matlab.mock.actions.ThrowException class

Package: matlab.mock.actions

Throw exception when method is called or when property is set or accessed


To specify that the framework throws an exception when a mock object method is invoked or when a mock object property is set or accessed, use the ThrowException class. You can use this action to inject error conditions into the system under test.


action = ThrowException throws an exception when a method is called or a property is set or accessed.

action = ThrowException(exception) specifies the exception that the mock throws.

Input Arguments

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Exception for the framework to throw at method call or property interaction, specified as a scalar MException object.

Example: MException('MyProduct:myID','My exception message.')


repeatRepeat same action multiple times
thenSpecify action

Copy Semantics

Value. To learn how value classes affect copy operations, see Copying Objects.


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Create a mock for a bank account class.

testCase = matlab.mock.TestCase.forInteractiveUse;
[mock,behavior] = testCase.createMock('AddedMethods',"deposit");

Set up behavior.

import matlab.mock.actions.ThrowException;
import matlab.unittest.constraints.IsLessThan;
when(behavior.deposit(IsLessThan(0)), ...
    ThrowException(MException('Account:deposit:Negative', ...
    'Deposit amount must be positive.')));

Use the mock.

Error using matlab.mock.internal.MockContext>mockMethodCallback (line 663)
Deposit amount must be positive.

Error in matlab.mock.internal.MockContext>@(data)mockMethodCallback(data,catalog) (line 282)
            methodCallback = @(data)mockMethodCallback(data, catalog);


For simple definition of outputs, you can use the throwExceptionWhen method of the matlab.mock.TestCase class. However, there is more functionality when you use the ThrowException action.

Introduced in R2017a