Improve some documentation for tests

tests/spoof/tesseract_big_image_error.py

@@ -8,13 +8,7 @@ VERSION_STRING = '''tesseract 3.04.00
 SPOOFED: return error claiming image too big
 '''
 
-"""Simulates a Tesseract crash
-
-It isn't strictly necessary to crash the process and that has unwanted
-side effects like triggering core dumps or error reporting, logging and such.
-It's enough to dump some text to stderr and return an error code.
-
-Follows the POSIX? convention of returning 128 + signal number.
+"""Simulates an error of Tesseract failing on attempts to process large images
 
 """
 

tests/spoof/tesseract_cache.py

@@ -6,6 +6,25 @@ import shutil
 import subprocess
 
 
+"""Cache output of tesseract to speed up test suite
+
+The cache is keyed by a hash that includes the tesseract version, some of
+the command line, and the binary dump of the input file. The output file,
+stdout, and stderr are replicated on a cache hit.
+
+Page orientation checks are also cached (-psm 0 stdout)
+
+Errors and crashes are not cached.
+
+Things not checked:
+-changes to tesseract installation that don't affect --version
+
+Will fail on Tesseract 3.02.02 in "hocr" mode because it doesn't produce
+the incorrect file extension.
+
+"""
+
+
 CACHE_PATH = os.path.abspath(os.path.join(
         os.path.dirname(__file__), '..', 'cache'))
 

tests/spoof/tesseract_crash.py

@@ -10,13 +10,13 @@ VERSION_STRING = '''tesseract 3.04.00
 SPOOFED: CRASH ON OCR or -psm 0
 '''
 
-"""Simulates a Tesseract crash
+"""Simulates a Tesseract crash when asked to run OCR
 
 It isn't strictly necessary to crash the process and that has unwanted
 side effects like triggering core dumps or error reporting, logging and such.
 It's enough to dump some text to stderr and return an error code.
 
-Follows the POSIX? convention of returning 128 + signal number.
+Follows the POSIX(?) convention of returning 128 + signal number.
 
 """
 

tests/spoof/tesseract_noop.py

@@ -4,6 +4,18 @@ import img2pdf
 from PIL import Image
 
 
+"""Tesseract no-op spoof
+
+To quickly run tests where getting OCR output is not necessary.
+
+In 'hocr' mode, create a .hocr file that specifies no text found.
+
+In 'pdf' mode, convert the image to PDF using another program.
+
+In orientation check mode, report the orientation is upright.
+"""
+
+
 VERSION_STRING = '''tesseract 3.04.00
  leptonica-1.72
   libjpeg 8d : libpng 1.6.19 : libtiff 4.0.6 : zlib 1.2.5

tests/test_main.py

@@ -614,6 +614,8 @@ def test_stdin(spoof_tesseract_noop):
     input_file = _infile('francais.pdf')
     output_file = _outfile('test_stdin.pdf')
 
+    # Runs: cat testfile.pdf | ocrmypdf - output.pdf
+
     p1_args = ['cat', input_file]
     p1 = Popen(p1_args, close_fds=True, stdin=DEVNULL, stdout=PIPE)