LayoutComparator

Layout Comparator

Layout Comparator is responsible for comparing collected screenshot of page with pattern. This is default comparator for screen resource.

Can be rebased from report.

Module name: layout

Resource name: screen

Parameters

Parameter	Value	Description	Mandatory
pixelThreshold	int (equal or greater than 0)	The value to set the error threshold in pixels e.g if difference between photos is smaller or equal to pixelThreshold, the test will pass. In case of difference is bigger than pixelThreshold, the test will fail.	no
percentageThreshold	double (between 0 and 100)	It works as pixelThreshold but values are in percentages	no
fuzz	int (between 0 and 100)	A percentage value that describes the maximum color difference between pixels on the pattern and collected screenshot images. This option allows to filter out image rendering issues like AEM image rendition differences not visible to the human eye.	no

Each of these parameters should be used with caution. It's recommended to test how these parameters change the behavior of your tests before introducing them to your test suite permanently.

When you provide pixelThreshold and percentageThreshold test will pass only if pixel difference is smaller or equal than pixelThreshold and percentage difference is smaller or equal than percentageThreshold.

Example Usage

<?xml version="1.0" encoding="UTF-8" ?>
<suite name="test-suite" company="cognifide" project="project">
    <test name="layout-compare-test">
        <collect>
            ...
            <screen />
            ...
        </collect>
        <compare>
            ...
            <screen comparator="layout" pixelThreshold="2500" percentageThreshold="0.5" fuzz="30"/>
            ...
        </compare>
        <urls>
        ...
        </urls>
    </test>
    ...
    <reports>
        ...
    </reports>
</suite>

Fast pre-comparison

Since AET 1.3 fast comparison of screenshots will be implemented. Taken screenshot MD5 will be matched against current pattern. If hashes will be the same, screenshot will be treated as one without differences and no further comparison will be performed.