如何确保单元测试中的英语错误消息 [英] How to ensure english error messages in testthat unit tests

问题描述

我有很多使用testthat软件包的单元测试，它们会出现英语错误消息.

I have a lot of unit tests using the testthat package that expect english error messages.

如果其他开发人员在配置为非英语语言环境的计算机上运行测试，则会以另一种语言发出错误消息，并且我的测试失败.

If other developer run the tests on a computer configured for a non-english locale the error message are emitted in a different language and my tests fail.

我如何初始化testthat以仅在测试运行时更改语言设置，而无需从R外部手动或永久更改语言或测试环境(例如此处建议的内容:

How can I initialize testthat to change the language settings only during the test run-time without manually or permanently changing the language or test environment from outside of R (like e. g. proposed here: in R how to get error messages in english)?

library(testthat)
# works only in english locales...
expect_error(log("a"), "non-numeric argument to mathematical function", fixed = TRUE)

:在运行时更改语言环境不会更改错误消息的语言(使用Ubuntu和OSX High Sierra):

Edit 1: Changing the locale during run-time does not change the language of the error messages (using Ubuntu and OSX High Sierra):

Sys.setlocale( locale = "en_US.UTF-8")
Sys.getlocale()  # en_US is active now but messages are still in another language

似乎Sys.setenv("LANGUAGE"="EN")似乎立即更改了错误消息的语言(使用OSX测试).我应该在哪里放置此命令以进行测试?在testthat.R文件中?

Edit 2: It seems that Sys.setenv("LANGUAGE"="EN") seems to change the error message language immediately (tested using OSX). Where should I put this command for testthat? In the testthat.R file?

R控制台为德语，如何将R设置为英语?

作为我提出的第一个解决方法

Edit 3: As a first work-around I have put

Sys.setenv("LANGUAGE"="EN")  # work-around to always create english R (error) messages

进入我的testthat.R文件在tests文件夹下(这似乎可以工作，但是我不确定这是正确还是最好的方法...

into my testthat.R file under the tests folder (it seems to work but I am not sure whether this is the right or best way...

推荐答案

设置Sys.setenv("LANGUAGE" = "EN")同样适用于我.

但是，当使用devtools::test()进行测试时-就像Rstudio中的ctrl + shift + T一样-我必须在 tests/testthat/目录中的测试脚本中调用Sys.setenv().原因是devtools::test()将绕过 tests/testthat.R 文件调用testthat::test_dir().

However, when testing with devtools::test() - as ctrl + shift + T in Rstudio will do - I had to call Sys.setenv() in the test scripts inside the tests/testthat/ directory. The reason being that devtools::test() will call testthat::test_dir() circumventing the tests/testthat.R file.

到目前为止，这还没有不良副作用.如

So far, this did not have undesirable side-effects. The environment variable will only be set for that particular R process as described in the help page:

Sys.setenv设置环境变量(用于从R内调用的其他进程或此R进程对Sys.getenv的将来调用).

Sys.setenv sets environment variables (for other processes called from within R or future calls to Sys.getenv from this R process).

为完整起见，您还可以在Windows上再次取消设置变量(请参见注释).

For completeness, you can also unset the variable again on Windows (see comments).

  Sys.setenv("LANGUAGE" = "DE")
  expect_error(log("a"), "Nicht-numerisches Argument")
  Sys.setenv("LANGUAGE" = "FR")
  expect_error(log("a"), "argument non numérique ")
  Sys.unsetenv("LANGUAGE")

RStudio可能还会带来麻烦(我无法以交互方式更改那里的语言)，但是在使用devtools::test()执行时它可以工作.

RStudio might also give trouble (I was not able to change the language there interactively), but when executing with devtools::test() it works.

最后，将其包装在辅助函数中.

Finally, wrapping it in a helper function.

expect_error_lang <- function(..., lang = "EN") {
    Sys.setenv("LANGUAGE" = lang)
    expect_error(...)
    Sys.unsetenv("LANGUAGE")
  }
#...
expect_error_lang(log("a"), "non-numeric")
expect_error_lang(log("a"), "Nicht-numerisches", lang = "DE")
expect_error_lang(log("a"), "argument non", lang = "FR")

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