R: RUnit check functions

checkFuncs {RUnit} | R Documentation

## RUnit check functions

### Description

A set of functions used to check the results of some test calculation. If these functions are called within the RUnit framework, the results of the checks are stored and reported in the test protocol.

`checkEquals` compares two R objects by invoking `all.equal` on the two objects. If the objects are not equal an error is generated and the failure is reported to the test logger such that it appears in the test protocol.

`checkEqualsNumeric` works just like `checkEquals` except that it invokes `all.equal.numeric` instead of `all.equal`

`checkIdentical` is a convenience wrapper around identical using the error logging mechanism of RUnit.

`checkTrue` uses the function `identical` to check if the expression provided as first argument evaluates to `TRUE`. If not, an error is generated and the failure is reported to the test logger such that it appears in the test protocol.

`checkException` evaluates the passed expression and uses the `try` mechanism to check if the evaluation generates an error. If it does the test is OK. Otherwise an error is generated and the failure is reported to the test logger such that it appears in the test protocol.

`DEACTIVATED` interrupts the test function and reports the test case as deactivated. In the test protocol deactivated test functions are listed separately. Test case deactivation can be useful in the case of major refactoring. Alternatively, test cases can be commented out completely but then it is easy to forget the test case altogether.

### Usage

    checkEquals(target, current, msg,
                tolerance = .Machine$double.eps^0.5,
                checkNames = TRUE, ...)
    checkEqualsNumeric(target, current, msg,
                       tolerance = .Machine$double.eps^0.5, ...)
    checkIdentical(target, current, msg)
    checkTrue(expr, msg)
    checkException(expr, msg, silent = getOption("RUnit")$silent)
    DEACTIVATED(msg)

### Arguments

`current, target` | objects to be compared (`checkEqualsNumeric` cannot handle S4 class objects).
`msg` | an optional message to document a check and to facilitate the identification of a possible failure. The message only appears as text in the test protocol, it is not further used in any of the check functions.
`tolerance` | numeric >= 0. A numeric check does not fail if differences are smaller than ‘tolerance’.
`checkNames` | flag, if `FALSE` the names attributes are set to `NULL` for both current and target before performing the check.
`expr` | syntactically valid R expression which can be evaluated and must return a logical scalar (`TRUE`|`FALSE`). A named expression is also allowed but the name is disregarded.
`silent` | flag passed on to `try`, which determines if the error message generated by the checked function is displayed. Queried from global options set for RUnit at package load.
`...` | optional arguments passed to `all.equal` or `all.equal.numeric`

### Details

The check functions are direct equivalents of the various methods of the class junit.framework.Assert of Javas JUnit framework which served as basis for the RUnit package.

For functions defined inside a package equipped with a namespace only exported functions can be accessed inside test cases directly. For functions not exported the only way to test them is to use the '`:::`' operator combined with the package name as a prefix.

Special care is required if test cases are written for S4 classes and methods. If a new class is defined inside a test case via a `setClass` call the class is added to the global class cache and thus available outside the test case. It will persist until explicitly removed via a `removeClass` call. Same applies for new method and generic definitions. Be sure to remove methods and classes in each test case they are defined after the checks have been performed. This is an advise gained from the cumbersome experience: not doing so leads to difficult to pin down error causes incurred from previously executed test cases. For a simple example see the provided test cases in C:/bld/r-runit_1535774530206/_h_env/R/library/RUnit/examples/runitVirtualClassTest.r.

### Author(s)

Thomas König, Klaus Jünemann & Matthias Burger

### See Also

`all.equal`, `all.equal.numeric` and `identical` are the underlying comparison functions. `try` is used for error catching. `.setUp` for details on test case setup. See RUnit-options for global options controlling log out.

### Examples

    checkTrue(1 < 2, "check1")     ## passes fine
    ## checkTrue(1 > 2, "check2")  ## appears as failure in the test protocol

    v <- 1:3
    w <- 1:3
    checkEquals(v, w)               ## passes fine
    names(v) <- c("A", "B", "C")
    ## checkEquals(v, w)            ## fails because v and w have different names
    checkEqualsNumeric(v, w)        ## passes fine because names are ignored

    x <- rep(1:12, 2)
    y <- rep(0:1, 12)
    res <- list(a=1:3, b=letters, LM=lm(y ~ x))
    res2 <- list(a=seq(1,3,by=1), b=letters, LM=lm(y ~ x))
    checkEquals( res, res2)        ## passes fine
    checkIdentical( res, res)
    checkIdentical( res2, res2)
    ## checkIdentical( res, res2)  ## fails because element 'a' differs in type

    fun <- function(x) {
      if(x)
      {
       stop("stop conditions signaled")
      }
      return()
    }

    checkException(fun(TRUE))      ## passes fine
    ## checkException(fun(FALSE))  ## failure, because fun raises no error
    checkException(fun(TRUE), silent=TRUE)

    ##  special constants
    ##  same behaviour as for underlying base functions
    checkEquals(NA, NA)
    checkEquals(NaN, NaN)
    checkEquals(Inf, Inf)

    checkIdentical(NA, NA)
    checkIdentical(NaN, NaN)
    checkIdentical(-Inf, -Inf)

    ## DEACTIVATED("here one can document on the reason for deactivation")

[Package RUnit version 0.4.32 Index]