Added ability to convert from datetime.date to system_clock::time_point (#1848)

* Added ability to convert from Python datetime.date and datetime.time to C++ system_clock::time_point

tests/test_chrono.py

@@ -40,6 +40,62 @@ def test_chrono_system_clock_roundtrip():
     assert diff.microseconds == 0
 
 
+def test_chrono_system_clock_roundtrip_date():
+    date1 = datetime.date.today()
+
+    # Roundtrip the time
+    datetime2 = m.test_chrono2(date1)
+    date2 = datetime2.date()
+    time2 = datetime2.time()
+
+    # The returned value should be a datetime
+    assert isinstance(datetime2, datetime.datetime)
+    assert isinstance(date2, datetime.date)
+    assert isinstance(time2, datetime.time)
+
+    # They should be identical (no information lost on roundtrip)
+    diff = abs(date1 - date2)
+    assert diff.days == 0
+    assert diff.seconds == 0
+    assert diff.microseconds == 0
+
+    # Year, Month & Day should be the same after the round trip
+    assert date1.year == date2.year
+    assert date1.month == date2.month
+    assert date1.day == date2.day
+
+    # There should be no time information
+    assert time2.hour == 0
+    assert time2.minute == 0
+    assert time2.second == 0
+    assert time2.microsecond == 0
+
+
+def test_chrono_system_clock_roundtrip_time():
+    time1 = datetime.datetime.today().time()
+
+    # Roundtrip the time
+    datetime2 = m.test_chrono2(time1)
+    date2 = datetime2.date()
+    time2 = datetime2.time()
+
+    # The returned value should be a datetime
+    assert isinstance(datetime2, datetime.datetime)
+    assert isinstance(date2, datetime.date)
+    assert isinstance(time2, datetime.time)
+
+    # Hour, Minute, Second & Microsecond should be the same after the round trip
+    assert time1.hour == time2.hour
+    assert time1.minute == time2.minute
+    assert time1.second == time2.second
+    assert time1.microsecond == time2.microsecond
+
+    # There should be no date information (i.e. date = python base date)
+    assert date2.year == 1970
+    assert date2.month == 1
+    assert date2.day == 1
+
+
 def test_chrono_duration_roundtrip():
 
     # Get the difference between two times (a timedelta)
@@ -70,6 +126,19 @@ def test_chrono_duration_subtraction_equivalence():
     assert cpp_diff.microseconds == diff.microseconds
 
 
+def test_chrono_duration_subtraction_equivalence_date():
+
+    date1 = datetime.date.today()
+    date2 = datetime.date.today()
+
+    diff = date2 - date1
+    cpp_diff = m.test_chrono4(date2, date1)
+
+    assert cpp_diff.days == diff.days
+    assert cpp_diff.seconds == diff.seconds
+    assert cpp_diff.microseconds == diff.microseconds
+
+
 def test_chrono_steady_clock():
     time1 = m.test_chrono5()
     assert isinstance(time1, datetime.timedelta)