assert_checkerror

Check that a command raises the expected error.

📝 Syntax

• assert_checkerror(command, expected_error_message)

• r = assert_checkerror(command, expected_error_message)

• [r, msg] = assert_checkerror(command, expected_error_message)

• assert_checkerror(command, expected_error_message, expected_error_identifier)

• r = assert_checkerror(command, expected_error_message, expected_error_identifier)

• [r, msg] = assert_checkerror(command, expected_error_message, expected_error_identifier)

📥 Input argument

• command - a string containing the command to execute and test for errors.

• expected_error_message - a string containing the expected error message that should be raised.

• expected_error_identifier - a string containing the expected error identifier (optional).

📤 Output argument

• r - a logical value: true if the test passes, false otherwise.

• msg - a string containing the error message. If r == true, then msg == ''. If r == false, then msg contains the assertion failure message.

📄 Description

assert_checkerror verifies that executing a command raises the expected error message.

If the command does not raise any error, or if it raises an error with a different message than expected, the assertion fails.

When the optional expected_error_identifier parameter is provided, the function also checks that the error identifier matches the expected one.

This function is particularly useful for unit testing to ensure that invalid inputs or operations properly generate the expected error conditions.

💡 Examples

Test that cos function with no arguments raises the expected error:

assert_checkerror('cos', _('Wrong number of input arguments.'));

Example that demonstrates assertion failure with wrong expected message:

try
    assert_checkerror('cos', _('Wrong error message.'));
catch ME
    disp(['Error: ' ME.message])
end

Test with both error message and error identifier:

assert_checkerror('mustBeFinite(NaN)', _('Value must be finite.'), 'Nelson:validators:mustBeFinite')

Using return values to handle assertion results:

[r, msg] = assert_checkerror('cos', _('Wrong number of input arguments.'));
if r
    disp('Test passed: cos function properly raises expected error')
else
    disp(['Test failed: ' msg])
end

🔗 See also

assert_istrue, assert_isfalse.

🕔 History

Version	📄 Description
1.0.0	initial version