change mpl backend and remove old stylesheets

Author: cadenmyers13

docs/examples/ch08NPRefinement/solutions/diffpy-cmi/fitCdSeNP.py

@@ -447,10 +447,6 @@ def plot_results(recipe, fig_name):
 
     # Change some style details of the plot
     mpl.rcParams.update(mpl.rcParamsDefault)
-    if (PWD.parent.parent.parent / "utils" / "billinge.mplstyle").exists():
-        plt.style.use(
-            str(PWD.parent.parent.parent / "utils" / "billinge.mplstyle")
-        )
 
     # Create a figure and an axis on which to plot
     fig, ax1 = plt.subplots(1, 1)

docs/examples/ch11ClusterXYZ/solutions/diffpy-cmi/fitCdSeNP.py

@@ -199,9 +199,6 @@ def plot_results(recipe, figname):
     diff = g - gcalc + diffzero
 
     mpl.rcParams.update(mpl.rcParamsDefault)
-    plt.style.use(
-        str(PWD.parent.parent.parent / "utils" / "billinge.mplstyle")
-    )
 
     fig, ax1 = plt.subplots(1, 1)
 

tests/conftest.py

@@ -4,6 +4,7 @@
 import shutil
 from pathlib import Path
 
+import matplotlib
 import pytest
 
 PROJECT_ROOT = Path(__file__).resolve().parents[1]
@@ -23,6 +24,12 @@ def tmp_examples(tmp_path_factory):
     yield tmp_examples
 
 
+@pytest.fixture(scope="session", autouse=True)
+def use_headless_matplotlib():
+    """Force matplotlib to use a headless backend during tests."""
+    matplotlib.use("Agg")
+
+
 @pytest.fixture
 def user_filesystem(tmp_path):
     base_dir = Path(tmp_path)