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// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package geo_test
import (
"testing"
"testing/quick"
"tailscale.com/types/geo"
)
func TestPointAnonymize(t *testing.T) {
t.Run("nowhere", func(t *testing.T) {
var zero geo.Point
p := zero.Quantize()
want := zero.Valid()
if got := p.Valid(); got != want {
t.Fatalf("zero.Valid %t, want %t", got, want)
}
})
t.Run("separation", func(t *testing.T) {
// Walk from the south pole to the north pole and check that each
// point on the latitude is approximately MinSeparation apart.
const southPole = -90 * geo.Degree
const northPole = 90 * geo.Degree
const dateLine = 180 * geo.Degree
llat := southPole
for lat := llat; lat <= northPole; lat += 0x1p-4 {
last := geo.MakePoint(llat, 0)
cur := geo.MakePoint(lat, 0)
anon := cur.Quantize()
switch l, g, err := anon.LatLng(); {
case err != nil:
t.Fatal(err)
case lat == southPole:
// initialize llng, to the first snapped longitude
llat = l
goto Lng
case g != 0:
t.Fatalf("%v is west or east of %v", anon, last)
case l < llat:
t.Fatalf("%v is south of %v", anon, last)
case l == llat:
continue
case l > llat:
switch dist, err := last.DistanceTo(anon); {
case err != nil:
t.Fatal(err)
case dist == 0.0:
continue
case dist < geo.MinSeparation:
t.Logf("lat=%v last=%v cur=%v anon=%v", lat, last, cur, anon)
t.Fatalf("%v is too close to %v", anon, last)
default:
llat = l
}
}
Lng:
llng := dateLine
for lng := llng; lng <= dateLine && lng >= -dateLine; lng -= 0x1p-3 {
last := geo.MakePoint(llat, llng)
cur := geo.MakePoint(lat, lng)
anon := cur.Quantize()
switch l, g, err := anon.LatLng(); {
case err != nil:
t.Fatal(err)
case lng == dateLine:
// initialize llng, to the first snapped longitude
llng = g
continue
case l != llat:
t.Fatalf("%v is north or south of %v", anon, last)
case g != llng:
const tolerance = geo.MinSeparation * 0x1p-9
switch dist, err := last.DistanceTo(anon); {
case err != nil:
t.Fatal(err)
case dist < tolerance:
continue
case dist < (geo.MinSeparation - tolerance):
t.Logf("lat=%v lng=%v last=%v cur=%v anon=%v", lat, lng, last, cur, anon)
t.Fatalf("%v is too close to %v: %v", anon, last, dist)
default:
llng = g
}
}
}
}
if llat == southPole {
t.Fatal("llat never incremented")
}
})
t.Run("quick-check", func(t *testing.T) {
f := func(lat, lng geo.Degrees) bool {
p := geo.MakePoint(lat, lng)
q := p.Quantize()
t.Logf("quantize %v = %v", p, q)
lat, lng, err := q.LatLng()
if err != nil {
t.Errorf("err %v, want nil", err)
return !t.Failed()
}
if lat < -90*geo.Degree || lat > 90*geo.Degree {
t.Errorf("lat outside [-90°, +90°]: %v", lat)
}
if lng < -180*geo.Degree || lng > 180*geo.Degree {
t.Errorf("lng outside [-180°, +180°], %v", lng)
}
if dist, err := p.DistanceTo(q); err != nil {
t.Error(err)
} else if dist > (geo.MinSeparation * 2) {
t.Errorf("moved too far: %v", dist)
}
return !t.Failed()
}
if err := quick.Check(f, nil); err != nil {
t.Fatal(err)
}
})
}
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