The first argument to every
expect_ function can use unquoting to
construct better labels. This makes it easy to create informative labels when
expectations are used inside a function or a for loop.
up the details, returning the expression and label.
A quosure created by
An optional label to override the default. This is only provided for internal usage. Modern expectations should not include a
Argument name shown in error message if
A list containing two elements:
The evaluate value of
The quasiquoted label generated from
expect_ function use unquoting to generate more informative
labels, you can not use unquoting for other purposes. Instead, you'll need
to perform all other unquoting outside of the expectation and only test
f <- function(i) if (i > 3) i * 9 else i * 10 i <- 10 # This sort of expression commonly occurs inside a for loop or function # And the failure isn't helpful because you can't see the value of i # that caused the problem: show_failure(expect_equal(f(i), i * 10)) #> Failed expectation: #> f(i) not equal to i * 10. #> 1/1 mismatches #>  90 - 100 == -10 # To overcome this issue, testthat allows you to unquote expressions using # !!. This causes the failure message to show the value rather than the # variable name show_failure(expect_equal(f(!!i), !!(i * 10))) #> Failed expectation: #> f(10) not equal to 100. #> 1/1 mismatches #>  90 - 100 == -10