Add test for pandas timeseries as valid x in StationPlot

.travis.yml

@@ -52,7 +52,7 @@ matrix:
   include:
     - python: 2.7
       env:
-        - VERSIONS="numpy==1.12.0 matplotlib==2.0.0 scipy==0.17.0 pint==0.8 xarray==0.10.7"
+        - VERSIONS="numpy==1.12.0 matplotlib==2.0.0 scipy==0.17.0 pint==0.8 xarray==0.10.7 pandas==0.20.0"
         - TASK="coverage"
         - TEST_OUTPUT_CONTROL=""
     - python: "3.7-dev"

metpy/plots/tests/test_station_plot.py

@@ -7,6 +7,7 @@
 import matplotlib
 import matplotlib.pyplot as plt
 import numpy as np
+import pandas as pd
 import pytest
 
 from metpy.plots import (current_weather, high_clouds, nws_layout, simple_layout,
@@ -341,3 +342,21 @@ def test_barb_unit_conversion_exception(u, v):
     stnplot = StationPlot(ax, x_pos, y_pos)
     with pytest.raises(ValueError):
         stnplot.plot_barb(u, v, plot_units='knots')
+
+
+@pytest.mark.mpl_image_compare(tolerance={'1.5': 0.0, '1.4': 0.0}.get(MPL_VERSION, 0.000),
+                               savefig_kwargs={'dpi': 300}, remove_text=True)
+def test_symbol_pandas_timeseries():
+    """Test the usage of Pandas DatetimeIndex as a valid `x` input into StationPlot."""
+    pd.plotting.register_matplotlib_converters()
+    rng = pd.date_range('12/1/2017', periods=5, freq='D')
+    sc = [1, 2, 3, 4, 5]
+    ts = pd.Series(sc, index=rng)
+    fig, ax = plt.subplots()
+    y = np.ones(len(ts.index))
+    stationplot = StationPlot(ax, ts.index, y, fontsize=12)
+    stationplot.plot_symbol('C', ts, sky_cover)
+    ax.xaxis.set_major_locator(matplotlib.dates.DayLocator())
+    ax.xaxis.set_major_formatter(matplotlib.dates.DateFormatter('%-d'))
+
+    return fig