tests/testthat/test-vis-streamline.R

In metR: Tools for Easier Analysis of Meteorological Fields

skip_on_ci()
skip_if_not_installed("vdiffr")

library(ggplot2)
library(data.table)
library(vdiffr)

context("Streamline")
geo <- geopotential[date == date[1]]
geo[, c("u", "v") := GeostrophicWind(gh, lon, lat)]

basic_geom_streamline <- ggplot(geo, aes(lon, lat)) +
  geom_streamline(
    aes(dx = dlon(u, lat), dy = dlat(v)),
    res = 1 / 3,
    L = 10,
    skip = 2
  )

basic_stat_streamline <- ggplot(geo, aes(lon, lat)) +
  stat_streamline(
    aes(dx = dlon(u, lat), dy = dlat(v)),
    res = 1 / 3,
    L = 10,
    skip = 2
  )

test_that("Streamline works", {
  # skip_on_ci()
  writer_warnings <- function(...) suppressWarnings(vdiffr::write_svg(...))

  expect_warning(
    invisible(print(basic_geom_streamline)),
    "Performing only 1 integration step"
  )
  expect_doppelganger(
    "streamline-base",
    basic_geom_streamline,
    writer = writer_warnings
  )
  expect_doppelganger(
    "streamline-base-stat",
    basic_stat_streamline,
    writer = writer_warnings
  )
})

test_that("Streamline wraps in x amd y", {
  # skip_on_ci()
  expect_doppelganger(
    "streamline-xwrapped",
    ggplot(geo, aes(lon, lat)) +
      geom_streamline(
        aes(dx = u, dy = v),
        L = 20,
        skip = 2,
        res = 1 / 2,
        xwrap = c(0, 360)
      )
  )

  expect_doppelganger(
    "streamline-ywrapped",
    ggplot(geo, aes(lat, lon)) +
      geom_streamline(
        aes(dx = v, dy = u),
        L = 20,
        skip = 2,
        res = 1 / 2,
        ywrap = c(0, 360)
      )
  )
})

test_that("Streamline ignores irregular grids", {
  data <- data.frame(
    lat = rnorm(10),
    lon = rnorm(10),
    u = rnorm(10),
    v = rnorm(10)
  )
  g <- ggplot(data, aes(lon, lat)) +
    geom_streamline(aes(dx = v, dy = u))

  geo <- rbind(na.omit(geo)[1, u := 1], geo)

  g2 <- ggplot(geo, aes(lon, lat)) +
    geom_streamline(aes(dx = dlon(u, lat), dy = dlat(v)), L = 20)

  expect_error(
    invisible(print(g)),
    "'x' and 'y' do not define a regular grid."
  )
  expect_warning(
    invisible(print(g2)),
    "'x' and 'y' do not define a regular grid."
  )

  skip_on_ci()
})