Introduce tests for redaction to make changes easier

froide/helper/redaction.py

@@ -81,7 +81,11 @@ def try_redacting_file(pdf_file, outpath, instructions):
             if rewritten_pdf_file is None:
                 # Possibly encrypted with password, let's just try it anyway
                 rewritten_pdf_file = pdf_file
-            return _redact_file(rewritten_pdf_file, outpath, instructions)
+
+            output_filename = os.path.join(outpath, "final.pdf")
+            with open(output_filename, "wb") as output_file:
+                _redact_file(rewritten_pdf_file, output_file, instructions)
+            return output_filename
         except PDFException as e:
             tries += 1
             if tries > 2:
@@ -98,7 +102,7 @@ def try_redacting_file(pdf_file, outpath, instructions):
             pdf_file = next_pdf_file
 
 
-def _redact_file(pdf_file, outpath, instructions, tries=0):
+def _redact_file(pdf_file, output_file, instructions):
     dpi = 300
     load_invisible_font()
     output = PdfWriter()
@@ -149,11 +153,7 @@ def get_page_iterator(page_instructions, image_generator):
             raise PDFException(e, "rewrite") from None
 
         output.add_page(page)
-
-    output_filename = os.path.join(outpath, "final.pdf")
-    with open(output_filename, "wb") as f:
-        output.write(f)
-    return output_filename
+    output.write(output_file)
 
 
 def get_redacted_page(image_filename, instr, dpi):

froide/helper/tests/test_redaction.py

@@ -0,0 +1,73 @@
+import os
+from io import BytesIO
+from pathlib import Path
+from unittest import TestCase
+
+import pytest
+
+from froide.helper.redaction import _redact_file
+
+redaction_test_data_path = (
+    Path(os.path.dirname(os.path.realpath(__file__))) / "testdata" / "redaction"
+)
+hello_world_pdf_path = redaction_test_data_path / "minimal_hello_world.pdf"
+hello_world_pdf_empty_instructions_redacted_path = (
+    redaction_test_data_path / "minimal_hello_world_empty_instructions_redacted.pdf"
+)
+hello_world_pdf_right_halve_redacted_path = (
+    redaction_test_data_path / "minimal_hello_world_right_halve_redacted.pdf"
+)
+
+
+def get_file_content(file):
+    file.seek(0)
+    return file.read()
+
+
+class Test(TestCase):
+    def setUp(self):
+        self.input = hello_world_pdf_path.open("rb", buffering=0)
+        self.expected = hello_world_pdf_empty_instructions_redacted_path.read_bytes()
+
+    def tearDown(self):
+        self.input.close()
+
+    @pytest.mark.asyncio(loop_scope="session")
+    def test__redact_file_empty_instructions(self):
+        in_memory_outfile = BytesIO()
+        empty_instructions = {"pages": [{"width": 1, "rects": []}]}
+
+        _redact_file(self.input, in_memory_outfile, empty_instructions)
+
+        self.assertEqual(
+            hello_world_pdf_empty_instructions_redacted_path.read_bytes(),
+            get_file_content(in_memory_outfile),
+        )
+
+    @pytest.mark.asyncio(loop_scope="session")
+    def test__redact_file_right_halve_rect_instructions(self):
+        in_memory_outfile = BytesIO()
+        right_halve = (150, 0, 300, 144)
+        text_position = (175, 72, 72, 10)
+        instructions = {
+            "pages": [
+                {
+                    "width": 300,
+                    "rects": [right_halve],
+                    "texts": [
+                        {
+                            "text": "right halve redacted",
+                            "fontSize": "6px",
+                            "pos": text_position,
+                        }
+                    ],
+                }
+            ]
+        }
+
+        _redact_file(self.input, in_memory_outfile, instructions)
+
+        self.assertEqual(
+            hello_world_pdf_right_halve_redacted_path.read_bytes(),
+            get_file_content(in_memory_outfile),
+        )

froide/helper/tests/testdata/redaction/README.md

@@ -0,0 +1,7 @@
+# Minimal PDF
+
+## minimal_hello_world.pdf
+It's from https://brendanzagaeski.appspot.com/0004.html under MIT License.
+License: ./minimal_hello_world_license.txt
+
+Other redaction test pdf's in this folder are derived from it and share the license.

froide/helper/tests/testdata/redaction/minimal_hello_world_license.txt

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Brendan Zagaeski
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.