added test for all implementations

internal/bsp/build_test.go

@@ -0,0 +1,97 @@
+package bsp
+
+import (
+	"math"
+	"testing"
+
+	"bspviz/internal/geom"
+)
+
+func TestStopUsesDefaults(t *testing.T) {
+	segs := make([]geom.Seg, 13)
+	if stop(segs, 0, Params{}) {
+		t.Fatalf("stop should continue when using default LeafMax with 13 segs")
+	}
+	if !stop(segs, 33, Params{}) {
+		t.Fatalf("stop should trigger when depth exceeds default MaxDepth")
+	}
+}
+
+func TestEvalCostSplitsAndBalance(t *testing.T) {
+	line := []geom.Seg{
+		{A: geom.V(-1, 1), B: geom.V(1, 1)},
+		{A: geom.V(-1, -1), B: geom.V(1, -1)},
+		{A: geom.V(-1, -1), B: geom.V(1, 1)},
+	}
+	p := Params{Alpha: 10, Beta: 2, Eps: geom.EPS}
+	splits, balance, cost := evalCost(line, geom.V(0, 0), geom.V(1, 0), p)
+	if splits != 1 {
+		t.Fatalf("splits=%d want 1", splits)
+	}
+	if balance != 0 {
+		t.Fatalf("balance=%d want 0", balance)
+	}
+	if cost != 10 {
+		t.Fatalf("cost=%v want 10", cost)
+	}
+}
+
+func TestSplitAllProducesFrontAndBack(t *testing.T) {
+	segs := []geom.Seg{{A: geom.V(-1, -1), B: geom.V(1, 1)}}
+	left, right, splits := splitAll(segs, geom.V(0, 0), geom.V(1, 0), Params{Eps: geom.EPS})
+	if splits != 1 {
+		t.Fatalf("splits=%d want 1", splits)
+	}
+	if len(left) != 1 || len(right) != 1 {
+		t.Fatalf("expected split into two segments, left=%d right=%d", len(left), len(right))
+	}
+	share := func(a, b geom.Vec) bool {
+		return math.Abs(a.X-b.X) < geom.EPS && math.Abs(a.Y-b.Y) < geom.EPS
+	}
+	if !share(left[0].A, right[0].B) && !share(left[0].B, right[0].A) {
+		t.Fatalf("split point mismatch")
+	}
+}
+
+func TestBuildRespectsLeafAndDepth(t *testing.T) {
+	segs := []geom.Seg{
+		{A: geom.V(-2, -2), B: geom.V(2, -2)},
+		{A: geom.V(2, -2), B: geom.V(2, 2)},
+		{A: geom.V(2, 2), B: geom.V(-2, 2)},
+		{A: geom.V(-2, 2), B: geom.V(-2, -2)},
+		{A: geom.V(-2, -2), B: geom.V(2, 2)},
+		{A: geom.V(-2, 2), B: geom.V(2, -2)},
+	}
+	p := Params{LeafMax: 2, MaxDepth: 3, Seed: 1, Cands: 4, Alpha: 5, Beta: 1, Eps: geom.EPS}
+	root := Build(segs, p)
+	if root == nil {
+		t.Fatalf("Build returned nil")
+	}
+
+	stats := Measure(root)
+	if stats.MaxDepth > p.MaxDepth {
+		t.Fatalf("MaxDepth=%d exceeds limit %d", stats.MaxDepth, p.MaxDepth)
+	}
+	if stats.Leaves == 0 {
+		t.Fatalf("expected some leaves in tree")
+	}
+	verifyLeaves(t, root, 0, p)
+}
+
+func verifyLeaves(t *testing.T, n *Node, depth int, p Params) {
+	t.Helper()
+	if n == nil {
+		return
+	}
+	if n.Leaf != nil {
+		if depth < p.MaxDepth && len(n.Leaf.Segs) > p.LeafMax {
+			t.Fatalf("leaf at depth %d has %d segs (limit %d)", depth, len(n.Leaf.Segs), p.LeafMax)
+		}
+		return
+	}
+	if depth >= p.MaxDepth {
+		t.Fatalf("internal node at depth %d exceeds MaxDepth %d", depth, p.MaxDepth)
+	}
+	verifyLeaves(t, n.Left, depth+1, p)
+	verifyLeaves(t, n.Right, depth+1, p)
+}