Batch script to make hardlinks from a TwinCAT plc project to a Unit test project.

hardlinkPousToTestProject.bat

@echo off

title Make hard links from project to test project

echo This script will make hard links of the project files in the POUs folder to the test project folder.
echo Before running this script make sure you already created the neccesarry folder structure in your Plc or TwinCAT project.

for %%i in (.\path\to\project\POUs\*.TcPOU) do (
	mklink /H .\path\to\testproject\POUs\%%~nxi %%i
)
pause

How to

Say you have a TwinCAT project called MyProject which you want to test with the TcUnit library. You create another project MyProject_Tests. So you have the following folder structure:

repos 
  ├── MyProject
  |  ├── MyProject
  |  |  ├── Plc
  |  |  |  ├── POUs
  |  |  |  └── Plc.plcproj
  |  |  └── MyProject.tsproj
  |  └── MyProject.sln
  |
  ├── MyProject_Tests
  |  ├── MyProject_Tests
  |  |  ├── Plc
  |  |  |  ├── POUs
  |  |  |  └── Plc.plcproj
  |  |  └── MyProject_Tests.tsproj
  |  └── MyProject_Tests.sln
  |
  └── hardlinkPousToTestProject.bat  

You then:

1. Add a folder Tests under Plc in the MyProject_Tests project.
2. Add a method you want to test to MyProject/MyProject/Plc/POUs.
3. Edit the path names in hardlinkPousToTestProject.bat such that they point to the correct folders. So for the current example:
   • for %%i in (.\path\to\project\POUs\*.TcPOU) do ( becomes for %%i in (.\MyProject\MyProject\Plc\POUs\*.TcPOU) do (
   • and mklink /H .\path\to\testproject\POUs\%%~nxi %%i becomes mklink /H .\MyProject_Tests\MyProject_Tests\Plc\POUs\%%~nxi %%i
4. Run the batch script.
5. Manually add the .TcPOU files to MyProject_Tests\MyProject_Tests\Plc\POUs
6. Add the MyProject_Tests\MyProject_Tests\Plc\POUs to .gitignore since this file is already in MyProject.

Your file structure should now look like this:

repos 
  ├── MyProject
  |  ├── MyProject
  |  |  ├── Plc
  |  |  |  ├── POUs
  |  |  |  |  └── Function.TcPOU  # Original file
  |  |  |  └── Plc.plcproj
  |  |  └── MyProject.tsproj
  |  └── MyProject.sln
  |
  ├── MyProject_Tests
  |  ├── MyProject_Tests
  |  |  ├── Plc
  |  |  |  ├── POUs
  |  |  |  |  └── Function.TcPOU   # Hard linked file
  |  |  |  ├── Tests
  |  |  |  |  └── Function_Tests.TcPOU  
  |  |  |  └── Plc.plcproj
  |  |  └── MyProject_Tests.tsproj
  |  └── MyProject_Tests.sln
  |
  └── hardlinkPousToTestProject.bat  

Now you can change Function.TcPOU from either MyProject or MyProject_Tests!

Hello,
Thank you for this batch file.

Is this line needs correction?
Manually add the .TcPOU files to the _MyProject\_Tests_ project

Like this?
Manually add the .TcPOU files to the _MyProject_Tests\Plc\POUs

Thanks @kumaraswamygaviyappa! Nice catch.

If the batch file is executed for the second time, Error is generated: A file cannot be created if it already exists.

Yes that is correct. You only have to link a file once.