Tests break with upcoming ggplot2 version

[teunbrand]

Hi there,

I apologise for ignoring your preformatted issue template.
We've been preparing a new major release for ggplot2 and found an issue during a reverse dependency check.
The issue occurs in tests like the one indicated below:

ggplot2.utils/tests/testthat/test-stat_km_ticks.R

Lines 10 to 17 in 1998fe9

	expect_named(
	first_layer,
	c(
	"x", "y", "time", "survival", "n.risk", "n.censor", "n.event",
	"PANEL", "group", "shape", "colour", "size", "alpha",
	"stroke", "fill"
	)
	)

The order of the columns of layer data is not guaranteed and it is even possible that we add more columns in some cases. Such changes may not break your plot, but will break this test. We recommend you choose another testing strategy not relying on internal structures of ggplot to ensure the correctness of your code.

You can test your code with the development version of ggplot2 by installing it as follows:

# install.packages("pak")
pak::pak("tidyverse/ggplot2")

We aim to release the new ggplot2 version in about 2 weeks, and hope you can submit an update to CRAN around that time. Hopefully this will inform you in a timely manner.

Best wishes,
Teun