Close #1377: fix ordering of lines in stat_ecdf()

Author: cpsievert

Diff for: R/layers2traces.R

@@ -252,6 +252,7 @@ to_basic.GeomLine <- function(data, prestats_data, layout, params, p, ...) {
 
 #' @export
 to_basic.GeomStep <- function(data, prestats_data, layout, params, p, ...) {
+  data <- data[order(data[["x"]]), ]
   prefix_class(data, "GeomPath")
 }
 

Diff for: tests/testthat/test-ggplot-step.R

@@ -34,3 +34,17 @@ test_that("direction vhv is translated to shape=vhv", {
   expect_equivalent(length(L$data), 2)
   expect_identical(L$data[[1]]$line$shape, "vhv")
 })
+
+
+test_that("`stat_ecdf` renders correctly", {
+  df <- data.frame(
+    x = c(rnorm(100, 0, 3), rnorm(100, 0, 10)),
+    g = gl(2, 100)
+  )
+  
+  p <- ggplot(df, aes(x)) + stat_ecdf(geom = "step")
+  expect_doppelganger(ggplotly(p), "step-ecdf")
+  
+  p <- ggplot(df, aes(x, colour = g)) + stat_ecdf()
+  expect_doppelganger(ggplotly(p), "step-ecdf-multiple")
+})