[英]test_that With match.fun Throws Unexpected Error when Used Two Levels Deep
我在使用中的問題match.fun
連同test_that
時match.fun
被嵌套函數內使用。 為了說明,我已經構建了一個包含兩個函數的快速玩具示例R包。 后者只是稱前者為:
i_dont_throw_error <- function(function_name)
match.fun(function_name)("hello")
i_throw_error <- function(function_name)
i_dont_throw_error(function_name)
然后我寫了testthat
測試如下:
test_that("Testing for an error with match.fun one level deep.",{
print_function <- function(x)
print(x)
expect_equal(i_dont_throw_error("print_function"), "hello")
})
test_that("Testing for an error with match.fun two levels deep.",{
print_function <- function(x)
print(x)
expect_equal(i_throw_error("print_function"), "hello")
})
第一次測試很好,但第二次測試時出錯了。 testthat
的輸出是
==> devtools::test()
Loading testthatTest
Loading required package: testthat
Testing testthatTest
[1] "hello"
.1
1. Error: Testing for an error with match.fun two levels deep. -----------------
object 'print_function' of mode 'function' was not found
1: withCallingHandlers(eval(code, new_test_environment), error = capture_calls, message = function(c) invokeRestart("muffleMessage"))
2: eval(code, new_test_environment)
3: eval(expr, envir, enclos)
4: expect_equal(i_throw_error("print_function"), "hello") at test_test_me.R:12
5: expect_that(object, equals(expected, label = expected.label, ...), info = info, label = label)
6: condition(object)
7: compare(actual, expected, ...)
8: i_throw_error("print_function")
9: i_dont_throw_error(function_name) at C:\Users\jowhitne\Desktop\eraseMe\testthatTest/R/test_func.R:4
10: match.fun(function_name) at C:\Users\jowhitne\Desktop\eraseMe\testthatTest/R/test_func.R:1
11: get(as.character(FUN), mode = "function", envir = envir)
我不明白為什么第一次測試通過但第二次測試失敗。 事實上,直接從控制台運行失敗的測試工作正常:
> print_function <- function(x)
+ print(x)
> i_throw_error("print_function")
[1] "hello"
我知道它與環境有關,但我希望在match.fun
搜索兩個環境之后這可以工作。 知道我在這里缺少什么嗎? 先謝謝您的幫助。
相關問題:
我花了幾個小時來解決這個問題。 這是一個環境問題,與testthat在通過devtools::test()
運行時如何計算表達式有關,但在交互式運行時卻沒有。
testthat在運行測試時創建了許多新環境(以確保不同測試的獨立性,從而避免代碼交互中的錯誤),並且這些環境不會以交互式運行時的方式繼承。 解決方案通常是使用dynGet()
來查找對象,因為它使用黑魔法來查找對象(也就是說我不明白它是如何工作的)。
我根據你的功能創建了一個新的包test.package , 可以在這里復制你的錯誤。 我懷疑這是一個環境問題,因為我過去曾遇到類似的錯誤,我必須認真考慮get()
, parent.frame()
, parent.env()
等。請參閱Hadley的Advanced R中的環境介紹。
不交互運行時調試東西很難。 但是devtools::test()
會向控制台輸出警告,所以我用它來提取調試信息。 這樣做需要我寫一個有點復雜的功能來幫助解決這個問題:
print_envir = function(x, prefix = "", recursive = F, list_objects = T, max_objects = 10, use_names = T, no_attr = T, skip_beyond_global = T) {
# browser()
#use names
if (use_names) {
env_name_attr = attr(x, "name")
if (is.null(env_name_attr)) {
env_name_attr = ""
} else {
env_name_attr = sprintf(" (%s)", env_name_attr)
}
} else {
env_name_attr = ""
}
#strip attributes?
if (no_attr) {
attributes(x) = NULL
}
#get name
env_name = {capture.output(print(x))}
#get parent env name
# parent_env_name = {capture.output(print(parent.env(x)))}
#objects
if (list_objects) {
env_objects = names(x)
#limit
env_objects = na.omit(env_objects[1:max_objects])
#explicit none
if (length(env_objects) == 0) {
env_objects = "(none)"
}
} else {
env_objects = "(not requested)"
}
#issue print as warning so they come thru testthat console
warning(sprintf("%senvironment `%s`%s with objects: %s",
prefix,
env_name,
env_name_attr,
str_c(env_objects, collapse = ", ")
), call. = F)
#recursive?
if (recursive) {
#stop when parent is empty envir
if (!identical(parent.env(x), emptyenv())) {
#skip on top of global?
if (!identical(x, globalenv())) {
print_envir(parent.env(x), recursive = T, list_objects = list_objects, max_objects = max_objects, use_names = use_names, prefix = prefix, no_attr = no_attr)
}
}
}
invisible(NULL)
}
該功能的目的基本上是幫助打印關於在查找對象時搜索的環境的格式良好的警告。 我之所以不使用print()
是,這並沒有顯示在testthat log中的正確位置,而是警告。
首先,我將您的功能重命名並修改為:
inner_func1 = function(function_name) {
#print envirs
print_envir(environment(), "current ", recursive = T)
print_envir(parent.frame(), "parent.frame ", recursive = T)
match.fun(function_name)("hello")
}
outer_func1 = function(function_name) {
#print envirs
print_envir(environment(), "current ", recursive = T)
print_envir(parent.frame(), "parent.frame ", recursive = T)
print_envir(environment(inner_func1), "defining/enclosing ", recursive = T)
#failing call
inner_func1(function_name)
}
因此,它現在在您評估時打印(作為警告)2/3環境及其父母。 對於outer_v1
,控制台輸出如下outer_v1
:
test_functions.R:13: warning: outer_v1
current environment `<environment: 0x397a2a8>` with objects: function_name
test_functions.R:13: warning: outer_v1
current environment `<environment: namespace:test.package>` with objects: print_envir, .__DEVTOOLS__, inner_func1, .packageName, inner_func2, inner_func3, outer_func1, outer_func2, outer_func3, .__NAMESPACE__.
test_functions.R:13: warning: outer_v1
current environment `<environment: 0x23aa1a0>` with objects: library.dynam.unload, system.file
test_functions.R:13: warning: outer_v1
current environment `<environment: namespace:base>` with objects: Sys.Date, c.warnings, as.expression.default, as.POSIXlt.factor, [.hexmode, unique.warnings, dimnames<-, regexpr, !, parse
test_functions.R:13: warning: outer_v1
current environment `<environment: R_GlobalEnv>` with objects: .Random.seed
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: 0x313b150>` with objects: (none)
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: 0x3d25070>` with objects: print_function
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: 0x3cff218>` with objects: (none)
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: 0x370c908>` with objects: (none)
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: namespace:test.package>` with objects: print_envir, .__DEVTOOLS__, inner_func1, .packageName, inner_func2, inner_func3, outer_func1, outer_func2, outer_func3, .__NAMESPACE__.
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: 0x23aa1a0>` with objects: library.dynam.unload, system.file
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: namespace:base>` with objects: Sys.Date, c.warnings, as.expression.default, as.POSIXlt.factor, [.hexmode, unique.warnings, dimnames<-, regexpr, !, parse
test_functions.R:13: warning: outer_v1
parent.frame environment `<environment: R_GlobalEnv>` with objects: .Random.seed
test_functions.R:13: warning: outer_v1
defining/enclosing environment `<environment: namespace:test.package>` with objects: print_envir, .__DEVTOOLS__, inner_func1, .packageName, inner_func2, inner_func3, outer_func1, outer_func2, outer_func3, .__NAMESPACE__.
test_functions.R:13: warning: outer_v1
defining/enclosing environment `<environment: 0x23aa1a0>` with objects: library.dynam.unload, system.file
test_functions.R:13: warning: outer_v1
defining/enclosing environment `<environment: namespace:base>` with objects: Sys.Date, c.warnings, as.expression.default, as.POSIXlt.factor, [.hexmode, unique.warnings, dimnames<-, regexpr, !, parse
test_functions.R:13: warning: outer_v1
defining/enclosing environment `<environment: R_GlobalEnv>` with objects: .Random.seed
(skipped because these are from inner_v1)
test_functions.R:13: error: outer_v1
object 'print_function' of mode 'function' was not found
1: expect_equal(outer_func1("print_function"), "hello") at /4tb/GP/code/test.package/tests/testthat/test_functions.R:13
2: quasi_label(enquo(object), label)
3: eval_bare(get_expr(quo), get_env(quo))
4: outer_func1("print_function")
5: inner_func1(function_name) at /code/test.package/R/functions.R:62
6: match.fun(function_name) at /code/test.package/R/functions.R:7
7: get(as.character(FUN), mode = "function", envir = envir)
這很長,但它分為4個部分:3個與環境的遞歸打印有關的部分,以及最后發生的錯誤。 環境標有在函數定義中看到的前綴,因此很容易看到發生了什么。 例如, current environment
是當前(在函數調用內)環境。
通過三個列表,我們找到了這些路徑:
0x397a2a8
(function environment)> namespace:test.package
> 0x23aa1a0
> namespace:base
> R_GlobalEnv
。 這些都沒有我們想要的對象,即print_function
。 0x3d25070
(一個空的環境,不知道它為什么會出現)> 0x3d25070
(有我們的對象!)> 0x3cff218
(另一個空環境)> 0x370c908
(還有一個)> namespace:test.package
> 0x23aa1a0
> namespace:base
> R_GlobalEnv
。 namespace:test.package
/ enclosing: namespace:test.package
> 0x23aa1a0
> namespace:base
> R_GlobalEnv
。 定義/封閉和父框架的路徑重疊,前者是后者的子集。 事實證明我們的對象在parent.frame中,但是有2步。 因此,在這種情況下,我們可以使用get(function_name, envir = parent.frame(n = 2))
來獲取函數。 因此,第二次迭代是:
inner_func2 = function(function_name) {
#print envirs
print_envir(environment(), "current ", recursive = T)
print_envir(parent.frame(), "parent.frame ", recursive = T)
#try to get object in current envir
#if it isnt there, try parent.frame
if (exists(function_name)) {
warning(sprintf("%s exists", function_name))
func = get(function_name)
} else {
warning(sprintf("%s does not exist", function_name))
func = get(function_name, envir = parent.frame(n = 2))
}
func("hello")
}
outer_func2 = function(function_name) {
#print envirs
print_envir(environment(), "current ", recursive = T)
print_envir(parent.frame(), "parent.frame ", recursive = T)
print_envir(environment(inner_func2), "defining/enclosing ", recursive = T)
inner_func2(function_name)
}
這仍然是交互式的,因為我們添加了一個if子句,它首先嘗試以正常方式找到它,然后如果沒有,則嘗試parent.frame(n = 2)
方式。
在通過devtools::test()
我們發現outer_v2
現在可以正常工作但我們打破了inner_v2
雖然它以交互方式工作。 如果我們檢查日志,我們會看到:
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: 0x41f0d78>` with objects: (none)
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: 0x478aa60>` with objects: print_function
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: 0x47546d0>` with objects: (none)
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: 0x4152c20>` with objects: (none)
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: namespace:test.package>` with objects: print_envir, .__DEVTOOLS__, inner_func1, .packageName, inner_func2, inner_func3, outer_func1, outer_func2, outer_func3, .__NAMESPACE__.
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: 0x2df41a0>` with objects: library.dynam.unload, system.file
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: namespace:base>` with objects: Sys.Date, c.warnings, as.expression.default, as.POSIXlt.factor, [.hexmode, unique.warnings, dimnames<-, regexpr, !, parse
test_functions.R:20: warning: inner_v2
parent.frame environment `<environment: R_GlobalEnv>` with objects: .Random.seed
test_functions.R:20: warning: inner_v2
print_function does not exist
test_functions.R:20: error: inner_v2
object 'print_function' not found
1: expect_equal(inner_func2("print_function"), "hello") at /code/test.package/tests/testthat/test_functions.R:20
2: quasi_label(enquo(object), label)
3: eval_bare(get_expr(quo), get_env(quo))
4: inner_func2("print_function")
5: get(function_name, envir = parent.frame(n = 2)) at /code/test.package/R/functions.R:23
所以我們的目標是兩步,但我們仍然想念它。 怎么樣? 好吧,我們從不同的地方parent.frame(n = 2)
,這改變了一些東西。 如果我們用parent.frame(n = 1)
替換它,它再次起作用。
因此,使用parent.frame()
並不是一個徹底的解決方案,因為需要知道要返回多少步驟,這取決於一個嵌套函數的數量。 有沒有更好的辦法? 是。 dynGet()
使用黑魔法自己解決這個問題(即我不知道它是如何工作的)。 人們可以想必也是通過實現自定義實現這一目標get2()
通過所有可能的值循環為n
在parent.frame()
左為讀者做練習)。
因此,我們的最終版本的功能是:
inner_func3 = function(function_name) {
#print envirs
print_envir(environment(), "current ", recursive = T)
print_envir(parent.frame(), "parent.frame ", recursive = T)
#try to get object in current envir
#if it isnt there, try parent.frame
if (exists(function_name)) {
warning(sprintf("%s exists", function_name))
func = get(function_name)
} else {
warning(sprintf("%s does not exist", function_name))
func = dynGet(function_name)
}
func("hello")
}
outer_func3 = function(function_name) {
#print envirs
print_envir(environment(), "current ", recursive = T)
print_envir(parent.frame(), "parent.frame ", recursive = T)
print_envir(environment(inner_func3), "defining/enclosing ", recursive = T)
inner_func3(function_name)
}
這些傳遞了交互式和devtools::test()
測試。 萬歲!
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