matlab.unittest.qualifications.Assumable class

Package: matlab.unittest.qualifications

Qualification to filter test content

Description

The Assumable class provides a qualification to filter test content. Apart from actions performed in the event of failures, the Assumable class works the same as other matlab.unittest qualifications.

Upon an assumption failure, the Assumable class informs the testing framework of the failure by throwing an AssumptionFailedException. The test framework then marks the test content as filtered and continues testing. Often, assumptions are used to ensure that the test is run only when certain preconditions are met. However, running the test without satisfying the preconditions does not produce a test failure. Ensure that the test content is Exception Safe. If the failure condition is meant to produce a test failure, use assertions or verifications instead of assumptions.

The attributes specified in the TestCase method definition determine which tests are filtered. The following behavior occurs when the test framework encounters an assumption failure inside of a TestCase method:

If you define the TestCase method using the Test attribute, the framework marks the entire method as filtered and runs subsequent test methods.
If you define the TestCase method using the TestMethodSetup or TestMethodTeardown attributes, the test framework marks the method to run for that instance as filtered.
If you define the TestCase method using the TestClassSetup or TestClassTeardown attributes, the test framework filters the entire TestCase class.

Filtering test content using assumptions does not produce test failures. Therefore, dead test code can result. Avoid this by monitoring filtered tests.

Methods

assumeClass	Assume exact class of specified value
assumeEmpty	Assume value is empty
assumeEqual	Assume value is equal to specified value
assumeError	Assume function throws specified exception
assumeFail	Produce unconditional assumption failure
assumeFalse	Assume value is false
assumeGreaterThan	Assume value is greater than specified value
assumeGreaterThanOrEqual	Assume value is greater than or equal to specified value
assumeInstanceOf	Assume value is object of specified type
assumeLength	Assume value has specified length
assumeLessThan	Assume value is less than specified value
assumeLessThanOrEqual	Assume value is less than or equal to specified value
assumeMatches	Assume string matches specified regular expression
assumeNotEmpty	Assume value is not empty
assumeNotEqual	Assume value is not equal to specified value
assumeNotSameHandle	Assume value is not handle to specified instance
assumeNumElements	Assume value has specified element count
assumeReturnsTrue	Assume function returns true when evaluated
assumeSameHandle	Assume two values are handles to same instance
assumeSize	Assume value has specified size
assumeSubstring	Assume string contains specified string
assumeThat	Assume value meets specified constraint
assumeTrue	Assume value is true
assumeWarning	Assume function issues specified warnings
assumeWarningFree	Assume function issues no warnings

Events

`AssumptionFailed`	Triggered upon failing assumption. A `QualificationEventData` object is passed to listener callback functions.
`AssumptionPassed`	Triggered upon passing assumption. A `QualificationEventData` object is passed to listener callback functions.

Copy Semantics

Handle. To learn how handle classes affect copy operations, see Copying Objects.

Examples

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Write TestClassSetup Method Using Assumptions

Assumptions assure that a test runs only when certain preconditions are satisfied and when such an event should not produce a test failure. When an assumption failure occurs, the test is marked as filtered.

Create IsSupportedTest test case. Refer to the following IsSupportedTest test case in the subsequent steps in this example, which highlight specific functions in the file.

IsSupportedTest Class Definition File

To execute the MATLAB^® commands in this example, add the IsSupportedTest.m file to a folder on your MATLAB path.

Write Test to Verify Platform. All tests in this test case must run on UNIX^® platforms only. The TestPlatform function uses the assumeFalse method to test if MATLAB is running on a Windows^® platform. If it is, the test fails.

function TestPlatform(testcase)
    testcase.assumeFalse(ispc,...
        'Do not run any of these tests on Windows.')
end

Make TestPlatform a TestClassSetup Test. To make the TestPlatform test a precondition, add it inside the methods (TestClassSetup) block.

Run the test case. Create a test case object and run the tests on a Windows platform.

tc = IsSupportedTest;
res = tc.run;

Running IsSupportedTest

================================================================================
All tests in IsSupportedTest were filtered.
    Test Diagnostic: Do not run any of these tests on Windows.
    Details
================================================================================

Done IsSupportedTest
__________

Failure Summary:

     Name                   Failed  Incomplete  Reason(s)
    ====================================================================
     IsSupportedTest/test1              X       Filtered by assumption.

The test(s) were filtered, and did not run (marked Incomplete).

For more information, click the Details link.

================================================================================
An assumption was not met while setting up or tearing down IsSupportedTest.
As a result, all IsSupportedTest tests were filtered.

    ----------------
    Test Diagnostic:
    ----------------
    Do not run any of these tests on Windows.

    ---------------------
    Framework Diagnostic:
    ---------------------
    assumeFalse failed.
    --> The value must evaluate to "false".
    
    Actual Value:
             1

    ------------------
    Stack Information:
    ------------------
    In C:\work\IsSupportedTest.m (IsSupportedTest.TestPlatform) at 4
================================================================================

The link to IsSupportedTest.TestPlatform under Stack Information takes you to the failed assumeFalse method.

More About

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Exception Safe

Test content is exception safe when all fixture teardown is performed with addTeardown or through the appropriate object destructors when a failure occurs. This ensures that the failure does not affect later testing due to stale fixtures.

This code is not exception safe. After an assertion failure, the test framework does not close the figure.

% Not exception safe
f = figure;
testCase.assumeEqual(actual, expected)
close(f)

This code is exception safe because the test framework closes the figure in all cases.

% Exception safe
f = figure;
testCase.addTeardown(@close, f)
testCase.assumeEqual(actual, expected)

However, tearing down a fixture using addTeardown does not guarantee code is exception safe. This code shows a failure in assumeEqual.

% Not exception safe
f = figure;
testCase.assumeEqual(actual, expected)
testCase.addTeardown(@close, f)

Documentation

matlab.unittest.qualifications.Assumable class

Description

Methods

Events

Copy Semantics

Examples

Write TestClassSetup Method Using Assumptions

More About

Exception Safe

See Also

Topics

MATLAB Documentation

Support