Class: matlab.unittest.qualifications.FatalAssertable
Package: matlab.unittest.qualifications

Fatally assert value meets specified constraint




fatalAssertThat(fatalAssertable,actual,constraint) fatally asserts that actual is a value that satisfies the constraint provided.

If the constraint is not satisfied, a fatal assertion failure is produced utilizing only the framework diagnostic generated by the constraint.

fatalAssertThat(fatalAssertable,actual,constraint,diagnostic) also displays the diagnostic information in diagnostic upon a failure.

When using this signature, both the diagnostic information contained within diagnostic is used in addition to the diagnostic information provided by the constraint.

Input Arguments


The matlab.unittest.TestCase instance which is used to pass or fail the fatal assertion in conjunction with the test running framework.


The value to test.


Constraint that the actual value must satisfy to pass the verification, specified as a matlab.unittest.constraints instance.


Diagnostic information related to the qualification, specified as one of the following:

  • string array

  • character array

  • function handle

  • matlab.unittest.diagnostics.Diagnostic object

Diagnostic values can be nonscalar. For more information, see matlab.unittest.diagnostics.Diagnostic.


See examples for verifyThat, and replace calls to verifyThat with fatalAssertThat.


  • Use fatal assertion qualifications to abort the test session upon failure. These qualifications are useful when the failure mode is so fundamental that there is no point in continuing testing. These qualifications are also useful when fixture teardown does not restore the MATLAB® state correctly and it is preferable to abort testing and start a fresh session. Alternatively,

    • Use assertion qualifications when the failure condition invalidates the remainder of the current test content, but does not prevent proper execution of subsequent test methods. A failure at the assertion point renders the current test method as failed and incomplete. For more information, see matlab.unittest.qualifications.Assertable.

    • Use verification qualifications to produce and record failures without throwing an exception. Since verifications do not throw exceptions, all test content runs to completion even when verification failures occur. Typically verifications are the primary qualification for a unit test since they typically do not require an early exit from the test. Use other qualification types to test for violation of preconditions or incorrect test setup. For more information, see matlab.unittest.qualifications.Verifiable.

    • Use assumption qualifications to ensure that the test environment meets preconditions that otherwise do not result in a test failure. Assumption failures result in filtered tests, and the testing framework marks the tests as Incomplete. For more information, see matlab.unittest.qualifications.Assumable.

Introduced in R2013a