use %OS for printing time (#81)

- Date columns now show sub-seconds if the `digits.secs` option is set (#74).

R/shaft.R

@@ -111,7 +111,7 @@ pillar_shaft.Date <- function(x, ...) {
 #' @rdname pillar_shaft
 pillar_shaft.POSIXt <- function(x, ...) {
   date <- format(x, format = "%Y-%m-%d")
-  time <- format(x, format = "%H:%M:%S")
+  time <- format(x, format = "%H:%M:%OS")
 
   datetime <- paste0(date, " " , style_subtle(time))
   datetime[is.na(x)] <- NA

tests/testthat/helper-output.R

@@ -10,7 +10,7 @@ df_all <- list(
   d = c("a", "b", NA),
   e = factor(c("a", "b", NA)),
   f = as.Date("2015-12-09") + c(1:2, NA),
-  g = as.POSIXct("2015-12-09 10:51:34 UTC") + c(1:2, NA),
+  g = as.POSIXct("2015-12-09 10:51:34.5678 UTC") + c(1:2, NA),
   h = as.list(c(1:2, NA)),
   i = list(list(1, 2:3), list(4:6), list(NA))
 )

tests/testthat/out/tibble-all-digits-secs.txt

@@ -0,0 +1,5 @@
+  g                  
+  <dttm>             
+1 2015-12-09 10:51:35.56780
+2 2015-12-09 10:51:36.56780
+3 NA                 

tests/testthat/test-format_multi.R

@@ -144,3 +144,15 @@ test_that("empty", {
     structure(character(), class = "pillar_vertical")
   )
 })
+
+
+test_that("option(digits.secs) (#74)", {
+  withr::with_options(
+    list(digits.secs = 5),
+    expect_pillar_output(
+      crayon = FALSE,
+      xf = colonnade(df_all["g"]),
+      filename = "tibble-all-digits-secs.txt"
+    )
+  )
+})