weatherfeeder/internal/geo/point_test.go

package geo

import (
	"encoding/json"
	"strings"
	"testing"
)

const squarePolygon = `{
  "type": "Polygon",
  "coordinates": [[
    [-91.0, 38.0],
    [-90.0, 38.0],
    [-90.0, 39.0],
    [-91.0, 39.0],
    [-91.0, 38.0]
  ]]
}`

func TestContainsPointInsideSimplePolygon(t *testing.T) {
	got, err := ContainsPoint([]byte(squarePolygon), Point{Longitude: -90.5, Latitude: 38.5})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if !got {
		t.Fatalf("ContainsPoint() = false, want true")
	}
}

func TestContainsPointAcceptsRawMessage(t *testing.T) {
	got, err := ContainsPoint(json.RawMessage(squarePolygon), Point{Longitude: -90.5, Latitude: 38.5})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if !got {
		t.Fatalf("ContainsPoint() = false, want true")
	}
}

func TestContainsPointOutsideSimplePolygon(t *testing.T) {
	got, err := ContainsPoint([]byte(squarePolygon), Point{Longitude: -89.5, Latitude: 38.5})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if got {
		t.Fatalf("ContainsPoint() = true, want false")
	}
}

func TestContainsPointOnBoundary(t *testing.T) {
	got, err := ContainsPoint([]byte(squarePolygon), Point{Longitude: -91.0, Latitude: 38.5})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if !got {
		t.Fatalf("ContainsPoint() = false, want true")
	}
}

func TestContainsPointInHoleReturnsFalse(t *testing.T) {
	const polygonWithHole = `{
  "type": "Polygon",
  "coordinates": [
    [[0,0],[10,0],[10,10],[0,10],[0,0]],
    [[4,4],[6,4],[6,6],[4,6],[4,4]]
  ]
}`

	got, err := ContainsPoint([]byte(polygonWithHole), Point{Longitude: 5, Latitude: 5})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if got {
		t.Fatalf("ContainsPoint() = true, want false")
	}
}

func TestContainsPointOnHoleBoundaryReturnsTrue(t *testing.T) {
	const polygonWithHole = `{
  "type": "Polygon",
  "coordinates": [
    [[0,0],[10,0],[10,10],[0,10],[0,0]],
    [[4,4],[6,4],[6,6],[4,6],[4,4]]
  ]
}`

	got, err := ContainsPoint([]byte(polygonWithHole), Point{Longitude: 4, Latitude: 5})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if !got {
		t.Fatalf("ContainsPoint() = false, want true")
	}
}

func TestContainsPointInsideOneMultiPolygonMember(t *testing.T) {
	const multiPolygon = `{
  "type": "MultiPolygon",
  "coordinates": [
    [[[0,0],[1,0],[1,1],[0,1],[0,0]]],
    [[[10,10],[12,10],[12,12],[10,12],[10,10]]]
  ]
}`

	got, err := ContainsPoint([]byte(multiPolygon), Point{Longitude: 11, Latitude: 11})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if !got {
		t.Fatalf("ContainsPoint() = false, want true")
	}
}

func TestContainsPointUsesLongitudeLatitudeOrder(t *testing.T) {
	const narrowPolygon = `{
  "type": "Polygon",
  "coordinates": [[
    [-91.0, 38.0],
    [-90.0, 38.0],
    [-90.0, 39.0],
    [-91.0, 39.0],
    [-91.0, 38.0]
  ]]
}`

	got, err := ContainsPoint([]byte(narrowPolygon), Point{Longitude: -90.5, Latitude: 38.5})
	if err != nil {
		t.Fatalf("ContainsPoint() error = %v", err)
	}
	if !got {
		t.Fatalf("ContainsPoint() = false, want true")
	}

	got, err = ContainsPoint([]byte(narrowPolygon), Point{Longitude: 38.5, Latitude: -90.5})
	if err != nil {
		t.Fatalf("ContainsPoint() reversed error = %v", err)
	}
	if got {
		t.Fatalf("ContainsPoint() with reversed coordinate values = true, want false")
	}
}

func TestContainsPointUnsupportedGeometryError(t *testing.T) {
	_, err := ContainsPoint([]byte(`{"type":"Point","coordinates":[-90,38]}`), Point{Longitude: -90, Latitude: 38})
	if err == nil {
		t.Fatalf("ContainsPoint() error = nil, want error")
	}
	if !strings.Contains(err.Error(), `unsupported geojson geometry type "Point"`) {
		t.Fatalf("ContainsPoint() error = %q", err)
	}
}

func TestContainsPointInvalidJSONError(t *testing.T) {
	_, err := ContainsPoint([]byte(`{"type":"Polygon"`), Point{Longitude: -90, Latitude: 38})
	if err == nil {
		t.Fatalf("ContainsPoint() error = nil, want error")
	}
	if !strings.Contains(err.Error(), "decode geojson geometry") {
		t.Fatalf("ContainsPoint() error = %q", err)
	}
}

func TestContainsPointMalformedCoordinatesError(t *testing.T) {
	_, err := ContainsPoint([]byte(`{"type":"Polygon","coordinates":[[[1]]]}`), Point{Longitude: 1, Latitude: 1})
	if err == nil {
		t.Fatalf("ContainsPoint() error = nil, want error")
	}
	if !strings.Contains(err.Error(), "need longitude and latitude") {
		t.Fatalf("ContainsPoint() error = %q", err)
	}
}

func TestContainsPointEmptyRingError(t *testing.T) {
	_, err := ContainsPoint([]byte(`{"type":"Polygon","coordinates":[[]]}`), Point{Longitude: 1, Latitude: 1})
	if err == nil {
		t.Fatalf("ContainsPoint() error = nil, want error")
	}
	if !strings.Contains(err.Error(), "ring has no points") {
		t.Fatalf("ContainsPoint() error = %q", err)
	}
}