client/cros/video/bp_image_comparer.py

# Copyright (c) 2014 The Chromium OS 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 logging, time
from autotest_lib.client.cros.video import bp_http_client, method_logger


class BpImageComparer(object):
    """
    Encapsulates the BioPic image comparison strategy.

    """


    @method_logger.log
    def __init__(self, project_name, contact_email, wait_time_btwn_comparisons):
        """
        Initializes the underlying bp client.

        @param project_name: string, name of test run project to view results.
        @param contact_email: string, email to receive test results on failure.
        @param wait_time_btwn_comparisons: int, time in seconds to wait between
                                           two consecutive pair of calls to
                                           upload reference and test images.
                                           If we upload without a break, biopic
                                           server could get overwhelmed and
                                           throw an exception.

        """
        self.bp_client = bp_http_client.BiopicClient(project_name)
        self.test_run = self.bp_client.CreateTestRun(contact_email)
        self.wait_time_btwn_comparisons = wait_time_btwn_comparisons


    def __enter__(self):
        """
         Enables BpImageComparer to be used with the 'with' construct.

         Using this class with the 'with' construct guarantees EndTestRun will
         be called.

         @returns this current object.

        """
        return self


    @property
    def id(self):
        """
        Returns the id of the testrun.

        """
        return self.test_run['testrun_id']


    @method_logger.log
    def compare(self, golden_image_paths, test_run_image_paths):
        """
        Compares a test image with a known reference image.

        Uses http_client interface to communicate with biopic service.

        @param golden_image_paths: path, complete path to golden image.
        @param test_run_image_paths: path, complete path to test image.

        @raises whatever biopic http interface raises.

        @returns a list of dictionaries containing test results.

        """
        if type(golden_image_paths) is not list:
            golden_image_paths = [golden_image_paths]

        if type(test_run_image_paths) is not list:
            test_run_image_paths = [test_run_image_paths]

        upload_results = []

        for gimage, timage in zip(golden_image_paths, test_run_image_paths):
            self.bp_client.UploadGoldenImage(self.id, gimage)
            res = self.bp_client.UploadRunImage(self.id, timage)

            logging.debug("*** Biopic Upload Results:\n")
            logging.debug(res)

            upload_results.append(res)
            time.sleep(self.wait_time_btwn_comparisons)

        return upload_results


    def complete(self):
        """
        Completes the test run.

        Biopic service requires its users to end the test run when finished.

        """
        self.bp_client.EndTestRun(self.id)


    def __exit__(self, exc_type, exc_val, exc_tb):
        """
        Ends the test run. Meant to be used with the 'with' construct.

        """
        self.complete()