New tests support old and new ipython

lib/matplotlib/testing/__init__.py

@@ -181,8 +181,16 @@ def _has_tex_package(package):
         return False
 
 
-def ipython_in_subprocess(requested_backend_or_gui_framework, expected_backend):
-    pytest.importorskip("IPython")
+def ipython_in_subprocess(
+    requested_backend_or_gui_framework,
+    expected_backend_old_ipython,  # IPython < 8.24
+    expected_backend_new_ipython,  # IPython >= 8.24
+):
+    IPython = pytest.importorskip("IPython")
+    if IPython.version_info[:2] >= (8, 24):
+        expected_backend = expected_backend_new_ipython
+    else:
+        expected_backend = expected_backend_old_ipython
 
     code = ("import matplotlib as mpl, matplotlib.pyplot as plt;"
             "fig, ax=plt.subplots(); ax.plot([1, 3, 2]); mpl.get_backend()")
@@ -196,5 +204,5 @@ def ipython_in_subprocess(requested_backend_or_gui_framework, expected_backend):
         check=True,
         capture_output=True,
     )
-    
+
     assert proc.stdout.strip() == f"Out[1]: '{expected_backend}'"

lib/matplotlib/testing/__init__.pyi

@@ -49,5 +49,6 @@ def _check_for_pgf(texsystem: str) -> bool: ...
 def _has_tex_package(package: str) -> bool: ...
 def ipython_in_subprocess(
     requested_backend_or_gui_framework: str,
-    expected_backend: str,
+    expected_backend_old_ipython: str,
+    expected_backend_new_ipython: str,
 ) -> None: ...

lib/matplotlib/tests/test_backend_inline.py

@@ -30,9 +30,14 @@ def test_ipynb():
     errors = [output for cell in nb.cells for output in cell.get("outputs", [])
               if output.output_type == "error"]
     assert not errors
-
+
+    import IPython
+    if IPython.version_info[:2] >= (8, 24):
+        expected_backend = "inline"
+    else:
+        expected_backend = "module://matplotlib_inline.backend_inline"
     backend_outputs = nb.cells[2]["outputs"]
-    assert backend_outputs[0]["data"]["text/plain"] == "'inline'"
+    assert backend_outputs[0]["data"]["text/plain"] == f"'{expected_backend}'"
 
     image = nb.cells[1]["outputs"][1]["data"]
     assert image["text/plain"] == "<Figure size 300x200 with 1 Axes>"

lib/matplotlib/tests/test_backend_macosx.py

@@ -48,4 +48,4 @@ def new_choose_save_file(title, directory, filename):
 
 def test_ipython():
     from matplotlib.testing import ipython_in_subprocess
-    ipython_in_subprocess("osx", "macosx")
+    ipython_in_subprocess("osx", "MacOSX", "macosx")

lib/matplotlib/tests/test_backend_nbagg.py

@@ -30,6 +30,11 @@ def test_ipynb():
     errors = [output for cell in nb.cells for output in cell.get("outputs", [])
               if output.output_type == "error"]
     assert not errors
-
+
+    import IPython
+    if IPython.version_info[:2] >= (8, 24):
+        expected_backend = "notebook"
+    else:
+        expected_backend = "nbAgg"
     backend_outputs = nb.cells[2]["outputs"]
-    assert backend_outputs[0]["data"]["text/plain"] == "'notebook'"
+    assert backend_outputs[0]["data"]["text/plain"] == f"'{expected_backend}'"

lib/matplotlib/tests/test_backend_qt.py

@@ -378,4 +378,4 @@ def custom_handler(signum, frame):
 
 def test_ipython():
     from matplotlib.testing import ipython_in_subprocess
-    ipython_in_subprocess("qt", "qtagg")
+    ipython_in_subprocess("qt", "QtAgg", "qtagg")

lib/matplotlib/tests/test_backend_tk.py

@@ -265,4 +265,4 @@ def test_figure(master):
 
 def test_ipython():
     from matplotlib.testing import ipython_in_subprocess
-    ipython_in_subprocess("tk", "tkagg")
+    ipython_in_subprocess("tk", "TkAgg", "tkagg")