Run pixel tests via automated script.

On origin/master, we only have .ppm format support, so the
expected output files would take up a lot of space. Hence,
this may not get going until XFA hits with its .png
support.

Nor is there a good way to diff these; XFA provides this
for .png as well.

But this will provide at least one automated test to ensure
that we've got non-blank output, at least for one trivially
simple case.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/926173002
diff --git a/testing/resources/pixel/font_size.in b/testing/resources/pixel/font_size.in
new file mode 100644
index 0000000..c4e21e2
--- /dev/null
+++ b/testing/resources/pixel/font_size.in
@@ -0,0 +1,62 @@
+{{header}}
+{{object 1 0}} <<
+  /Type /Catalog
+  /Pages 2 0 R
+>>
+{{object 2 0}} <<
+  /Type /Pages
+  /MediaBox [ 0 0 100 400 ]
+  /Count 1
+  /Kids [ 3 0 R ]
+>>
+endobj
+{{object 3 0}} <<
+  /Type /Page
+  /Parent 2 0 R
+  /Resources <<
+    /Font <<
+      /F1 4 0 R
+    >>
+  >>
+  /Contents 6 0 R
+>>
+endobj
+{{object 4 0}} <<
+  /Type /Font
+  /Subtype /Type1
+  /BaseFont /Times-Roman
+>>
+endobj
+{{object 6 0}} <<
+>>
+stream
+BT
+20 0 Td
+0 20 Td /F1 0 Tf (Size 0) Tj
+0 20 Td /F1 1 Tf (Size 1) Tj
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+ET
+endstream
+endobj
+{{xref}}
+trailer <<
+  /Root 1 0 R
+>>
+{{startxref}}
+%%EOF
diff --git a/testing/resources/pixel/font_size_expected.pdf.0.ppm b/testing/resources/pixel/font_size_expected.pdf.0.ppm
new file mode 100644
index 0000000..a433b39
--- /dev/null
+++ b/testing/resources/pixel/font_size_expected.pdf.0.ppm
Binary files differ
diff --git a/testing/tools/run_pixel_tests.py b/testing/tools/run_pixel_tests.py
new file mode 100755
index 0000000..07ea7d8
--- /dev/null
+++ b/testing/tools/run_pixel_tests.py
@@ -0,0 +1,99 @@
+#!/usr/bin/env python
+# Copyright 2015 The PDFium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import optparse
+import os
+import re
+import subprocess
+import sys
+
+# Nomenclature:
+#   x_root - "x"
+#   x_filename - "x.ext"
+#   x_path - "path/to/a/b/c/x.ext"
+#   c_dir - "path/to/a/b/c"
+
+def generate_and_test(input_filename, source_dir, working_dir,
+                      fixup_path, pdfium_test_path):
+  input_root, _ = os.path.splitext(input_filename)
+  input_path = os.path.join(source_dir, input_root + '.in')
+  pdf_path = os.path.join(working_dir, input_root + '.pdf')
+  actual_path_template = os.path.join(working_dir, input_root + '.pdf.%d.ppm')
+  expected_path_template = os.path.join(source_dir,
+                                        input_root + '_expected.pdf.%d.ppm')
+  try:
+    subprocess.check_call(
+        [fixup_path, '--output-dir=' + working_dir, input_path])
+    subprocess.check_call([pdfium_test_path, '--ppm', pdf_path])
+    i = 0;
+    while True:
+      expected_path = expected_path_template % i;
+      actual_path = actual_path_template % i;
+      if not os.path.exists(expected_path):
+        break
+      subprocess.check_call(['diff', expected_path, actual_path])
+      i += 1
+  except subprocess.CalledProcessError as e:
+    print "FAILURE: " + input_filename + "; " + str(e)
+
+def main():
+  parser = optparse.OptionParser()
+  parser.add_option('--build-dir', default=os.path.join('out', 'Debug'),
+                    help='relative path from the base source directory')
+  options, args = parser.parse_args()
+
+  # Expect |my_dir| to be .../pdfium/testing/tools.
+  my_dir = os.path.dirname(os.path.realpath(__file__))
+  testing_dir = os.path.dirname(my_dir)
+  pdfium_dir = os.path.dirname(testing_dir)
+  if (os.path.basename(my_dir) != 'tools' or
+      os.path.basename(testing_dir) != 'testing'):
+    print 'Confused, can not find pdfium root directory, aborting.'
+    return 1
+
+  # Other scripts are found in the same directory as this one.
+  fixup_path = os.path.join(my_dir, 'fixup_pdf_template.py')
+
+  # test files are in .../pdfium/testing/resources/pixel.
+  source_dir = os.path.join(testing_dir, 'resources', 'pixel')
+
+  # Find path to build directory.  This depends on whether this is a
+  # standalone build vs. a build as part of a chromium checkout. For
+  # standalone, we expect a path like .../pdfium/out/Debug, but for
+  # chromium, we expect a path like .../src/out/Debug two levels
+  # higher (to skip over the third_party/pdfium path component under
+  # which chromium sticks pdfium).
+  base_dir = pdfium_dir
+  one_up_dir = os.path.dirname(base_dir)
+  two_up_dir = os.path.dirname(one_up_dir)
+  if (os.path.basename(two_up_dir) == 'src' and
+      os.path.basename(one_up_dir) == 'third_party'):
+    base_dir = two_up_dir
+  build_dir = os.path.join(base_dir, options.build_dir)
+
+  # Compiled binaries are found under the build path.
+  pdfium_test_path = os.path.join(build_dir, 'pdfium_test')
+  if sys.platform.startswith('win'):
+    pdfium_test_path = pdfium_test_path + '.exe'
+  # TODO(tsepez): Mac may require special handling here.
+
+  # Place generated files under the build directory, not source directory.
+  gen_dir = os.path.join(build_dir, 'gen', 'pdfium')
+  working_dir = os.path.join(gen_dir, 'testing', 'pixel')
+  if not os.path.exists(working_dir):
+    os.makedirs(working_dir)
+
+  input_file_re = re.compile('^[a-zA-Z0-9_.]+[.]in$')
+  for input_filename in os.listdir(source_dir):
+    if input_file_re.match(input_filename):
+      input_path = os.path.join(source_dir, input_filename)
+      if os.path.isfile(input_path):
+        generate_and_test(input_filename, source_dir, working_dir,
+                          fixup_path, pdfium_test_path)
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())