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PONeed help understanding difference in raw image binary data for PHPUnit test
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copied!<p>So I wrote a Unit Test to compare cropped images (using imagemagick) in PHP. The test works, but i've been running into problems when it comes to comparing a large number of images at a time. Depending on the time the image is created at, each image receives a timestamp that is embedded directly into the raw data. I've been using a regular expression to pull out that timestamp right before comparing the files but it appears as though every once in a while, one of the image files will have additional raw data in it even though they're exactly the same. </p> <p>To give an example, here's the result from one of my tests (note, i'm comparing the binary data of the images as a string):</p> <blockquote> <p>ImageTest::testAutoCrop</p> <p>Failed asserting that two strings are equal.</p> <p>--- Expected</p> <p>+++ Actual</p> <p>@@ @@</p> <p>?n??m?</p> <p>-?F sO=f??????????^???????w??></p> <pre><code> ?(???/o????M)???o%tEXt??%tEXt </code></pre> <p>+?F sO=f??????????^???????w??></p> <pre><code> ?(???/o????M)???o%tEXt </code></pre> </blockquote> <p>As you can see....the only difference between these two files is that the expected image has this additional string in it: "?%tEXt".</p> <p>Can someone help me understand what this random piece of data represents? That will help me figure out how to modify my unit test so that issues like this won't happen anymore.</p> <p>Thanks,</p> <p>Malcolm</p> <p>PS: Please let me know if I need to provide more information.</p>

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