Cropping investigation

tests/test_crop_exercise_bottoms.py

@@ -20,7 +20,7 @@ class CropExerciseBottomsTests(unittest.TestCase):
             page = document.new_page(width=600, height=height)
             page.insert_text((80, text_y), "student answer", fontsize=16)
             if footer:
-                page.insert_text((20, height - 3), "Ex 2", fontsize=10)
+                page.insert_text((20, height - 15), "9/9", fontsize=10)
             document.save(path)
         return path
 
@@ -33,7 +33,7 @@ class CropExerciseBottomsTests(unittest.TestCase):
         self.assertEqual(records[0]["status"], "skipped-short")
         self.assertFalse(destination.exists())
 
-    def test_footer_fragment_is_ignored_for_a_large_bottom_crop(self):
+    def test_isolated_page_number_allows_a_large_bottom_crop(self):
         source = self.make_pdf("large.pdf", 400, 100)
         destination = self.root / "out" / source.name
         records = process_exercise_pdf(
@@ -45,6 +45,18 @@ class CropExerciseBottomsTests(unittest.TestCase):
             self.assertLess(result[0].rect.height, 250)
             self.assertAlmostEqual(result[0].rect.width, 600)
 
+    def test_content_in_former_ignored_bottom_strip_is_retained(self):
+        source = self.make_pdf("bottom-content.pdf", 400, 100, footer=False)
+        with pymupdf.open(source) as doc:
+            doc[0].insert_text((20, 399), "Ex 2", fontsize=10)
+            doc.save(self.root / "bottom-label.pdf")
+        records = process_exercise_pdf(
+            self.root / "bottom-label.pdf", self.root / "retained.pdf",
+            self.review, 800, dpi=150
+        )
+        self.assertEqual(records[0]["status"], "unchanged-small-crop")
+        self.assertFalse((self.root / "retained.pdf").exists())
+
     def test_crop_smaller_than_four_lines_is_not_written(self):
         source = self.make_pdf("small.pdf", 400, 330, footer=False)
         destination = self.root / "out" / source.name