circle_test.go

package geom_test

import (
	"testing"

	"github.com/go-spatial/geom"

	cmppkg "github.com/go-spatial/geom/cmp"
)

func TestCircleFromPoints(t *testing.T) {
	type tcase struct {
		p      [3][2]float64
		circle geom.Circle
		err    error
		cmp    *cmppkg.Compare
	}
	fn := func(tc tcase) func(*testing.T) {
		cmp := cmppkg.DefaultCompare()
		if tc.cmp != nil {
			cmp = *tc.cmp
		}
		return func(t *testing.T) {

			circle, err := geom.CircleFromPoints(tc.p[0], tc.p[1], tc.p[2])
			if (tc.err != nil && err == nil) || (tc.err == nil && err != nil) {
				t.Errorf("error, expected %v got %v", tc.err, err)
				return
			}
			if tc.err != nil {
				if tc.err != err {
					t.Errorf("error, expected %v got %v", tc.err, err)
				}
				return
			}

			if !cmp.Float(circle.Radius, tc.circle.Radius) {
				t.Errorf("circle radius, expected %v got %v", tc.circle, circle)
				return
			}

			if !cmp.Float(circle.Center[0], tc.circle.Center[0]) {
				t.Errorf("circle x, expected %v got %v", tc.circle, circle)
				return
			}

			if !cmp.Float(circle.Center[1], tc.circle.Center[1]) {
				t.Errorf("circle y, expected %v got %v", tc.circle, circle)
				return
			}
		}
	}

	tests := map[string]tcase{
		"simple colinear": {
			p:   [3][2]float64{{1, 0}, {1, 1}, {1, 20}},
			err: geom.ErrPointsAreCoLinear,
		},
		"center outside of triangle": {
			p:      [3][2]float64{{1, 0}, {10, 20}, {5, 5}},
			circle: geom.Circle{Center: [2]float64{-21.642857, 22.214286}, Radius: 31.7202},
		},
		"center outside of triangle 1": {
			p:      [3][2]float64{{1, 0}, {5, 5}, {10, 20}},
			circle: geom.Circle{Center: [2]float64{-21.642857, 22.214286}, Radius: 31.7202},
		},
		"center outside of triangle 2": {
			p:      [3][2]float64{{5, 5}, {1, 0}, {10, 20}},
			circle: geom.Circle{Center: [2]float64{-21.642857, 22.214286}, Radius: 31.7202},
		},
		"center right triangle": {
			p:      [3][2]float64{{1, 0}, {10, 0}, {10, 7}},
			circle: geom.Circle{Center: [2]float64{5.5, 3.5}, Radius: 5.7009},
		},
		"center right triangle 1": {
			p:      [3][2]float64{{10, 0}, {1, 0}, {10, 7}},
			circle: geom.Circle{Center: [2]float64{5.5, 3.5}, Radius: 5.7009},
		},
	}
	for name, tc := range tests {
		t.Run(name, fn(tc))
	}
}