R: Create a Result Descriptor by Recording Effects of an...

In realtest: Where Expectations Meet Reality: Realistic Unit Testing

Create a Result Descriptor by Recording Effects of an Expression Evaluation

Description

Evaluates an expression and records its direct and indirect effects: the resulting value as well as the information whether any errors, warnings, or messages are generated and if anything is printed on stdout or stderr.

Usage

R(expr, ..., envir = parent.frame())

Arguments

expr	expression to be evaluated
...	further arguments to be passed to P
envir	environment where expr is to be evaluated

Details

Note that messages, warnings, and errors are typically written to stderr, but these are considered separately here. In other words, when testing expectations with E, e.g., the reference stderr should not include the anticipated diagnostic messages.

There may be other side effects, such as changing the state of the random number generator, modifying options or environment variables, modifying the calling or global environment (e.g., creating new global variables), attaching objects onto the search part (e.g., loading package namespaces), or plotting, but these will not be captured, at least, not by the current version of the realtest package.

Value

A list of class realtest_descriptor, see P, which this function calls. The additional named component expr gives the expression that generated the value. Moreover, args gives a named list of objects that appeared in expr (not including functions called).

If an effect of particular kind does not occur, it is not included in the resulting list. stdout, stderr, and error are at most single strings.

When an error occurs, value is NULL.

Author(s)

Marek Gagolewski

See Also

The official online manual of realtest at https://realtest.gagolewski.com/

Related functions: E, P

Examples

y <- 1:10; R(sum(y^2))
R(cat("a bit talkative, innit?"))
R(sqrt(c(-1, 0, 1, 2, 4)))
R(log("aaaargh"))
R({
    cat("STDOUT"); cat("STDERR", file=stderr()); message("MESSAGE");
    warning("WARNING"); warning("WARNING AGAIN"); cat("MORE STDOUT");
    message("ANOTHER MESSAGE"); stop("ERROR"); y; "NO RETURN VALUE"
})

realtest documentation built on May 31, 2023, 8:21 p.m.