Add tests from book examples of Discovering statistics (#684)

* Add tests from book examples of Discovering statistics

* trigger ci

* trigger again

* remove skip_on_cran()

---------

Co-authored-by: etiennebacher <etienne.bacher@protonmail.com>

Author: strengejacke

DESCRIPTION

@@ -43,6 +43,7 @@ Suggests:
     brms,
     curl,
     data.table,
+    discovr,
     dplyr (>= 1.1),
     effectsize,
     emmeans,

tests/testthat/_snaps/discovr.md

@@ -0,0 +1,12 @@
+# discovr-book-examples, chap 8.8
+
+    Code
+      print(out, table_width = Inf)
+    Output
+      Variable |   Mean |    95% CI (Mean) |     SD |    IQR | Skewness | Kurtosis |   n | n_Missing
+      ----------------------------------------------------------------------------------------------
+      adverts  | 614.41 | [557.21, 686.82] | 485.66 | 696.21 |     0.85 |     0.24 | 200 |         0
+      sales    | 193.20 | [182.70, 203.48] |  80.70 | 117.50 |     0.04 |    -0.68 | 200 |         0
+      airplay  |  27.50 |   [25.92, 29.25] |  12.27 |  16.75 |     0.06 |    -0.03 | 200 |         0
+      image    |   6.77 |     [6.58, 6.98] |   1.40 |   2.00 |    -1.29 |     3.74 | 200 |         0
+

tests/testthat/test-discovr.R

@@ -0,0 +1,13 @@
+skip_if_not_installed("discovr")
+
+test_that("discovr-book-examples, chap 8.8", {
+  data(album_sales, package = "discovr")
+  set.seed(123)
+  out <- describe_distribution(
+    album_sales,
+    range = FALSE,
+    ci = 0.95,
+    iterations = 500
+  )
+  expect_snapshot(print(out, table_width = Inf))
+})