TST: Use external repository for larger/more PDFs for testing (#820)

* Use submodule so that the connection is clear. Ensure that Flake8 issues of the submodule don't show up here
* As a first step, just try to get the number of pages from the non-encrypted PDFs
* Create an "external" pytest marker which allows people to deactivate tests that need the submodule

.github/workflows/github-ci.yaml

@@ -26,6 +26,8 @@ jobs:
     steps:
     - name: Checkout Code
       uses: actions/checkout@v3
+      with:
+        submodules: 'recursive'
     - name: Setup Python
       uses: actions/setup-python@v3
       with:
@@ -46,7 +48,7 @@ jobs:
         pip install .
     - name: Test with flake8
       run: |
-        flake8 . --ignore=E203,W503,W504,E,F403,F405 --exclude build
+        flake8 . --ignore=E203,W503,W504,E,F403,F405 --exclude build,sample-files
       if: matrix.python-version != '2.7'
     - name: Test with pytest
       run: |

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "sample-files"]
+	path = sample-files
+	url = https://github.com/py-pdf/sample-files

Tests/test_page.py

@@ -1,4 +1,5 @@
 import os
+import json
 
 import pytest
 
@@ -7,6 +8,30 @@
 TESTS_ROOT = os.path.abspath(os.path.dirname(__file__))
 PROJECT_ROOT = os.path.dirname(TESTS_ROOT)
 RESOURCE_ROOT = os.path.join(PROJECT_ROOT, "Resources")
+EXTERNAL_ROOT = os.path.join(PROJECT_ROOT, "sample-files")
+
+
+def get_all_sample_files():
+    with open(os.path.join(EXTERNAL_ROOT, "files.json")) as fp:
+        data = fp.read()
+    meta = json.loads(data)
+    return meta
+
+
+all_files_meta = get_all_sample_files()
+
+
+@pytest.mark.external
+@pytest.mark.parametrize(
+    "meta",
+    [m for m in all_files_meta["data"] if not m["encrypted"]],
+    ids=[m["path"] for m in all_files_meta["data"] if not m["encrypted"]],
+)
+def test_read(meta):
+    pdf_path = os.path.join(EXTERNAL_ROOT, meta["path"])
+    reader = PdfFileReader(pdf_path)
+    reader.pages[0]
+    assert len(reader.pages) == meta["pages"]
 
 
 @pytest.mark.parametrize(

docs/dev/intro.md

@@ -15,6 +15,23 @@ pip install -r requirements/dev.txt
 pytest .
 ```
 
+We have the following pytest markers defined:
+
+* `no_py27`: Flag for tests that fail under Python 2.7 only
+* `external`: Tests which use files from [the `sample-files` git submodule](https://github.com/py-pdf/sample-files)
+
+You can locally choose not to run those via `pytest -m "not external"`.
+
+## The sample-files git submodule
+The reason for having the submodule `sample-files` is that we want to keep
+the size of the PyPDF2 repository small while we also want to have an extensive
+test suite. Those two goals contradict each other.
+
+The `Resources` folder should contain a select set of core examples that cover
+most cases we typically want to test for. The `sample-files` might cover a lot
+more edge cases, the behavior we get when file sizes get bigger, different
+PDF producers.
+
 ## Tools: git and pre-commit
 
 Git is a command line application for version control. If you don't know it,

pytest.ini

@@ -1,3 +1,4 @@
 [pytest]
 markers =
-    no_py27: Flag for tests that fail under Python 2.7 only
+    no_py27: Flag for tests that fail under Python 2.7 only
+    external: Tests which use files from https://github.com/py-pdf/sample-files