atExpectStop
Verify That an Expression Causes an Error

### Description

Evaluate an expression and return TRUE if it throws the expected error message.

### Usage

       atExpectStop(expr, expected = ".")

### Arguments

expr | An expression to evaluate. It will be taken literally, as in system.time().
expected | A regular expression that matches the expected error message. See regexpr for the syntax; "." matches any message.

Value
TRUE if the expression causes the expected message. Otherwise a string describing the discrepency. This is the type of output that assertionTest requires.
See Also
atExpectWarnings does a similar job for warnings.
Examples

    ## Not run:
    # The following may be put into a test.t file
    # and run by assertionTest.  The first should return TRUE.
    atExpectStop(lm(y ~ noSuchData), expected="noSuchData.*not found")
    # expect complaints from the following two:
    atExpectStop(stop("Oops"), expected="a problem happened")
    atExpectStop(1L+2L == 3L, expected="integer arithment overflow")
    # Run example test files in assertionTest/test-ex
    assertionTest(system.file(package="assertionTest", "test-ex", "allbad.t"))

    ## End(Not run)

Package assertionTest version 6.1.5-18
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