CLN/DOC: fix test_register_entrypoint (#46302)

Author: graingert

asv_bench/benchmarks/plotting.py

@@ -1,9 +1,14 @@
-import importlib
+import contextlib
+import importlib.machinery
+import importlib.util
+import os
+import pathlib
 import sys
+import tempfile
+from unittest import mock
 
 import matplotlib
 import numpy as np
-import pkg_resources
 
 from pandas import (
     DataFrame,
@@ -111,22 +116,49 @@ class BackendLoading:
     warmup_time = 0
 
     def setup(self):
-        dist = pkg_resources.get_distribution("pandas")
-        spec = importlib.machinery.ModuleSpec("my_backend", None)
-        mod = importlib.util.module_from_spec(spec)
+        mod = importlib.util.module_from_spec(
+            importlib.machinery.ModuleSpec("pandas_dummy_backend", None)
+        )
         mod.plot = lambda *args, **kwargs: 1
 
-        backends = pkg_resources.get_entry_map("pandas")
-        my_entrypoint = pkg_resources.EntryPoint(
-            "pandas_plotting_backend", mod.__name__, dist=dist
-        )
-        backends["pandas_plotting_backends"][mod.__name__] = my_entrypoint
-        for i in range(10):
-            backends["pandas_plotting_backends"][str(i)] = my_entrypoint
-        sys.modules["my_backend"] = mod
+        with contextlib.ExitStack() as stack:
+            stack.enter_context(
+                mock.patch.dict(sys.modules, {"pandas_dummy_backend": mod})
+            )
+            tmp_path = pathlib.Path(stack.enter_context(tempfile.TemporaryDirectory()))
+
+            sys.path.insert(0, os.fsdecode(tmp_path))
+            stack.callback(sys.path.remove, os.fsdecode(tmp_path))
+
+            dist_info = tmp_path / "my_backend-0.0.0.dist-info"
+            dist_info.mkdir()
+            (dist_info / "entry_points.txt").write_bytes(
+                b"[pandas_plotting_backends]\n"
+                b"my_ep_backend = pandas_dummy_backend\n"
+                b"my_ep_backend0 = pandas_dummy_backend\n"
+                b"my_ep_backend1 = pandas_dummy_backend\n"
+                b"my_ep_backend2 = pandas_dummy_backend\n"
+                b"my_ep_backend3 = pandas_dummy_backend\n"
+                b"my_ep_backend4 = pandas_dummy_backend\n"
+                b"my_ep_backend5 = pandas_dummy_backend\n"
+                b"my_ep_backend6 = pandas_dummy_backend\n"
+                b"my_ep_backend7 = pandas_dummy_backend\n"
+                b"my_ep_backend8 = pandas_dummy_backend\n"
+                b"my_ep_backend9 = pandas_dummy_backend\n"
+            )
+            self.stack = stack.pop_all()
+
+    def teardown(self):
+        self.stack.close()
 
     def time_get_plot_backend(self):
-        _get_plot_backend("my_backend")
+        # finds the first my_ep_backend
+        _get_plot_backend("my_ep_backend")
+
+    def time_get_plot_backend_fallback(self):
+        # iterates through all the my_ep_backend[0-9] before falling back
+        # to importlib.import_module
+        _get_plot_backend("pandas_dummy_backend")
 
 
 from .pandas_vb_common import setup  # noqa: F401 isort:skip

pandas/plotting/_core.py

@@ -1769,7 +1769,7 @@ def _load_backend(backend: str) -> types.ModuleType:
     ----------
     backend : str
         The identifier for the backend. Either an entrypoint item registered
-        with pkg_resources, "matplotlib", or a module name.
+        with importlib.metadata, "matplotlib", or a module name.
 
     Returns
     -------

pandas/tests/plotting/test_backend.py

@@ -1,7 +1,6 @@
 import sys
 import types
 
-import pkg_resources
 import pytest
 
 import pandas.util._test_decorators as td
@@ -45,40 +44,28 @@ def test_backend_can_be_set_in_plot_call(monkeypatch, restore_backend):
     assert df.plot(backend="pandas_dummy_backend") == "used_dummy"
 
 
-@td.skip_if_no_mpl
-def test_register_entrypoint(restore_backend):
-
-    dist = pkg_resources.get_distribution("pandas")
-    if dist.module_path not in pandas.__file__:
-        # We are running from a non-installed pandas, and this test is invalid
-        pytest.skip("Testing a non-installed pandas")
-
-    mod = types.ModuleType("my_backend")
-    mod.plot = lambda *args, **kwargs: 1
+def test_register_entrypoint(restore_backend, tmp_path, monkeypatch):
+    monkeypatch.syspath_prepend(tmp_path)
+    monkeypatch.setitem(sys.modules, "pandas_dummy_backend", dummy_backend)
 
-    backends = pkg_resources.get_entry_map("pandas")
-    my_entrypoint = pkg_resources.EntryPoint(
-        "pandas_plotting_backend", mod.__name__, dist=dist
+    dist_info = tmp_path / "my_backend-0.0.0.dist-info"
+    dist_info.mkdir()
+    # entry_point name should not match module name - otherwise pandas will
+    # fall back to backend lookup by module name
+    (dist_info / "entry_points.txt").write_bytes(
+        b"[pandas_plotting_backends]\nmy_ep_backend = pandas_dummy_backend\n"
     )
-    backends["pandas_plotting_backends"]["my_backend"] = my_entrypoint
-    # TODO: the docs recommend importlib.util.module_from_spec. But this works for now.
-    sys.modules["my_backend"] = mod
-
-    result = pandas.plotting._core._get_plot_backend("my_backend")
-    assert result is mod
 
-    # TODO(GH#27517): https://github.com/pandas-dev/pandas/issues/27517
-    # Remove the td.skip_if_no_mpl
-    with pandas.option_context("plotting.backend", "my_backend"):
-        result = pandas.plotting._core._get_plot_backend()
+    assert pandas.plotting._core._get_plot_backend("my_ep_backend") is dummy_backend
 
-    assert result is mod
+    with pandas.option_context("plotting.backend", "my_ep_backend"):
+        assert pandas.plotting._core._get_plot_backend() is dummy_backend
 
 
-def test_setting_backend_without_plot_raises():
+def test_setting_backend_without_plot_raises(monkeypatch):
     # GH-28163
     module = types.ModuleType("pandas_plot_backend")
-    sys.modules["pandas_plot_backend"] = module
+    monkeypatch.setitem(sys.modules, "pandas_plot_backend", module)
 
     assert pandas.options.plotting.backend == "matplotlib"
     with pytest.raises(

setup.cfg

@@ -125,6 +125,8 @@ per-file-ignores =
     doc/make.py:PDF008
     # import from pandas._testing
     pandas/testing.py:PDF014
+    # can't use fixtures in asv
+    asv_bench/*:PDF016
 
 
 [flake8-rst]