This function evalutes a test function at run time to decide whether to administer a series of test elements to the participant. If the test returns TRUE, then the test elements are shown, otherwise these test elements are skipped.

conditional(test, logic)

## Arguments

test Function to evaluate at run time. This function must accept the argument ..., and optionally the following named arguments: state, the participant's state object; input, the current page's Shiny input object; output, the current page's Shiny output object; session, the current Shiny session object; opt, the test's option list as created by test_options. Either a single test element, a list of test elements, or a timeline, which will be displayed conditionally on the basis of the outcome of test.

## Value

A list of test elements, or equivalently a timeline, which can be combined with other test elements or timelines.