TST: Explicitly set Dejavu Sans font for testing

Author: has2k1

plotnine/themes/theme.py

@@ -22,10 +22,10 @@
 
 # All complete themes are initiated with these rcparams. They
 # can be overridden.
-default_rcparams = {
+DEFAULT_RCPARAMS = {
     "axes.axisbelow": "True",
     "font.sans-serif": [
-        # "Helvetica",
+        "Helvetica",
         "DejaVu Sans",  # MPL ships with this one
         "Avant Garde",
         "Computer Modern Sans serif",
@@ -225,7 +225,7 @@ def __init__(
         self.complete = complete
 
         if complete:
-            self._rcParams = deepcopy(default_rcparams)
+            self._rcParams = deepcopy(DEFAULT_RCPARAMS)
         else:
             self._rcParams = {}
 

tests/conftest.py

@@ -11,10 +11,16 @@
 from matplotlib.testing.compare import compare_images
 
 from plotnine import ggplot, theme
+from plotnine.themes.theme import DEFAULT_RCPARAMS
 
 TOLERANCE = 2  # Default tolerance for the tests
 DPI = 72  # Default DPI for the tests
 
+# To get uniform test images, we use fonts that ship with matplotlib
+DEFAULT_RCPARAMS["font.monospace"] = ["Dejavu Sans Mono"]
+DEFAULT_RCPARAMS["font.sans-serif"] = ["Dejavu Sans"]
+DEFAULT_RCPARAMS["font.serif"] = ["Dejavu Serif"]
+
 # This partial theme modifies all themes that are used in
 # the test. It is limited to setting the size of the test
 # images Should a test require a larger or smaller figure