问题描述
我在需要一些用户交互的包中创建了一个函数。它基本上会询问用户结果是否符合预期。我想要一个 testthat
-body 来接受输入并创建和检查输出。然而,用户交互阻碍了这个框架。有没有办法以编程方式插入用户答案?我尝试了 interactive()
函数但没有成功。
library(testthat)
# fancy function
askPermission <- function(old,new) {
cat(paste0(old,"\n--->\n",new,"\n\n"))
prompt <- "Use this? "
response <- menu(c("YES","NO"),title = prompt) == 1
return(new)
}
# tests
test_that("test Permission",{
expect_equal(askPermission("A","B"),"B")
})
解决方法
您可以添加一个额外的 response
参数,默认值为 NA
,您可以将其设置为仅在测试期间强制响应:
library(testthat)
# fancy function
askPermission <- function(old,new,response = NA) {
cat(paste0(old,"\n--->\n","\n\n"))
prompt <- "Use this? "
if (is.na(response)) {
response <- menu(c("YES","NO"),title = prompt) == 2
}
return(new)
}
# tests
library(testthat)
test_that("test Permission",{
expect_equal(askPermission("A","B",2),"B")
})
#> A
#> --->
#> B
#>
#> Test passed
另一种选择是使用 mockr
包来模拟 menu
函数:
library(testthat)
library(mockr)
local({
# Here,we override the menu function to force expected choice
local_mock(menu = function(choices,title=NULL) 2)
test_that("test Permission",{
expect_equal(askPermission("A","B"),"B")
})
})
#> A
#> --->
#> B
#>
#> Test passed
请注意,您作为示例提供的 AskPermission
函数始终返回 new
并且不依赖于 response
通过检查调用范围,我找到了一种不使用任何其他依赖项的方法。 test_that()
有自己的函数环境,名为 test_env
。如果在任何更高级别包含此类环境的嵌套作用域中调用函数 askPermission()
,则跳过 menu()
函数。此外,menu()
仅在交互式上下文中才有意义。
library(testthat)
# fancy function
askPermission <- function(old,new) {
cat(paste0(old,"\n\n"))
prompt <- "Use this? "
# calling scope
tb <- .traceback(x = 0)
# check if called in testthat or interactive
if(!any(unlist(lapply(tb,function(x) any(grepl("test_env",x))))) && interactive())
response <- menu(c("YES",title = prompt) == 1
return(new)
}
# tests
test_that("test Permission","B")
})
#> A
#> --->
#> B
#>
#> Test passed
# regular usage --------
askPermission("A","B")
#> A
#> --->
#> B
#> Use this?
#>
#> 1: YES
#> 2: NO
#>
#> Choice: