Strange error when running pester with a function that calls Start-Process

[glennsarti]

I am trying to write unit tests for a function which eventually calls Start-Process. I've written a series of Pester tests that work fine in Powershell 4.0 and 3.0 but in 2.0 I get some strange behaviour.

Setup;
Windows 8.1 64bit - PS 4.0, .Net 4.5.1
Pester 3.3.8

Function under test - This function is in a module;

...
$result = (Start-Process -FilePath $JavaCMD.java `
    -ArgumentList $ShellArgs -Wait:$Wait -NoNewWindow:$Wait -PassThru)
...

I am not even Mocking the the Start-Process function but I received the error;

The variable cannot be validated because the value is not a valid value for the ArgumentList variable.

Note the double space in between 'value' and 's'. It's like Pester is mucking up the value being passed but I don't see how. All Mocks are within the context scope

Things I've tried but made no difference;

• Mocking Start-Process
• Removing the -ArgumentList from the function call (This is REALLY weird that it still gives an error!)
• Putting in a bad parameter in the function gave a different validation message i.e. Using -ArgumentList @() gave the following error message;
  [-] Error occurred in Context block 118ms Cannot validate argument on parameter 'ArgumentList'. The argument is null, empty, or an element of the argument collection contains a null value. Supply a collection that does not contain any null values and then try the command again. This error is expected

For the moment I'm just going to avoid those tests on PS 2.0 but any help with this issue would be great.

[nohwnd]

Thanks for reporting the issue. Could you please share code+test example that does not work for you? That way we can run it on our systems and determine what is wrong, without much guessing.

Btw I don't see any double spaces there. The markdown probably stripped them for you.

[glennsarti]

Source Files;
https://github.com/glennsarti/spike-Neo4J-Windows-Experiments/tree/master/posh-neo-cm/src/Neo4j-Management

Test Files;
https://github.com/glennsarti/spike-Neo4J-Windows-Experiments/tree/master/posh-neo-cm/tests/unit

The script under test is Start-Neo4jShell

The current test file has a Powershell Version IF around it. You'll need to remove that if for the error to occur.