st/vendor/github.com/kellydunn/golang-geo/point_test.go
2015-09-29 01:14:03 -07:00

139 lines
3.8 KiB
Go

package geo
import (
"encoding/json"
"fmt"
"log"
"testing"
)
// Tests that a call to NewPoint should return a pointer to a Point with the specified values assigned correctly.
func TestNewPoint(t *testing.T) {
p := NewPoint(40.5, 120.5)
if p == nil {
t.Error("Expected to get a pointer to a new point, but got nil instead.")
}
if p.lat != 40.5 {
t.Errorf("Expected to be able to specify 40.5 as the lat value of a new point, but got %f instead", p.lat)
}
if p.lng != 120.5 {
t.Errorf("Expected to be able to specify 120.5 as the lng value of a new point, but got %f instead", p.lng)
}
}
// Tests that calling GetLat() after creating a new point returns the expected lat value.
func TestLat(t *testing.T) {
p := NewPoint(40.5, 120.5)
lat := p.Lat()
if lat != 40.5 {
t.Error("Expected a call to GetLat() to return the same lat value as was set before, but got %f instead", lat)
}
}
// Tests that calling GetLng() after creating a new point returns the expected lng value.
func TestLng(t *testing.T) {
p := NewPoint(40.5, 120.5)
lng := p.Lng()
if lng != 120.5 {
t.Error("Expected a call to GetLng() to return the same lat value as was set before, but got %f instead", lng)
}
}
// Seems brittle :\
func TestGreatCircleDistance(t *testing.T) {
// Test that SEA and SFO are ~ 1091km apart, accurate to 100 meters.
sea := &Point{lat: 47.4489, lng: -122.3094}
sfo := &Point{lat: 37.6160933, lng: -122.3924223}
sfoToSea := 1093.379199082169
dist := sea.GreatCircleDistance(sfo)
if !(dist < (sfoToSea+0.1) && dist > (sfoToSea-0.1)) {
t.Error("Unnacceptable result.", dist)
}
}
func TestPointAtDistanceAndBearing(t *testing.T) {
sea := &Point{lat: 47.44745785, lng: -122.308065668024}
p := sea.PointAtDistanceAndBearing(1090.7, 180)
// Expected results of transposing point
// ~1091km at bearing of 180 degrees
resultLat := 37.638557
resultLng := -122.308066
withinLatBounds := p.lat < resultLat+0.001 && p.lat > resultLat-0.001
withinLngBounds := p.lng < resultLng+0.001 && p.lng > resultLng-0.001
if !(withinLatBounds && withinLngBounds) {
t.Error("Unnacceptable result.", fmt.Sprintf("[%f, %f]", p.lat, p.lng))
}
}
func TestBearingTo(t *testing.T) {
p1 := &Point{lat: 40.7486, lng: -73.9864}
p2 := &Point{lat: 0.0, lng: 0.0}
bearing := p1.BearingTo(p2)
// Expected bearing 60 degrees
resultBearing := 100.610833
withinBearingBounds := bearing < resultBearing+0.001 && bearing > resultBearing-0.001
if !withinBearingBounds {
t.Error("Unnacceptable result.", fmt.Sprintf("%f", bearing))
}
}
func TestMidpointTo(t *testing.T) {
p1 := &Point{lat: 52.205, lng: 0.119}
p2 := &Point{lat: 48.857, lng: 2.351}
p := p1.MidpointTo(p2)
// Expected midpoint 50.5363°N, 001.2746°E
resultLat := 50.53632
resultLng := 1.274614
withinLatBounds := p.lat < resultLat+0.001 && p.lat > resultLat-0.001
withinLngBounds := p.lng < resultLng+0.001 && p.lng > resultLng-0.001
if !(withinLatBounds && withinLngBounds) {
t.Error("Unnacceptable result.", fmt.Sprintf("[%f, %f]", p.lat, p.lng))
}
}
// Enures that a point can be marhalled into JSON
func TestMarshalJSON(t *testing.T) {
p := NewPoint(40.7486, -73.9864)
res, err := json.Marshal(p)
if err != nil {
log.Print(err)
t.Error("Should not encounter an error when attempting to Marshal a Point to JSON")
}
if string(res) != `{"lat":40.7486,"lng":-73.9864}` {
t.Error("Point should correctly Marshal to JSON")
}
}
// Enures that a point can be unmarhalled from JSON
func TestUnmarshalJSON(t *testing.T) {
data := []byte(`{"lat":40.7486,"lng":-73.9864}`)
p := &Point{}
err := p.UnmarshalJSON(data)
if err != nil {
t.Errorf("Should not encounter an error when attempting to Unmarshal a Point from JSON")
}
if p.lat != 40.7486 || p.lng != -73.9864 {
t.Errorf("Point has mismatched data after Unmarshalling from JSON")
}
}