12 files changed, 36 insertions, 43 deletions

diff --git a/glucometer.py b/glucometer.py
index 9ec781c..abed647 100755
--- a/glucometer.py
+++ b/glucometer.py
@@ -48,7 +48,8 @@ def main():
   parser_dump = subparsers.add_parser(
     'dump', help='Dump the readings stored in the device.')
   parser_dump.add_argument(
-    '--unit', action='store', choices=common.VALID_UNITS,
+    '--unit', action='store',
+    choices=[unit.value for unit in common.Unit],
     help='Select the unit to use for the dumped data.')
   parser_dump.add_argument(
     '--sort-by', action='store', default='timestamp',
diff --git a/glucometerutils/common.py b/glucometerutils/common.py
index 3f61932..9350983 100644
--- a/glucometerutils/common.py
+++ b/glucometerutils/common.py
@@ -7,15 +7,14 @@ __copyright__ = 'Copyright © 2013, Diego Elio Pettenò'
 __license__ = 'MIT'
 
 import collections
+import enum
 import textwrap
 
 from glucometerutils import exceptions
 
-# Constants for units
-UNIT_MGDL = 'mg/dL'
-UNIT_MMOLL = 'mmol/L'
-
-VALID_UNITS = [UNIT_MGDL, UNIT_MMOLL]
+class Unit(enum.Enum):
+  MG_DL = 'mg/dL'
+  MMOL_L = 'mmol/L'
 
 # Constants for meal information
 NO_MEAL = ''
@@ -41,17 +40,10 @@ def convert_glucose_unit(value, from_unit, to_unit=None):
   Raises:
     exceptions.InvalidGlucoseUnit: If the parameters are incorrect.
   """
-  if from_unit not in VALID_UNITS:
-    raise exceptions.InvalidGlucoseUnit(from_unit)
-
   if from_unit == to_unit:
     return value
 
-  if to_unit is not None:
-    if to_unit not in VALID_UNITS:
-      raise exceptions.InvalidGlucoseUnit(to_unit)
-
-  if from_unit is UNIT_MGDL:
+  if from_unit is Unit.MG_DL:
     return round(value / 18.0, 2)
   else:
     return round(value * 18.0, 0)
@@ -86,9 +78,9 @@ class GlucoseReading(_ReadingBase):
     """Returns the reading value as the given unit.
 
     Args:
-      to_unit: (UNIT_MGDL|UNIT_MMOLL) The unit to return the value to.
+      to_unit: (Unit) The unit to return the value to.
     """
-    return convert_glucose_unit(self.value, UNIT_MGDL, to_unit)
+    return convert_glucose_unit(self.value, Unit.MG_DL, to_unit)
 
   def as_csv(self, unit):
     """Returns the reading as a formatted comma-separated value string."""
@@ -129,14 +121,14 @@ _MeterInfoBase = collections.namedtuple(
 
 class MeterInfo(_MeterInfoBase):
   def __new__(cls, model, serial_number='N/A', version_info=(),
-              native_unit=UNIT_MGDL):
+              native_unit=Unit.MG_DL):
     """Construct a meter information object.
 
     Args:
       model: (string) Human-readable model name, depending on driver.
       serial_number: (string) Optional serial number to identify the device.
       version_info: (list(string)) Optional hardware/software version information.
-      native_unit: (UNIT_MGDL|UNIT_MMOLL) Native unit of the device for display.
+      native_unit: (Unit) Native unit of the device for display.
     """
     return super(MeterInfo, cls).__new__(
       cls, model=model, serial_number=serial_number, version_info=version_info,
diff --git a/glucometerutils/drivers/accuchek_reports.py b/glucometerutils/drivers/accuchek_reports.py
index 2ae41ba..03eeddd 100644
--- a/glucometerutils/drivers/accuchek_reports.py
+++ b/glucometerutils/drivers/accuchek_reports.py
@@ -26,8 +26,8 @@ from glucometerutils import common
 from glucometerutils import exceptions
 
 _UNIT_MAP = {
-  'mmol/l': common.UNIT_MMOLL,
-  'mg/dl': common.UNIT_MGDL,
+  'mmol/l': common.Unit.MMOL_L,
+  'mg/dl': common.Unit.MG_DL,
 }
 
 _DATE_CSV_KEY = 'Date'
diff --git a/glucometerutils/drivers/fsinsulinx.py b/glucometerutils/drivers/fsinsulinx.py
index 90abc7e..15bc131 100644
--- a/glucometerutils/drivers/fsinsulinx.py
+++ b/glucometerutils/drivers/fsinsulinx.py
@@ -57,7 +57,7 @@ class Device(freestyle.FreeStyleHidDevice):
 
     def get_glucose_unit(self):
         """Returns the glucose unit of the device."""
-        return common.UNIT_MGDL
+        return common.Unit.MG_DL
 
     def get_readings(self):
         """Iterate through the reading records in the device."""
diff --git a/glucometerutils/drivers/fslibre.py b/glucometerutils/drivers/fslibre.py
index a0f0517..52632b3 100644
--- a/glucometerutils/drivers/fslibre.py
+++ b/glucometerutils/drivers/fslibre.py
@@ -209,7 +209,7 @@ class Device(freestyle.FreeStyleHidDevice):
         """Returns the glucose unit of the device."""
         # TODO(Flameeyes): figure out how to identify the actual unit on the
         # device.
-        return common.UNIT_MGDL
+        return common.Unit.MG_DL
 
     def get_readings(self):
 
diff --git a/glucometerutils/drivers/fsoptium.py b/glucometerutils/drivers/fsoptium.py
index 121d8d6..5c57ae3 100644
--- a/glucometerutils/drivers/fsoptium.py
+++ b/glucometerutils/drivers/fsoptium.py
@@ -119,9 +119,9 @@ class Device(serial.SerialDevice):
       elif parsed_line[0] == 'Ver:':
         self.device_version_ = parsed_line[1]
         if parsed_line[2] == 'MMOL':
-          self.device_glucose_unit_ = common.UNIT_MMOLL
+          self.device_glucose_unit_ = common.Unit.MMOL_L
         else:  # I only have a mmol/l device, so I can't be sure.
-          self.device_glucose_unit_ = common.UNIT_MGDL
+          self.device_glucose_unit_ = common.Unit.MG_DL
       # There are more entries: Clock, Market, ROM and Usage, but we don't care
       # for those here.
       elif parsed_line[0] == 'CMD OK':
@@ -164,8 +164,8 @@ class Device(serial.SerialDevice):
     """Returns a constant representing the unit displayed by the meter.
 
     Returns:
-      common.UNIT_MGDL: if the glucometer displays in mg/dL
-      common.UNIT_MMOLL: if the glucometer displays in mmol/L
+      common.Unit.MG_DL: if the glucometer displays in mg/dL
+      common.Unit.MMOL_L: if the glucometer displays in mmol/L
     """
     return self.device_glucose_unit_
 
diff --git a/glucometerutils/drivers/fsprecisionneo.py b/glucometerutils/drivers/fsprecisionneo.py
index 6fd07c2..cb58263 100644
--- a/glucometerutils/drivers/fsprecisionneo.py
+++ b/glucometerutils/drivers/fsprecisionneo.py
@@ -66,7 +66,7 @@ class Device(freestyle.FreeStyleHidDevice):
 
     def get_glucose_unit(self):
         """Returns the glucose unit of the device."""
-        return common.UNIT_MGDL
+        return common.Unit.MG_DL
 
     def get_readings(self):
         """Iterate through the reading records in the device."""
diff --git a/glucometerutils/drivers/otultra2.py b/glucometerutils/drivers/otultra2.py
index e9f60bb..f44bc15 100644
--- a/glucometerutils/drivers/otultra2.py
+++ b/glucometerutils/drivers/otultra2.py
@@ -262,8 +262,8 @@ class Device(serial.SerialDevice):
     """Returns a constant representing the unit displayed by the meter.
 
     Returns:
-      common.UNIT_MGDL: if the glucometer displays in mg/dL
-      common.UNIT_MMOLL: if the glucometer displays in mmol/L
+      common.Unit.MG_DL: if the glucometer displays in mg/dL
+      common.Unit.MMOL_L: if the glucometer displays in mmol/L
 
     Raises:
       exceptions.InvalidGlucoseUnit: if the unit is not recognized
@@ -279,9 +279,9 @@ class Device(serial.SerialDevice):
     unit = match.group(1)
 
     if unit == 'MG/DL ':
-      return common.UNIT_MGDL
+      return common.Unit.MG_DL
     elif unit == 'MMOL/L':
-      return common.UNIT_MMOLL
+      return common.Unit.MMOL_L
     else:
       raise exceptions.InvalidGlucoseUnit(string)
 
diff --git a/glucometerutils/drivers/otultraeasy.py b/glucometerutils/drivers/otultraeasy.py
index 461de26..0538dac 100644
--- a/glucometerutils/drivers/otultraeasy.py
+++ b/glucometerutils/drivers/otultraeasy.py
@@ -295,9 +295,9 @@ class Device(serial.SerialDevice):
     response = self._read_response()
 
     if response.data[2] == 0:
-      return common.UNIT_MGDL
+      return common.Unit.MG_DL
     elif response.data[2] == 1:
-      return common.UNIT_MMOLL
+      return common.Unit.MMOL_L
     else:
       raise lifescan.MalformedCommand(
         'at position PM1 invalid value %02x for unit' % response.data[2])
diff --git a/glucometerutils/drivers/otverio2015.py b/glucometerutils/drivers/otverio2015.py
index 9dc9393..c416678 100644
--- a/glucometerutils/drivers/otverio2015.py
+++ b/glucometerutils/drivers/otverio2015.py
@@ -243,9 +243,9 @@ class Device(object):
   def get_glucose_unit(self):
     unit_value = self._read_parameter(_PARAMETER_KEY_UNIT)
     if unit_value == b'\x00\x00\x00\x00':
-      return common.UNIT_MGDL
+      return common.Unit.MG_DL
     elif unit_value == b'\x01\x00\x00\x00':
-      return common.UNIT_MMOLL
+      return common.Unit.MMOL_L
     else:
       raise exceptions.InvalidGlucoseUnit('%r' % unit_value)
 
diff --git a/glucometerutils/drivers/sdcodefree.py b/glucometerutils/drivers/sdcodefree.py
index 8b07ab5..4939361 100644
--- a/glucometerutils/drivers/sdcodefree.py
+++ b/glucometerutils/drivers/sdcodefree.py
@@ -164,7 +164,7 @@ class Device(serial.SerialDevice):
 
     def get_glucose_unit(self):
         # Device does not provide information on glucose unit.
-        return common.UNIT_MGDL
+        return common.Unit.MG_DL
 
     def get_datetime(self):
         raise NotImplementedError
diff --git a/test/test_common.py b/test/test_common.py
index 07b65d9..febf578 100644
--- a/test/test_common.py
+++ b/test/test_common.py
@@ -19,31 +19,31 @@ class TestCommon(unittest.TestCase):
     def test_glucose_conversion(self):
         self.assertEqual(
             5.56, common.convert_glucose_unit(
-                100, common.UNIT_MGDL, common.UNIT_MMOLL))
+                100, common.Unit.MG_DL, common.Unit.MMOL_L))
 
         self.assertEqual(
             5.56, common.convert_glucose_unit(
-                100, common.UNIT_MGDL))
+                100, common.Unit.MG_DL))
 
         self.assertEqual(
             180, common.convert_glucose_unit(
-                10, common.UNIT_MMOLL, common.UNIT_MGDL))
+                10, common.Unit.MMOL_L, common.Unit.MG_DL))
 
         self.assertEqual(
             180, common.convert_glucose_unit(
-                10, common.UNIT_MMOLL))
+                10, common.Unit.MMOL_L))
 
         self.assertEqual(
             100, common.convert_glucose_unit(
-                100, common.UNIT_MGDL, common.UNIT_MGDL))
+                100, common.Unit.MG_DL, common.Unit.MG_DL))
 
         self.assertEqual(
             10, common.convert_glucose_unit(
-                10, common.UNIT_MMOLL, common.UNIT_MMOLL))
+                10, common.Unit.MMOL_L, common.Unit.MMOL_L))
 
         self.assertRaises(
             exceptions.InvalidGlucoseUnit,
-            common.convert_glucose_unit, common.UNIT_MMOLL, 'foo')
+            common.convert_glucose_unit, common.Unit.MMOL_L, 'foo')
 
 if __name__ == '__main__':
         unittest.main()