context("measures")
test_that("measures", {
  x <- move(x = (dx <- c(1, 1:7)), y = c(1, 1:7), as.POSIXct(c(1:7, 10), origin = "1970-1-1"))
  d <- c(0, rep(sqrt(2), 6))
  t <- c(rep(1, 6), 3)
  expect_equal(distance(x), d)
  expect_equal(speed(x), d / t)
  expect_equal(timeLag(x), t)
  expect_equal(timeLag(x, "secs"), t)
  expect_equal(timeLag(x, "mins"), t / 60)
  expect_warning(xx <- moveStack(list(x, x)))
  expect_equal(distance(xx), list(unnamed = d, unnamed1 = d))
  expect_warning(expect_equal(timeLag(xx), list(unnamed = t, unnamed1 = t)), "Units not specified this could lead to different units for the time differences between individuals")
  expect_equal(speed(xx), list(unnamed = d / t, unnamed1 = d / t))
  expect_warning(turnAngleGc(x), "turnAngleGc is probably not a valid calculation on this projection")
  xx <- x
  proj4string(xx) <- "+proj=longlat +ellps=WGS84"

  expect_equal(distance(xx), (dd <- distGeo(cbind(dx, dx)[-n.locs(xx), ], cbind(dx, dx)[-1, ])))
  expect_equal(speed(xx), dd / t)
  expect_equal(length(turnAngleGc(xx)), n.locs(xx) - 2)
})