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
+
+# 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
+    return None

[epoger, 2013/05/09 19:19:39]

This could raise an Exception, thus halting execution with an error status.  If
you give the Exception a description, it'll even be logged for you...

[scroggo, 2013/05/13 15:43:26]

Done.

+
+def main():
+    # Use the directory of this file as the out directory
+    file_dir = os.path.dirname(__file__)
+    file_dir = os.path.abspath(file_dir)

[epoger, 2013/05/09 19:19:39]

how about just:

file_dir = os.path.abspath(os.path.dirname(__file__))

[scroggo, 2013/05/13 15:43:26]

Done.

+
+    trunk_dir = os.path.normpath(os.path.join(file_dir, '../../'))
+
+    # Find the binary
+    skimage_binary = PickBinaryPath(trunk_dir)
+
+    success = False;
+    if (skimage_binary != None):
+        try:
+            print "Running " + skimage_binary
+            # Run skimage twice, first to create an expectations file, and then
+            # 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)
+            success = True;
+        except subprocess.CalledProcessError as e:

[epoger, 2013/05/09 19:19:39]

Do you need to catch CalledProcessError?  What if you just allowed the Exception
to get thrown all the way to the calling shell?

[scroggo, 2013/05/13 15:43:26]

I do not. I caught the error to give a cleaner error message, but cleaner also
means less information, so I've updated the code to all the exception to get
thrown to the shell.

+            print skimage_binary + " failed with error code " + str(e.returncode)
+    else:
+        print "Could not find skimage binary!"
+        print "Did you forget to build tools project?"
+
+    if success:
+        print "Self tests succeeded!"
+        sys.exit(0)
+    print "Self tests failed!"
+    sys.exit(-1)
+
+main()