tests/testthat/test-atlas_polygon_converters.R

In ggseg.formats: Brain Atlas Data Structures for the 'ggsegverse' Ecosystem

describe("as_polygon_atlas()", {
  it("converts an sf atlas into the brain_polygons representation", {
    poly <- as_polygon_atlas(dk())
    expect_true(is_atlas_polygon(poly))
    expect_s3_class(atlas_geom(poly), "brain_polygons")
    expect_null(poly$data$sf)
  })

  it("leaves a polygon atlas unchanged", {
    once <- as_polygon_atlas(dk())
    twice <- as_polygon_atlas(once)
    expect_true(is_atlas_polygon(twice))
    expect_setequal(atlas_labels(twice), atlas_labels(once))
  })

  it("errors on non-atlas input", {
    expect_error(as_polygon_atlas(list()), "ggseg_atlas")
  })

  it("errors when the atlas has no 2D geometry", {
    core <- data.frame(hemi = "left", region = "frontal", label = "lh_frontal")
    vertices <- data.frame(label = "lh_frontal")
    vertices$vertices <- list(1L:3L)

    atlas <- ggseg_atlas(
      atlas = "a",
      type = "cortical",
      core = core,
      data = ggseg_data_cortical(vertices = vertices)
    )

    expect_error(as_polygon_atlas(atlas), "no 2D geometry")
  })

  it("points sf-backed atlases at migrate_atlas_files() when sf is missing", {
    sf_atlas <- dk_sf_atlas()
    local_mocked_bindings(has_sf = function() FALSE)
    expect_error(as_polygon_atlas(sf_atlas), "migrate_atlas_files")
  })
})

describe("as_sf_atlas()", {
  it("rehydrates a polygon atlas back into sf", {
    rehy <- as_sf_atlas(as_polygon_atlas(dk()))
    expect_true(is_atlas_sf(rehy))
    expect_s3_class(atlas_geom(rehy), "sf")
  })

  it("preserves region labels through a full round trip", {
    expect_setequal(
      atlas_labels(as_sf_atlas(as_polygon_atlas(dk()))),
      atlas_labels(dk())
    )
  })

  it("errors on non-atlas input", {
    expect_error(as_sf_atlas(list()), "ggseg_atlas")
  })

  it("errors when the atlas has no 2D geometry", {
    core <- data.frame(hemi = "left", region = "frontal", label = "lh_frontal")
    vertices <- data.frame(label = "lh_frontal")
    vertices$vertices <- list(1L:3L)

    atlas <- ggseg_atlas(
      atlas = "a",
      type = "cortical",
      core = core,
      data = ggseg_data_cortical(vertices = vertices)
    )

    expect_error(as_sf_atlas(atlas), "no 2D geometry")
  })
})