Using both strings and functions in Matlab UnitTest diagnostics? - matlab

Question

Please refer to the documentation for the testCase.verifyEqual method here. The documentation says that only one of the diagnostic features can be used. My requirement is I need two diagnostics at the same time - strings and function handle. The following is simple example of what I'm trying to achieve,
classdef testArrays < matlab.unittest.TestCase
methods (Test)
function testArraysEquality(testCase)
a = 1:10;
b = 1:10;
incrementFunc = #(x)x+1;
failureCount;
for i=1:length(a)
testCase.verifyEqual(a(i),b(i),'AbsTol',10e-3,['Test failed array element# ' num2str(i) ' failure count ' num2str(incrementFunc(failureCount))]);
end
disp([num2str(failureCount) ' out of ' num2str(length(a)) ' test cases failed']);
end
end
end
The problem is Anonymous function don't store values. On the other hand with the 'assignin' feature shown below, the value can be incremented and stored, but cannot be returned for use inside disp(). Is there any work around for this?
incrementFunc1 = #(x) assignin('caller', inputname(1), x+1);

Answer 1

You can include more than one (as well as more than one type) of diagnostic in the MATLAB Unit Test Framework by simply providing a diagnostic array to verifyEqual. You can actually do this explicitly as follows:
import matlab.unittest.diagnostics.StringDiagnostic;
import matlab.unittest.diagnostics.FunctionHandleDiagnostic;
testCase.verifyEqual(a,e, [StringDiagnostic('some string'), FunctionHandleDiagnostic(#() someFunction)]);
However, the Diagnostic.join method is provided to make that easier:
import matlab.unittest.diagnostics.Diagnostic;
testCase.verifyEqual(a,e, Diagnostic.join('some string', #() someFunction));
In order to do the increment call you are probably going to want to add a failed listener to the testCase in order to increment properly. Note that people/plugins can actually add listeners and execute these diagnostics in passing cases in addition to failing cases. As such your diagnostic messages should not assume that every time they are invoked it is in a failure condition. This not only applies to your incrementing code but also to just the message you are providing. I would suggest that instead of saying:
Test failed array element# 3 failure count 2
you should say:
Tested array element# 3 failure count 2
The framework diagnostic will let you know whether it failed or not. Anyway, takeaway, don't rely on invoking the diagnostics to determine failure count. What then? Take a look at the Events section here. You should listen explicitly for verification failed events in order to add that information to your diagnostics.
For the first solution, I am not sure why you need to provide the failure count for every failure. It seems like that would be very verbose. If you don't need that then you can do something like this:
classdef testArrays < matlab.unittest.TestCase
methods (Test)
function testArraysEquality(testCase)
a = 1:10;
b = 1:10;
failureCount = 0;
testCase.addlistener('VerificationFailed', #incrementFailureCount);
function incrementFailureCount(varargin)
% This is a nested function & has the scope and can see/modify
% the failureCount variable. This could also be done with a
% property on the class ans a method that increments it
failureCount = failureCount + 1;
end
for i=1:length(a)
testCase.verifyEqual(a(i),b(i),'AbsTol',10e-3,['Tested array element # ' num2str(i)]);
end
% I suggest using log instead of disp. If you want it to show up most of the time you can
% log it at Terse (1) verbosity. However, if you don't want to see it you can turn it off.
testCase.log(1, sprintf('%d out of %d test cases failed', failureCount, length(a)));
end
end
end
Is that good enough? If you really want to show the failure count in the diagnostics for each failure you can its just a bit more complicated and requires another nested function (or property access).
classdef testArrays < matlab.unittest.TestCase
methods (Test)
function testArraysEquality(testCase)
import matlab.unittest.diagnostics.Diagnostic;
a = 1:10;
b = 1:10;
failureCount = 0;
testCase.addlistener('VerificationFailed', #incrementFailureCount);
function incrementFailureCount(varargin)
failureCount = failureCount + 1;
end
function displayFailureCount
fprintf(1, 'Failure Count: %d', failureCount);
end
for i=1:length(a)
testCase.verifyEqual(a(i),b(i),'AbsTol',10e-3, ...
Diagnostic.join(...
['Tested array element #' num2str(i)], ...
#displayFailureCount));
end
testCase.log(1, sprintf('%d out of %d test cases failed', failureCount, length(a)));
end
end
end
Does that help you accomplish what you are trying to do?