tests/testthat/helper-vdiffr.R

In TomeTiger/ggplot2: Create Elegant Data Visualisations Using the Grammar of Graphics

# default is equal to whether NOT_CRAN is true or not
enable_vdiffr <- identical(Sys.getenv("NOT_CRAN"), "true")

# disable or enable vdiffr based on the state of USE_VDIFFR, if set
if (identical(Sys.getenv("USE_VDIFFR"), "true")) {
  enable_vdiffr <- TRUE
} else if (identical(Sys.getenv("USE_VDIFFR"), "false")) {
  enable_vdiffr <- FALSE
}

# disable vdiffr if version is old
if (!requireNamespace("vdiffr", quietly = TRUE) ||
  utils::packageVersion("vdiffr") < "0.2.3.9001") {
  enable_vdiffr <- FALSE
}

expect_doppelganger <- function(title, fig,
                                path = NULL,
                                ...,
                                user_fonts = NULL,
                                verbose = FALSE) {
  if (!enable_vdiffr) {
    expect_error(regexp = NA, ggplot_build(fig))
    return(invisible(NULL))
  }

  vdiffr::expect_doppelganger(title, fig,
    path = path,
    ...,
    user_fonts = user_fonts,
    verbose = verbose
  )
}