Add basic screenshot test

tests/test_screenshot.py

@@ -0,0 +1,22 @@
+from pathlib import Path
+
+from myterial import orange, salmon
+from rich import print
+from PIL import Image
+from brainrender import Scene
+
+def test_screenshot(tmp_path):
+    filename = "screenshot.png"
+    scene = Scene(
+        screenshots_folder=tmp_path,
+    )
+    scene.add_brain_region("TH")
+    scene.render(interactive=False, zoom=2)
+    scene.screenshot(name=filename)
+    scene.close()
+
+    test_filepath = tmp_path / filename
+    assert test_filepath.exists()
+
+    img1 = Image.open(test_filepath)
+    assert img1.size == (1600, 1200)