pdf tests: Save temporary pdfs for failed test debugging

src/tests/conftest.py

@@ -21,6 +21,8 @@
 #
 import inspect
 import os
+import re
+from pathlib import Path
 
 import pytest
 from django.core.cache import cache
@@ -28,7 +30,6 @@ from django.test import override_settings
 from django.utils import translation
 from django_scopes import scopes_disabled
 from fakeredis import FakeRedisConnection
-from hierarkey.proxy import dirty_cache_keys
 from xdist.dsession import DSession
 
 from pretix.testutils.mock import get_redis_connection
@@ -85,6 +86,7 @@ def reset_locale():
 
 @pytest.fixture(autouse=True)
 def reset_hierarkey_cache_state():
+    from hierarkey.proxy import dirty_cache_keys
     dirty_cache_keys.set(set())
 
 
@@ -143,3 +145,23 @@ def set_lock_namespaces(request):
 @pytest.fixture
 def class_monkeypatch(request, monkeypatch):
     request.cls.monkeypatch = monkeypatch
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        '--pdf-dir', action='store', help="output dir for files generated by pdf tests", type=Path
+    )
+    parser.addoption(
+        '--pdf-tmp-keep', action='store_true', help="keep the temporary directory created for pdf tests"
+    )
+
+
+@pytest.fixture
+def pdf_dir(request, tmp_path_factory):
+    dirname = re.sub('[^a-zA-Z0-9]+', '_', request.node.name).strip("_")
+    if dir := request.config.getoption('--pdf-dir'):
+        pdf_dir: Path = (dir / dirname).absolute()
+        pdf_dir.mkdir(exist_ok=True, parents=True)
+        yield pdf_dir
+    else:
+        yield tmp_path_factory.mktemp(dirname)

src/tests/plugins/badges/test_pdf.py

@@ -32,7 +32,7 @@
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under the License.
 
-import tempfile
+import logging
 from datetime import timedelta
 from decimal import Decimal
 from io import BytesIO
@@ -129,10 +129,15 @@ def asset_path(name):
     return Path(__file__).parent / "assets" / name
 
 
-def compare_pdfs(inp_a: Path | bytes, inp_b: Path | bytes):
+def compare_pdfs(pdf_dir: Path, inp_a: Path | bytes, inp_b: Path | bytes):
+    logging.info(f"Comparing pdfs, writing files to {pdf_dir}")
+
     pdf_a = pypdfium2.PdfDocument(inp_a)
     pdf_b = pypdfium2.PdfDocument(inp_b)
 
+    pdf_a.save(pdf_dir / "a.pdf")
+    pdf_a.save(pdf_dir / "b.pdf")
+
     assert len(pdf_a) == len(pdf_b)
 
     for i, (expected_page, output_page) in enumerate(zip(pdf_a, pdf_b)):
@@ -143,9 +148,8 @@ def compare_pdfs(inp_a: Path | bytes, inp_b: Path | bytes):
 
         diff = ImageChops.difference(expected_render.to_pil(), output_render.to_pil())
         if diff.getbbox():
-            with tempfile.NamedTemporaryFile(delete=False, suffix=".png") as f:
-                diff.save(f)
-            assert not diff.getbbox(), f"Page {i} differs. Diff was written to {f.name}"
+            diff.save(pdf_dir / f"{i}.png")
+            assert not diff.getbbox(), f"Page {i} differs."
 
 
 @pytest.mark.django_db
@@ -154,7 +158,7 @@ def compare_pdfs(inp_a: Path | bytes, inp_b: Path | bytes):
     "bg-mediabox-offset",
     "bg-cropbox"
 ])
-def test_generate_pdf_weird_bgs(env, case):
+def test_generate_pdf_weird_bgs(pdf_dir, env, case):
     event, order, shirt = env
     asset_folder = asset_path(case)
     with open(asset_folder / "bg.pdf", 'rb') as fi:
@@ -168,4 +172,4 @@ def test_generate_pdf_weird_bgs(env, case):
     assert ftype == 'application/pdf'
     assert buf
 
-    compare_pdfs(buf, asset_folder / "expected.pdf")
+    compare_pdfs(pdf_dir, buf, asset_folder / "expected.pdf")