added boxplot for (grouped) freq()

tests/testthat/test-freq.R

@@ -47,7 +47,10 @@ test_that("frequency table works", {
   expect_output(print(freq(septic_patients$age, markdown = TRUE, title = "TITLE")))
 
   # character
-  expect_output(suppressWarnings(print(freq(microorganisms$fullname))))
+  expect_output(print(freq(microorganisms$genus)))
+  expect_output(print(structure(freq(microorganisms$genus),
+                                # check printing of old class:
+                                class = c("frequency_tbl", "data.frame"))))
   # mo
   expect_output(print(freq(septic_patients$mo)))
   # rsi
@@ -121,9 +124,11 @@ test_that("frequency table works", {
   # input must be freq tbl
   expect_error(septic_patients %>% top_freq(1))
 
-  # charts from plot and hist, should not raise errors
+  # charts from plot, hist and boxplot, should not raise errors
   plot(freq(septic_patients, age))
   hist(freq(septic_patients, age))
+  boxplot(freq(septic_patients, age))
+  boxplot(freq(dplyr::group_by(septic_patients, gender), age))
 
   # check vector
   expect_identical(septic_patients %>%