Add icon: Lucide 1.58.0 SVG set, lazy parse, Must, Names

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

icon/icon_test.go

@@ -0,0 +1,64 @@
+package icon
+
+import (
+	"slices"
+	"testing"
+
+	"github.com/egoist/mygo/ui"
+)
+
+func TestEveryIconParses(t *testing.T) {
+	n := Names()
+	if len(n) != 2159 {
+		t.Fatalf("icons = %d, want 2159", len(n))
+	}
+	if !slices.IsSorted(n) {
+		t.Error("Names not sorted")
+	}
+	for _, name := range n {
+		if Must(name) == nil {
+			t.Errorf("%s parsed to nil", name)
+		}
+	}
+}
+
+func TestMustCaches(t *testing.T) {
+	if Must("check") != Must("check") {
+		t.Error("Must parsed check twice")
+	}
+}
+
+func TestMustPanicsOnUnknown(t *testing.T) {
+	defer func() {
+		if recover() == nil {
+			t.Error("Must(nope) did not panic")
+		}
+	}()
+	Must("nope")
+}
+
+func TestNamesIsACopy(t *testing.T) {
+	n := Names()
+	n[0] = "changed"
+	if Names()[0] == "changed" {
+		t.Error("Names exposed its slice")
+	}
+}
+
+func TestIconDraws(t *testing.T) {
+	img := ui.Render(func(c *ui.Context) {
+		ui.Icon(c, Must("check")).Size(24, 24)
+	}, 32, 32, 1)
+	bg := img.RGBAAt(0, 0)
+	inked := 0
+	for y := range 32 {
+		for x := range 32 {
+			if img.RGBAAt(x, y) != bg {
+				inked++
+			}
+		}
+	}
+	if inked < 20 {
+		t.Errorf("check drew %d pixels", inked)
+	}
+}