tests: make sure plot_utils.plot_load works with a single run
diff --git a/tests/test_plot_utils.py b/tests/test_plot_utils.py
index ef6f470..b44c276 100644
--- a/tests/test_plot_utils.py
+++ b/tests/test_plot_utils.py
@@ -112,3 +112,10 @@
 
         plot_utils.plot_load(runs, self.map_label, height=5)
         matplotlib.pyplot.close('all')
+
+    def test_plot_load_single_run(self):
+        """plot_utils.plot_load() can be used with a single run"""
+        run = cr2.Run()
+
+        plot_utils.plot_load([run], self.map_label)
+        matplotlib.pyplot.close('all')