diff --git a/tests/conftest.py b/tests/conftest.py
index 87287de0..03eb8cf2 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,5 +1,7 @@
+import matplotlib
 from pathlib import Path
 
+matplotlib.use("Agg")
 test_root = Path(__file__).parent
 file_root = test_root / "test_input_files"
 example_root = Path(__file__).parent.parent / "data/examples"