Merge pull request matplotlib#25815 from ksunden/jpl_unit_date_ob1

[TST] Make jpl units instantiated with datetimes consistent with mpl converters

Author: QuLogic

lib/matplotlib/testing/jpl_units/EpochConverter.py

@@ -12,9 +12,7 @@ class EpochConverter(units.ConversionInterface):
     classes.
     """
 
-    # julian date reference for "Jan 1, 0001" minus 1 day because
-    # Matplotlib really wants "Jan 0, 0001"
-    jdRef = 1721425.5 - 1
+    jdRef = 1721425.5
 
     @staticmethod
     def axisinfo(unit, axis):

lib/matplotlib/tests/test_axes.py

@@ -922,8 +922,8 @@ def test_axvspan_epoch():
     units.register()
 
     # generate some data
-    t0 = units.Epoch("ET", dt=datetime.datetime(2009, 1, 20))
-    tf = units.Epoch("ET", dt=datetime.datetime(2009, 1, 21))
+    t0 = units.Epoch("ET", dt=datetime.datetime(2009, 1, 21))
+    tf = units.Epoch("ET", dt=datetime.datetime(2009, 1, 22))
     dt = units.Duration("ET", units.day.convert("sec"))
 
     ax = plt.gca()
@@ -937,8 +937,8 @@ def test_axhspan_epoch():
     units.register()
 
     # generate some data
-    t0 = units.Epoch("ET", dt=datetime.datetime(2009, 1, 20))
-    tf = units.Epoch("ET", dt=datetime.datetime(2009, 1, 21))
+    t0 = units.Epoch("ET", dt=datetime.datetime(2009, 1, 21))
+    tf = units.Epoch("ET", dt=datetime.datetime(2009, 1, 22))
     dt = units.Duration("ET", units.day.convert("sec"))
 
     ax = plt.gca()

lib/matplotlib/tests/test_units.py

@@ -134,7 +134,7 @@ def test_jpl_bar_units():
     day = units.Duration("ET", 24.0 * 60.0 * 60.0)
     x = [0 * units.km, 1 * units.km, 2 * units.km]
     w = [1 * day, 2 * day, 3 * day]
-    b = units.Epoch("ET", dt=datetime(2009, 4, 25))
+    b = units.Epoch("ET", dt=datetime(2009, 4, 26))
     fig, ax = plt.subplots()
     ax.bar(x, w, bottom=b)
     ax.set_ylim([b - 1 * day, b + w[-1] + (1.001) * day])
@@ -149,13 +149,24 @@ def test_jpl_barh_units():
     day = units.Duration("ET", 24.0 * 60.0 * 60.0)
     x = [0 * units.km, 1 * units.km, 2 * units.km]
     w = [1 * day, 2 * day, 3 * day]
-    b = units.Epoch("ET", dt=datetime(2009, 4, 25))
+    b = units.Epoch("ET", dt=datetime(2009, 4, 26))
 
     fig, ax = plt.subplots()
     ax.barh(x, w, left=b)
     ax.set_xlim([b - 1 * day, b + w[-1] + (1.001) * day])
 
 
+def test_jpl_datetime_units_consistent():
+    import matplotlib.testing.jpl_units as units
+    units.register()
+
+    dt = datetime(2009, 4, 26)
+    jpl = units.Epoch("ET", dt=dt)
+    dt_conv = munits.registry.get_converter(dt).convert(dt, None, None)
+    jpl_conv = munits.registry.get_converter(jpl).convert(jpl, None, None)
+    assert dt_conv == jpl_conv
+
+
 def test_empty_arrays():
     # Check that plotting an empty array with a dtype works
     plt.scatter(np.array([], dtype='datetime64[ns]'), np.array([]))