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verifyInstanceOf

Class: matlab.unittest.qualifications.Verifiable
Package: matlab.unittest.qualifications

Verify value is object of specified type

Syntax

verifyInstanceOf(verifiable,actual,className)
verifyInstanceOf(verifiable,actual,metaClass)
verifyInstanceOf(___,diagnostic)

Description

verifyInstanceOf(verifiable,actual,className) verifies that actual is a MATLAB® value whose class is the class specified by className.

verifyInstanceOf(verifiable,actual,metaClass) verifies that actual is a MATLAB value whose class is the class specified by the meta.class instance metaClass.

verifyInstanceOf(___,diagnostic) also associates the diagnostic information in diagnostic with the qualification. Depending on the test runner configuration, the testing framework might display diagnostics when the qualification passes or fails. By default, the framework displays diagnostics only when the qualification fails. You can override the default behavior by customizing the test runner. For example, use a DiagnosticsOutputPlugin instance to display both failing and passing event diagnostics.

Input Arguments

verifiable

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

actual

The value to test.

className

Name of class, specified as a character vector.

metaClass

An instance of meta.class.

diagnostic

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.

Examples

expand all

These interactive tests verify the class of the number, 5.

Create a TestCase object and the value to test.

testCase = matlab.unittest.TestCase.forInteractiveUse;
actvalue = 5;

Verify actvalue is an instance of class double.

verifyInstanceOf(testCase, actvalue, 'double');
Interactive verification passed.

Verify if actvalue is an instance of char.

verifyInstanceOf(testCase, 5, 'char');
Interactive verification failed.

---------------------
Framework Diagnostic:
---------------------
verifyInstanceOf failed.
--> The value must be an instance of the expected type.
    
    Actual Class:
        double
    Expected Type:
        char

Actual Value:
         5

Test failed.

These tests verify function handles, specified as a meta.class instance, ?function_handle.

Create a function handle.

fh = @sin;
testCase = matlab.unittest.TestCase.forInteractiveUse;
verifyInstanceOf(testCase, fh, ?function_handle);
Interactive verification passed.

Test the function name.

fh = 'sin';
verifyInstanceOf(testCase, fh, ?function_handle);
Interactive verification failed.

---------------------
Framework Diagnostic:
---------------------
verifyInstanceOf failed.
--> The value must be an instance of the expected type.
    
    Actual Class:
        char
    Expected Type:
        function_handle

Actual Value:
    sin

Test failed.

Verify that a derived class is not the same class as its base class.

Create a class, BaseExample.

classdef BaseExample
end

Create a derived class, DerivedExample.

classdef DerivedExample < BaseExample
end

Verify DerivedExample is an instance of BaseExample.

testCase = matlab.unittest.TestCase.forInteractiveUse;
testCase.verifyInstanceOf(DerivedExample(), ?BaseExample);
Interactive verification passed.

Verify BaseExample is not an instance of DerivedExample.

testCase.verifyInstanceOf(BaseExample(), ?DerivedExample);
Interactive verification failed.

---------------------
Framework Diagnostic:
---------------------
verifyInstanceOf failed.
--> The value must be an instance of the expected type.
    
    Actual Class:
        BaseExample
    Expected Type:
        DerivedExample

Actual Value:
      BaseExample with no properties.

Test failed.

Tips

  • This method is functionally equivalent to:

    import matlab.unittest.constraints.IsInstanceOf;
    verifiable.verifyThat(actual, IsInstanceOf(className));
    verifiable.verifyThat(actual, IsInstanceOf(metaClass));
    

    There exists more functionality when using the IsInstanceOf constraint directly via verifyThat.

  • 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. Alternatively,

    • 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.

    • 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 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. For more information, see matlab.unittest.qualifications.FatalAssertable.

Introduced in R2013a