robotframework-doctestlibrary 0.4.0

A library for Visual Document Testing

robotframework-doctestlibrary

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Robot Framework DocTest library. Simple Automated Visual Document Testing.

Powered by

• Open CV
• scikit-image
• ImageMagick (only needed for rendering .ps and .pcl files)
• Ghostscript (only needed for rendering .ps and .pcl files)
• PyWand (only needed for rendering .ps and .pcl files)
• Tesseract OCR
• parsimonious (only needed for parsing .pcl and .ps files for)
• pymupdf
• The knowledge of stackoverflow.com

See keyword documentation for

• Visual Document Tests
• Print Job Tests
• Pdf Tests (very basic)

See Talk from RoboCon2021 for a short demo and some background.

Installation instructions

Only Python 3.X or newer is supported. Tested with Python 3.8/3.9/3.10

In general, an installation via pip or setup.py is possible.

I recommend to use pip as it will also install a required binary libdmtx-64.dll (for windows) automatically.

Install robotframework-doctestlibrary

Installation via pip

• pip install --upgrade robotframework-doctestlibrary

Installation via setup.py

• Clone the robotframework-doctestlibrary
  git clone https://github.com/manykarim/robotframework-doctestlibrary.git
• Install via setup.py
  python setup.py install

Installation via poetry

• poetry install

Install dependencies

Install Tesseract, Ghostscript, GhostPCL, ImageMagick binaries
Hint: Since 0.2.0 Ghostscript, GhostPCL and ImageMagick are only needed for rendering .ps and .pclfiles.
Rendering and content parsing of .pdf is done via MuPDF
In the future there might be a separate pypi package for .pcl and .ps files to get rid of those dependencies.

• Linux
• apt-get install imagemagick
• apt-get install tesseract-ocr
• apt-get install ghostscript
• apt-get install libdmtx0b
• Windows
• https://github.com/UB-Mannheim/tesseract/wiki
• https://ghostscript.com/releases/gsdnld.html
• https://ghostscript.com/releases/gpcldnld.html
• https://imagemagick.org/script/download.php

Some special instructions for Windows

Rename executable for GhostPCL to pcl6.exe (only needed for .pcl support)

The executable for GhostPCL gpcl6win64.exe needs to be renamed to pcl6.exe

Otherwise it will not be possible to render .pcl files successfully for visual comparison.

Add tesseract, ghostscript and imagemagick to system path in windows (only needed for OCR, .pcl and .ps support)

• C:\Program Files\ImageMagick-7.0.10-Q16-HDRI
• C:\Program Files\Tesseract-OCR
• C:\Program Files\gs\gs9.53.1\bin
• C:\Program Files\gs\ghostpcl-9.53.1-win64

(The folder names and versions on your system might be different)

That means: When you open the CMD shell you can run the commands

• magick.exe
• tesseract.exe
• gswin64.exe
• pcl6.exe

successfully from any folder/location

Windows error message regarding pylibdmtx

How to solve ImportError for pylibdmtx

If you see an ugly ImportError when importing pylibdmtx on Windows you will most likely need the Visual C++ Redistributable Packages for Visual Studio 2013. Install vcredist_x64.exe if using 64-bit Python, vcredist_x86.exe if using 32-bit Python.

ImageMagick

The library might return the error File could not be converted by ImageMagick to OpenCV Image: <path to the file> when comparing PDF files. This is due to ImageMagick permissions. Verify this as follows with the sample.pdf in the testdata directory:

convert sample.pdf sample.jpg 
convert-im6.q16: attempt to perform an operation not allowed by the security policy

Solution is to copy the policy.xml from the repository to the ImageMagick installation directory.

Docker

You can also use the docker images or create your own Docker Image docker build -t robotframework-doctest . Afterwards you can, e.g., start the container and run the povided examples like this:

• Windows
  • docker run -t -v "%cd%":/opt/test -w /opt/test robotframework-doctest robot atest/Compare.robot
• Linux
  • docker run -t -v $PWD:/opt/test -w /opt/test robotframework-doctest robot atest/Compare.robot

Gitpod.io

Try out the library using Gitpod

Updates

Now built with poetry

With version 0.3.0 the library is now built with poetry. Some refactoring and small cleanup were done, without changing the functionality.

Hello PyMuPDF

With version 0.2.0 the PDF Rendering and PDF content reading is done via PyMuPDF (instead of Ghostscript and ImageMagick/PyWand).
Due to that change PyMuPDF was added to the dependencies and needs to be installed (e.g. via pip)
For the time being, Ghostscript and ImageMagick/PyWand will be kept as dependencies, as they are needed for rendering .pcland .ps files.
But both might be removed in the future which will simplify the installation.

##PDF Content Checks Thanks to PyMuPDF it was possible to implement more content checks for .PDF files.

• Text Content
• Digital Signatures
• Metadata
• Images
• Used Fonts

Each content type can also be compared separately.
Have a look at PDF Content Tests

Examples

Check the /atest/Compare.robot test suite for some examples.

Testing with Robot Framework

*** Settings ***
Library    DocTest.VisualTest

*** Test Cases ***
Compare two Images and highlight differences
    Compare Images    Reference.jpg    Candidate.jpg

Use masks/placeholders to exclude parts from visual comparison

*** Settings ***
Library    DocTest.VisualTest

*** Test Cases ***
Compare two Images and ignore parts by using masks
    Compare Images    Reference.jpg    Candidate.jpg    placeholder_file=masks.json

Compare two PDF Docments and ignore parts by using masks
    Compare Images    Reference.jpg    Candidate.jpg    placeholder_file=masks.json

Compare two Farm images with date pattern
    Compare Images    Reference.jpg    Candidate.jpg    placeholder_file=testdata/pattern_mask.json

Compare two Farm images with area mask as list
    ${top_mask}    Create Dictionary    page=1    type=area    location=top    percent=10
    ${bottom_mask}    Create Dictionary    page=all    type=area    location=bottom    percent=10
    ${masks}    Create List    ${top_mask}    ${bottom_mask}
    Compare Images    Reference.jpg    Candidate.jpg    mask=${masks}

Compare two Farm images with area mask as string
    Compare Images    Reference.jpg    Candidate.jpg    mask=top:10;bottom:10

Different Mask Types to Ignore Parts When Comparing

Areas, Coordinates, Text Patterns

[
    {
    "page": "all",
    "name": "Date Pattern",
    "type": "pattern",
    "pattern": ".*[0-9]{2}-[a-zA-Z]{3}-[0-9]{4}.*"
    },
    {
    "page": "1",
    "name": "Top Border",
    "type": "area",
    "location": "top",
    "percent":  5
    },
    {
    "page": "1",
    "name": "Left Border",
    "type": "area",
    "location": "left",
    "percent":  5
    },
    {
    "page": 1,
    "name": "Top Rectangle",
    "type": "coordinates",
    "x": 0,
    "y": 0,
    "height": 10,
    "width": 210,
    "unit": "mm"
    }
]

Accept visual different by checking move distance or text content

*** Settings ***
Library    DocTest.VisualTest

*** Test Cases ***
Accept if parts are moved up to 20 pixels by pure visual check
    Compare Images    Reference.jpg    Candidate.jpg    move_tolerance=20

Accept if parts are moved up to 20 pixels by reading PDF Data
    Compare Images    Reference.pdf    Candidate.pdf    move_tolerance=20    get_pdf_content=${true}

Accept differences if text content is the same via OCR
    Compare Images    Reference.jpg    Candidate.jpg    check_text_content=${true}

Accept differences if text content is the same from PDF Data
    Compare Images    Reference.pdf    Candidate.pdf    check_text_content=${true}    get_pdf_content=${true}

Options for taking additional screenshots, screenshot format and render resolution

Take additional screenshots or reference and candidate file.

*** Settings ***
Library    DocTest.VisualTest   take_screenshots=${true}    screenshot_format=png

Take diff screenshots to highlight differences

*** Settings ***
Library    DocTest.VisualTest   show_diff=${true}    DPI=300

Experimental usage of Open CV East Text Detection to improve OCR

*** Settings ***
Library    DocTest.VisualTest

*** Test Cases ***
Compare two Farm images with date pattern and east detection
    Compare Images    Reference.jpg    Candidate.jpg    placeholder_file=masks.json    ocr_engine=east

Check content of PDF files

*** Settings ***
Library    DocTest.PdfTest

*** Test Cases ***
Check if list of strings exists in PDF File
    @{strings}=    Create List    First String    Second String
    PDF Should Contain Strings    ${strings}    Candidate.pdf
    
Compare two PDF Files and only check text content
    Compare Pdf Documents    Reference.pdf    Candidate.pdf    compare=text

Compare two  PDF Files and only check text content and metadata
    Compare Pdf Documents    Reference.pdf    Candidate.pdf    compare=text,metadata
    
Compare two  PDF Files and check all possible content
    Compare Pdf Documents    Reference.pdf    Candidate.pdf

Ignore Watermarks for Visual Comparisons

Store the watermark in a separate B/W image or PDF.
Watermark area needs to be filled with black color.
Watermark content will be subtracted from Visual Comparison result.

*** Settings ***
Library    DocTest.VisualTest

*** Test Cases ***
Compare two Images and ignore jpg watermark
    Compare Images    Reference.jpg    Candidate.jpg    watermark_file=Watermark.jpg

Compare two Images and ignore pdf watermark
    Compare Images    Reference.pdf    Candidate.pdf    watermark_file=Watermark.pdf

Compare two Images and ignore watermark folder
    Compare Images    Reference.pdf    Candidate.pdf    watermark_file=${CURDIR}${/}watermarks

Watermarks can also be passed on Library import. This setting will apply to all Test Cases in Test Suite

*** Settings ***
Library    DocTest.VisualTest   watermark_file=${CURDIR}${/}watermarks

*** Test Cases ***
Compare two Images and ignore watermarks
    Compare Images    Reference.jpg    Candidate.jpg

Get Text From Documents or Images

*** Settings ***
Library    DocTest.VisualTest

*** Test Cases ***
Get Text Content And Compare
    ${text}    Get Text From Document    Reference.pdf
    List Should Contain Value    ${text}    Test String

Using pabot to run tests in parallel

Document Testing can be run in parallel using pabot.
However, you need to pass the additional arguments --artifacts and --artifactsinsubfolders to the pabot command, to move the screenshots to the correct subfolder.
Otherwise the screenshots will not be visible in the log.html

pabot --testlevelsplit --processes 8 --artifacts png,jpg,pdf,xml --artifactsinsubfolders /path/to/your/tests/

Visual Testing of Web Applications

I experimented a bit and tried to use this library for Visual Testing of Web Applications.
Please have a look at this pilot example here

Development

Feel free to create issues or pull requests.
I'm always happy for any feedback.

Core team

In order of appearance.

• Many Kasiriha

Contributors

This project is community driven and becomes a reality only through the work of all the people who contribute.