Share values that are created upon running a suite of pramatized unit tests in parallel

Hello,

I need help with sharing values that are created upon running a suite of pramatized unit tests in parallel.

I'm guessing this can be achieved with parallel plugins or shared fixtures but I'm not sure on how to use either of them.

Below is an example taken from Create Basic Parameterized Test - MATLAB & Simulink - MathWorks United Kingdom and edited to try and show what I am trying to achieve, showing the diffference of running sequentially and in parallel.

Any help would be greatly appreciated.

Regards

Imraan

runtests("TestCarpet")
delete(TestCarpet.FileName)

Name Passed Failed Incomplete Duration Details

__________________________________________________ ______ ______ __________ _________ ____________

{'TestCarpet/testNumel(level=small,side=small)' } true false false 0.015111 {1×1 struct}

{'TestCarpet/testNumel(level=medium,side=medium)'} true false false 0.0058167 {1×1 struct}

{'TestCarpet/testNumel(level=large,side=large)' } true false false 0.0078009 {1×1 struct}

runtests("TestCarpet","UseParallel",true)
delete(TestCarpet.FileName)

Name Passed Failed Incomplete Duration Details

__________________________________________________ ______ ______ __________ ________ ____________

{'TestCarpet/testNumel(level=small,side=small)' } true false false 0.085126 {1×1 struct}

{'TestCarpet/testNumel(level=medium,side=medium)'} false true false 0.68034 {1×1 struct}

{'TestCarpet/testNumel(level=large,side=large)' } false true false 0.67238 {1×1 struct}

Example taken from Create Basic Parameterized Test - MATLAB & Simulink - MathWorks United Kingdom and edited to implement my example.

classdef TestCarpet < matlab.unittest.TestCase   
    
    properties(Constant)
        FileName = "somedata.txt";
    end

    properties
        % Values I want to share in parallel
        Date (1,:) datetime
        UUID (1,:) string
    end

    properties (TestParameter)
        type  = {'single','double','uint16'};
        level = struct('small',2,'medium',4,'large',6);
        side  = struct('small',9,'medium',81,'large',729);
    end

    methods(TestClassSetup)

        function init(this)
            % Values I want to share in parallel.
            this.Date = datetime('now');
            this.UUID = matlab.lang.internal.uuid;

            if ~isfile(this.FileName)
                lines = [string(this.Date); this.UUID];
                writelines(lines, this.FileName);
            end            
        end

    end
    
    methods (Test, ParameterCombination = 'sequential')
        function testNumel(testCase,level,side)
            import matlab.unittest.constraints.HasElementCount

            % ----- I want the date and UUID common for all Parameterized tests when running in parallel             
            
            expectedData = readlines(testCase.FileName, 'EmptyLineRule','skip');
            actualData   = [string(testCase.Date); testCase.UUID];

            arrayfun(@(x,y) testCase.verifyMatches(x, y), actualData, expectedData)
            %---------------------------------------------------------


            % Code from Matlab Documentation that I don't care about
            % testCase.verifyThat(sierpinski(level), HasElementCount(side^2))
        end
    end     
end

[Alvaro]

Could you elaborate a bit more on your workflow? It's not clear to me what you mean by wanting to share values in parallel. Are you trying to initialize a parallel pool of workers and have each worker have access to those values?

If you use runInParallel, then your TestClassSetup method will run locally on each worker.

https://www.mathworks.com/help/matlab/ref/matlab.unittest.testrunner.runinparallel.html

[Imraan Ibrahim]

Hi,

Yes, I am trying to initialize a parallel pool of workers and have each worker have access to the same timestamp and uuid.

This works when I'm NOT running in parallel as the TestClassSetup runs once for all the parmatized unit tests.

As you mentioned, the TestClassSetup method will run locally on each worker, which means that each call of TestClassSetup will give slightly different timestamps the workers don't start at the exact same time and also the uuids will be different.

Constant properties won't work for me as I need a new Timestamp and uuid each time I run a test suite.

[Alvaro]

Would parameterization properties work for you? For example:

classdef myTestClass < matlab.unittest.TestCase
    
    properties(Constant)
        FileName = "somedata.txt";
    end
    properties(TestParameter)
        myParam = {datetime('now')};
        anotherParam = {matlab.lang.internal.uuid};
    end
    methods(Test)
        function myTest1(testcase, myParam, anotherParam)
            writelines(string(myParam), testcase.FileName, WriteMode = "append");
            writelines(string(anotherParam), testcase.FileName, WriteMode = "append");
        end
        function myTest2(testcase, myParam, anotherParam)
            writelines(string(myParam), testcase.FileName, WriteMode = "append");
            writelines(string(anotherParam), testcase.FileName, WriteMode = "append");
        end
        
        function myTest3(testcase, myParam, anotherParam)
            writelines(string(myParam), testcase.FileName, WriteMode = "append");
            writelines(string(anotherParam), testcase.FileName, WriteMode = "append");
        end
    end
end

Try runtests("myTestClass",'UseParallel',true) and you will see in somedata.txt that all workers have access to same timestamp and UUID.