tests/testthat/test-fill_bone_points.R

In BoneDensityMapping: Maps Bone Densities from CT Scans to Surface Models

url <- "https://github.com/Telfer/BoneDensityMapping/releases/download/v1.0.2/test_CT_femur.stl"
bone_filepath <- tempfile(fileext = ".stl")
download.file(url, bone_filepath, mode = "wb")
surface_mesh <- import_mesh(bone_filepath)

url2 <- "https://github.com/Telfer/BoneDensityMapping/releases/download/v1.0.1/test_CT_hip.nii.gz"
scan_filepath <- tempfile(fileext = ".nii.gz")
download.file(url2, scan_filepath, mode = "wb")
nifti <- import_scan(scan_filepath)

test_that("fill_bone_points returns correct point matrix", {
  # Run fill_bone_points with spacing 10
  points <- fill_bone_points(surface_mesh, spacing = 10)

  # Test 1: output is matrix
  expect_true(is.matrix(points))

  # Test 2: points are within bounding box of mesh vertices (plus small margin)
  verts <- t(surface_mesh$vb)[, 1:3]
  margin <- 0.01
  expect_true(all(points[,1] >= min(verts[,1]) - margin))
  expect_true(all(points[,1] <= max(verts[,1]) + margin))
  expect_true(all(points[,2] >= min(verts[,2]) - margin))
  expect_true(all(points[,2] <= max(verts[,2]) + margin))
  expect_true(all(points[,3] >= min(verts[,3]) - margin))
  expect_true(all(points[,3] <= max(verts[,3]) + margin))

  # Test 3: some points returned
  expect_gt(nrow(points), 0)

  # Test 4: number of points returned is not greater than total points in grid
  x <- seq(min(verts[,1]), max(verts[,1]), by = 10)
  y <- seq(min(verts[,2]), max(verts[,2]), by = 10)
  z <- seq(min(verts[,3]), max(verts[,3]), by = 10)
  expect_lte(nrow(points), length(x) * length(y) * length(z))
})