, common.Unit.MG_DL))
 
         self.assertEqual(
-            180, common.convert_glucose_unit(
-                10, common.Unit.MMOL_L))
-
-        self.assertEqual(
             100, common.convert_glucose_unit(
                 100, common.Unit.MG_DL, common.Unit.MG_DL))
 
@@ -42,8 +34,8 @@ class TestCommon(unittest.TestCase):
                 10, common.Unit.MMOL_L, common.Unit.MMOL_L))
 
         self.assertRaises(
-            exceptions.InvalidGlucoseUnit,
-            common.convert_glucose_unit, common.Unit.MMOL_L, 'foo')
+            ValueError,
+            common.convert_glucose_unit, 10, common.Unit.MMOL_L, 'foo')
 
 if __name__ == '__main__':
         unittest.main()