Fix time problems on Windows 10

Due to Windows 10[1], Robot Interfaces did produce timestamps that were
before epoch and thus failed when Robot tried to convert them into
results.

Now, if we try to put a timestamp that is before epoch, it is just reset
to epoch.

Also, RF3 interface did not have parity with the RF4 interface -- now it
does

[1] https://stackoverflow.com/a/58203399

src/oxygen/oxygen.py

@@ -99,7 +99,6 @@ def output_file(self, path):
         result.visit(OxygenVisitor(self.run_time_data))
         result.save()
 
-
 class OxygenLibrary(OxygenCore):
     '''Oxygen is a tool to consolidate different test tools' reports together
     as a single Robot Framework log and report. ``oxygen.OxygenLibrary``

src/oxygen/robot3_interface.py

@@ -290,6 +290,11 @@ def ms_to_timestamp(self, milliseconds):
         time_object = datetime.fromtimestamp(int(milliseconds / 1000)) - tz_delta
         milliseconds_delta = timedelta(milliseconds=(milliseconds % 1000))
         time_object = (time_object + milliseconds_delta)
+        if time_object.year < 1970:
+            time_object = datetime.fromtimestamp(0)
+        # fromtimestamp() loses milliseconds, add them back
+        milliseconds_delta = timedelta(milliseconds=(milliseconds % 1000))
+        time_object = (time_object + milliseconds_delta)
 
         time_format = self.get_time_format()
 

src/oxygen/robot4_interface.py

@@ -289,6 +289,9 @@ def ms_to_timestamp(self, milliseconds):
         tz_delta = self.get_timezone_delta()
 
         time_object = datetime.fromtimestamp(int(milliseconds / 1000)) - tz_delta
+        if time_object.year < 1970:
+            time_object = datetime.fromtimestamp(0)
+        # fromtimestamp() loses milliseconds, add them back
         milliseconds_delta = timedelta(milliseconds=(milliseconds % 1000))
         time_object = (time_object + milliseconds_delta)
 

tests/utest/robot_interface/test_time_conversions.py

@@ -29,6 +29,17 @@ def test_should_be_associative(self):
         timestamp = self.interface.result.ms_to_timestamp(milliseconds)
         assert timestamp == '20180807 07:01:24.300000'
 
+    def _validate_timestamp(self, result):
+        timestamp = result.ms_to_timestamp(-10)
+        self.assertEqual(timestamp, '19700101 02:00:00.990000')
+
+    def test_ms_before_epoch_are_reset_to_epoch(self):
+        from oxygen.robot4_interface import RobotResultInterface as RF4ResultIface
+        self._validate_timestamp(RF4ResultIface())
+
+        from oxygen.robot3_interface import RobotResultInterface as RF3ResultIface
+        self._validate_timestamp(RF3ResultIface())
+
 
 class TestTimestampToMs(TestCase):
     def setUp(self):