Create a self test for skimage.

tools/tests/skimage_self_test.py

+#!/usr/bin/env python
+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Self-test for skimage.
+
+import os
+import subprocess
+import sys
+
+class BinaryNotFoundException(Exception):
+    def __str__ (self):
+        return "Could not find binary!\nDid you forget to build the tools project?\n" \

[epoger, 2013/05/14 15:24:45]

or, I think this will also appease the Python interpreter:

return ("Part 1 of string\n"
        "Part 2 of string")

[scroggo, 2013/05/14 17:49:38]

Done.

+                 + "Self tests failed"
+
+# Find a path to the binary to use. Iterates through a list of possible
+# locations the binary may be.
+def PickBinaryPath(base_dir):
+    POSSIBLE_BINARY_PATHS = [
+        'out/Debug/skimage',
+        'out/Release/skimage',
+        'xcodebuild/Debug/skimage',
+        'xcodebuild/Release/skimage',
+    ]
+    for binary in POSSIBLE_BINARY_PATHS:
+        binary_full_path = os.path.join(base_dir, binary)
+        if (os.path.exists(binary_full_path)):
+            return binary_full_path
+    raise BinaryNotFoundException
+
+def main():
+    # Use the directory of this file as the out directory
+    file_dir = os.path.abspath(os.path.dirname(__file__))
+
+    trunk_dir = os.path.normpath(os.path.join(file_dir, os.pardir, os.pardir))
+
+    # Find the binary
+    skimage_binary = PickBinaryPath(trunk_dir)
+
+    print "Running " + skimage_binary
+    # Run skimage twice, first to create an expectations file, and then

[epoger, 2013/05/14 15:24:45]

IMHO, this would be easier to read with a newline before each comment line.

[scroggo, 2013/05/14 17:49:38]

Done.

+    # comparing to it.
+    # Both commands will run the binary, reading from resources.
+    cmd_line = [skimage_binary]
+    resources_dir = os.path.join(trunk_dir, 'resources')
+    cmd_line.extend(["-r", resources_dir])
+    # Create the expectations file
+    results_dir = os.path.join(file_dir, "skimage")
+    create_expectations_cmd = cmd_line + ["--createExpectationsPath", results_dir]
+    subprocess.check_call(create_expectations_cmd)
+    # Now read from the expectations file
+    results_file = os.path.join(results_dir, "results.json")
+    check_expectations_cmd = cmd_line + ["--readExpectationsPath", results_file]
+    subprocess.check_call(check_expectations_cmd)
+    print "Self tests succeeded!"
+
+if __name__ == "__main__":
+    main()