Fix standard_error() for skewness and kurtosis from datawizard

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: parameters
 Title: Processing of Model Parameters
-Version: 0.30.0.11
+Version: 0.30.0.12
 Authors@R:
     c(person(given = "Daniel",
              family = "Lüdecke",

NAMESPACE

@@ -811,6 +811,8 @@ S3method(standard_error,cpglmm)
 S3method(standard_error,crch)
 S3method(standard_error,crq)
 S3method(standard_error,data.frame)
+S3method(standard_error,datawizard_kurtosis)
+S3method(standard_error,datawizard_skewness)
 S3method(standard_error,default)
 S3method(standard_error,deltaMethod)
 S3method(standard_error,draws)

NEWS.md

@@ -53,6 +53,9 @@
   this failed with an error. An invalid value for `p_adjust` no longer shows the
   method in the footer of the printed output (#854).
 
+* Fixed issue where `standard_error()` returned `NULL` for objects from
+  `datawizard::skewness()` and `datawizard::kurtosis()`.
+
 # parameters 0.30.0
 
 ## Changes

R/methods_skewness_kurtosis.R

@@ -1,8 +1,19 @@
 #' @export
 standard_error.parameters_skewness <- function(model, ...) {
-  attributes(model)$SE
+  # datawizard returns SE as column, older objects stored it as attribute
+  if ("SE" %in% names(model)) {
+    model$SE
+  } else {
+    attributes(model)$SE
+  }
 }
 
 
 #' @export
 standard_error.parameters_kurtosis <- standard_error.parameters_skewness
+
+#' @export
+standard_error.datawizard_skewness <- standard_error.parameters_skewness
+
+#' @export
+standard_error.datawizard_kurtosis <- standard_error.parameters_skewness

tests/testthat/test-skewness_kurtosis.R

@@ -0,0 +1,25 @@
+skip_if_not_installed("datawizard")
+
+test_that("standard_error returns the SE column of skewness and kurtosis output", {
+  out <- datawizard::skewness(mtcars[c("mpg", "cyl", "disp")])
+  expect_identical(standard_error(out), out$SE)
+  out <- datawizard::kurtosis(mtcars$mpg)
+  expect_identical(standard_error(out), out$SE)
+})
+
+test_that("standard_error works for the datawizard_* classes", {
+  s <- datawizard::skewness(mtcars$mpg)
+  class(s) <- c("datawizard_skewness", "data.frame")
+  expect_identical(standard_error(s), s$SE)
+
+  k <- datawizard::kurtosis(mtcars$mpg)
+  class(k) <- c("datawizard_kurtosis", "data.frame")
+  expect_identical(standard_error(k), k$SE)
+})
+
+test_that("standard_error reads the SE attribute of old objects", {
+  s <- 0.67
+  attr(s, "SE") <- 0.39
+  class(s) <- c("parameters_skewness", "numeric")
+  expect_identical(standard_error(s), 0.39)
+})