Update testing env to include PendingDeprecation warnings (#3114)

Closes #2716 

According to the official python docs, `PendingDeprecation` warnings are
[ignored by
default](https://docs.python.org/3/library/exceptions.html#PendingDeprecationWarning)
unless [Python Development
Mode](https://docs.python.org/3/library/devmode.html) is enabled (done
either through the `-Xdev` or `-Wd` flags when invoking `python` or by
setting the environment variable `PYTHONDEVMODE=1`).

This PR sets the `tox` environment to run using dev mode with the
`PYTHONDEVMODE` env var.

Author: kaelynj

docs/guides/circuit-library.ipynb

@@ -56,7 +56,11 @@
    "cell_type": "code",
    "execution_count": 1,
    "id": "a846a845-7ac5-4c92-b124-d2b90a773ba2",
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "ignore-warnings"
+    ]
+   },
    "outputs": [
     {
      "data": {

docs/guides/qiskit-addons-mpf-get-started.ipynb

@@ -157,7 +157,11 @@
    "cell_type": "code",
    "execution_count": 3,
    "id": "d2f308be-2c13-475c-b9a7-390883a620bc",
-   "metadata": {},
+   "metadata": {
+    "tags": [
+        "ignore-warnings"
+    ]
+   },
    "outputs": [
     {
      "name": "stdout",

scripts/nb-tester/qiskit_docs_notebook_tester/config.py

@@ -28,6 +28,7 @@
 # Import with underscores to avoid interfering with user-facing code.
 from matplotlib import set_loglevel as _set_mpl_loglevel
 
+
 # See https://github.com/matplotlib/matplotlib/issues/23326#issuecomment-1164772708
 _set_mpl_loglevel("critical")
 """
@@ -73,6 +74,12 @@ def get_notebook_jobs(args: argparse.Namespace) -> Iterator[NotebookJob]:
                     )
                 continue
 
+            warning_filter = ""
+            if config.check_pending_deprecations:
+                warning_filter = "import warnings as _warnings \
+                \n_warnings.simplefilter('default', category=PendingDeprecationWarning)"
+            pre_execute_code = PRE_EXECUTE_CODE + warning_filter
+
             patch = config.get_patch_for_group(group)
 
             if patch and not "# nb-tester: allow-write" in patch:
@@ -84,7 +91,7 @@ def get_notebook_jobs(args: argparse.Namespace) -> Iterator[NotebookJob]:
 
             yield NotebookJob(
                 path=Path(path),
-                pre_execute_code=PRE_EXECUTE_CODE,
+                pre_execute_code=pre_execute_code,
                 backend_patch=patch,
                 cell_timeout=config.cell_timeout,
                 write=write,
@@ -96,6 +103,7 @@ class Config:
     cli_filenames: list[Path]
     cell_timeout: int
     test_strategy: str
+    check_pending_deprecations: bool
     write: bool
     groups: list[dict]
 
@@ -133,6 +141,7 @@ def from_args(cls, args: argparse.Namespace) -> Config:
                 cli_filenames=cli_filenames,
                 cell_timeout=args.cell_timeout,
                 test_strategy="custom",
+                check_pending_deprecations=args.check_pending_deprecations,
                 write=args.write,
                 groups=groups,
             )
@@ -150,16 +159,14 @@ def from_args(cls, args: argparse.Namespace) -> Config:
             {"name": key, **value} for key, value in config_file["groups"].items()
         ]
         test_strategy = args.test_strategy or config_file["default-strategy"]
-        cell_timeout = (
-            args.cell_timeout or
-            config_file.get("test-strategies", {})
-            .get(test_strategy, {})
-            .get("timeout", None)
-        )
+        cell_timeout = args.cell_timeout or config_file.get("test-strategies", {}).get(
+            test_strategy, {}
+        ).get("timeout", None)
         return cls(
             cli_filenames=args.filenames,
             cell_timeout=cell_timeout,
             test_strategy=test_strategy,
+            check_pending_deprecations=args.check_pending_deprecations,
             write=args.write,
             groups=groups,
         )
@@ -261,4 +268,9 @@ def get_parser() -> argparse.ArgumentParser:
             "useful to set if your patch does not use QiskitRuntimeService"
         ),
     )
+    parser.add_argument(
+        "--check-pending-deprecations",
+        action="store_true",
+        help="Include checking for PendingDeprecationWarnings in notebook outputs",
+    )
     return parser

tox.ini

@@ -8,7 +8,7 @@ deps =
   -e scripts/nb-tester
   -r scripts/nb-tester/requirements.txt
 setenv = PYDEVD_DISABLE_FILE_VALIDATION=1
-commands = test-docs-notebooks {posargs} --config-path scripts/config/notebook-testing.toml
+commands = test-docs-notebooks {posargs} --check-pending-deprecations --config-path scripts/config/notebook-testing.toml
 
 [testenv:{lint,fix}]
 deps =