add first test for mergeRing

geom/ring.go

@@ -85,7 +85,7 @@ func mergeRings(rings []*Ring) []*Ring {
 	for _, ring := range endpoints {
 		uniqueRings[ring] = true
 	}
-	result := make([]*Ring, len(uniqueRings))
+	result := make([]*Ring, 0, len(uniqueRings))
 	for ring, _ := range uniqueRings {
 		result = append(result, ring)
 	}

geom/ring_test.go

@@ -0,0 +1,41 @@
+package geom
+
+import (
+	"goposm/element"
+	"testing"
+)
+
+func TestRingMerge(t *testing.T) {
+	w1 := element.Way{}
+	w1.Id = 1
+	w1.Refs = []int64{1, 2, 3}
+	nodes := []*element.Node{
+		&element.Node{},
+		&element.Node{},
+		&element.Node{},
+	}
+	r1 := Ring{[]*element.Way{&w1}, w1.Refs, nodes}
+
+	w2 := element.Way{}
+	w2.Id = 2
+	w2.Refs = []int64{3, 4, 1}
+	nodes = []*element.Node{
+		&element.Node{},
+		&element.Node{},
+		&element.Node{},
+	}
+	r2 := Ring{[]*element.Way{&w2}, w2.Refs, nodes}
+	rings := []*Ring{&r1, &r2}
+
+	result := mergeRings(rings)
+	if len(result) != 1 {
+		t.Fatal(result)
+	}
+	r := result[0]
+	expected := []int64{1, 2, 3, 4, 1}
+	for i, ref := range r.refs {
+		if ref != expected[i] {
+			t.Fatalf("%v != %v", r.refs, expected)
+		}
+	}
+}