v0.1.3 ANSI 16 indices and RGB to 16

xterm_test.go

@@ -0,0 +1,18 @@
+package color
+
+import "testing"
+
+// Each reference shade maps to its own index, so the constants, the table and
+// the search agree; the named primaries land on the bright indices like xterm.
+func TestRGBTo16MapsReferenceShadesToTheirIndex(t *testing.T) {
+	for i, c := range ansi16 {
+		if got := RGBTo16(c); got != uint8(i) {
+			t.Errorf("shade %d %s: index %d", i, c.Hex(), got)
+		}
+	}
+	for c, want := range map[RGB]uint8{Red: ANSIBrightRed, Black: ANSIBlack, White: ANSIBrightWhite, {170, 0, 0}: ANSIRed} {
+		if got := RGBTo16(c); got != want {
+			t.Errorf("%s: index %d, want %d", c.Hex(), got, want)
+		}
+	}
+}