Update tests&NEWS.md about epi_slide f Date vec output

Author: lcbrooks

NEWS.md

@@ -25,6 +25,8 @@ inter-release development versions will include an additional ".9999" suffix.
 * `epi_slide` and `epix_slide` now support `as_list_col = TRUE` when the slide
   computations output atomic vectors, and output a list column in "chopped"
   format (see `tidyr::chop`).
+* `epi_slide` now works properly with slide computations that output just a
+  `Date` vector, rather than converting `slide_value` to a numeric column.
 
 # epiprocess 0.6.0
 

tests/testthat/test-epi_slide.R

@@ -292,3 +292,12 @@ test_that("`ref_time_values` + `all_rows = TRUE` works", {
       dplyr::rename(slide_value_value = slide_value)
   )
 })
+
+test_that("`epi_slide` doesn't decay date output", {
+  expect_true(
+    ungrouped %>%
+      epi_slide(before = 5L, ~ as.Date("2020-01-01")) %>%
+      `[[`("slide_value") %>%
+      inherits("Date")
+  )
+})

tests/testthat/test-epix_slide.R

@@ -572,3 +572,15 @@ test_that("epix_slide alerts if the provided f doesn't take enough args", {
   expect_warning(epix_slide(xx, f_x_dots, before = 2L),
     class = "epiprocess__assert_sufficient_f_args__mandatory_f_args_passed_to_f_dots")
 })
+
+test_that("`epix_slide` doesn't decay date output", {
+  expect_true(
+    xx$DT %>%
+      as_tibble() %>%
+      mutate(across(c(time_value, version), ~ as.Date("2000-01-01") + .x - 1L)) %>%
+      as_epi_archive() %>%
+      epix_slide(before = 5L, ~ attr(.x, "metadata")$as_of) %>%
+      `[[`("slide_value") %>%
+      inherits("Date")
+  )
+})