Unit Testing : Figures

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Simon Parten
Simon Parten on 4 Apr 2019
Commented: Alex Kashuba on 7 Jun 2020
My use case. I have some digraph plots, I'd like to verify the values on certain edges, hold the right values. What I'm doing, is plotting one figure per test, by calling
h = digraph.plot
verifySubstring(testCase, h.EdgeLabel{1}, '1,000,000')
However, what I'd also like, is then when all the test have fun, to get an overview, of each.
Normally, I'd try something like this;
Where align figures comes from the matlab file exchange, and figs is a list of the figures created through each of the independant unit tests.
What I can't figure out... is how to persist the figure references, through the test cases...
Any ideas? I realise this sort of defies the point of independant unit tests... but it would be quite helpful, in this specific use case.
Alex Kashuba
Alex Kashuba on 7 Jun 2020
@Simon, this will never work. The reason is the mechnism of the TestRunner.
If you have 5 test in a test class, then TestRunner creates 7 instances of the Test class and in each instances runs only one test. This is done so in order that tests (that can run in random order would not interact)
Therefore all class properties are 'bare'.

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Accepted Answer

Andy Campbell
Andy Campbell on 4 Apr 2019
Edited: Andy Campbell on 4 Apr 2019
Does the approach outlined here work for your case?
  1 Comment
Simon Parten
Simon Parten on 5 Apr 2019
Edited: Simon Parten on 5 Apr 2019
For those interested, here is the skeleton of the solution I ended up with, based on Andy's documentation. For my use case, this is fantastic. Test class sketch
function createFigure(testCase)
figure('Renderer', 'painters', 'Position', [50 50 1800 900]);
function sortFigure(testCase)
set(gcf, 'Name', testCase.testName);
testCase.addTeardown(@(testCase) testCase.log(3, ...
matlab.unittest.diagnostics.Diagnostic.join(testCase.testName, ...
matlab.unittest.diagnostics.FigureDiagnostic(gcf))), testCase);
function test_SingleLossNATC_Ins(testCase)
h = aModel.plotMean;
verifySubstring(testCase, h.EdgeLabel{1}, '1,000,000');
testCase.testName = "NA TC Single loss of 51m";
And then the 'runner' setup ...
import matlab.unittest.plugins.TestReportPlugin;
runner = matlab.unittest.TestRunner.withTextOutput;
mypath = strcat(pwd, '\structureReport');
runner.ArtifactsRootFolder = mypath;
runner.addPlugin(TestReportPlugin.producingHTML(mypath, 'Verbosity',3));

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More Answers (1)

Steven Lord
Steven Lord on 4 Apr 2019
I believe the unit testing infrastructure tries not to let you do that sort of thing, as it means that you don't really have a four phase test. You're performing Setup, Exercise, and Verify but skipping Teardown. That could lead the software under test to be in a different state than it should be at the start of the next test, and could allow information to "leak" from one test method to another as you already mentioned.
If you were doing this to capture the figure when the Verify phase of your test method fails (to aid in debugging) you could use a FigureDiagnostic. If you wanted to capture all the figures in case any failure occurs then delete the saved figures if all the test methods passed, you could use a TemporaryFolderFixture with 'PreservingOnFailure' set to true then save the figures as .fig files in that temporary folder during each test method. If any failure occurs, the temporary folder will be spared; otherwise it and its contents will be deleted when the test finishes execution.
There are a couple other potential approaches I can think of, but before I mention them I'd like to know a little more about how you're planning to use all those figures.
  1 Comment
Simon Parten
Simon Parten on 4 Apr 2019
I think this is the answer I'm looking for - basically in this case, it appears I want to violate one of the principles of unit testing... Probably, that means I'm trying to do the wrong thing!
Basically, I wanted a quick visual (non persistent) summary (otherwise I have to clear it all up!) of each test at the end of the run. I think I can live without this for the time being.

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