finish DecodeLen & len unit test

len_test.go

@@ -0,0 +1,15 @@
+package unibase2n
+
+import "testing"
+
+func TestEnDecodeLen(t *testing.T) {
+	bs := Base{bit: 1}
+	for ; bs.bit < 16; bs.bit++ {
+		for i := 1; i <= 65536; i++ {
+			in := bs.DecodeLen(bs.EncodeLen(i))
+			if i != in {
+				t.Fatal("bit:", bs.bit, "in:", i, "!= out:", in)
+			}
+		}
+	}
+}