test: 补全单元测试

protocol/mc_test.go

@@ -0,0 +1,105 @@
+package protocol
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestGetMcHost(t *testing.T) {
+	tests := []struct {
+		name string
+		buf  []byte
+		want string
+	}{
+		{
+			name: "short packet",
+			buf:  []byte{0x01, 0x02, 0x03, 0x04},
+			want: "",
+		},
+		{
+			name: "host length exceeds packet",
+			buf:  []byte{0x01, 0x02, 0x03, 0x04, 0x05, 'a'},
+			want: "",
+		},
+		{
+			name: "plain host",
+			buf:  mcTestPacket("play.example", 0x63, 0x00),
+			want: "play.example",
+		},
+		{
+			name: "host with null suffix",
+			buf:  mcTestPacket("play.example\x00FML\x00", 0x63, 0x00),
+			want: "play.example",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := GetMcHost(tt.buf); got != tt.want {
+				t.Fatalf("GetMcHost() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestReplaceMcHost(t *testing.T) {
+	tests := []struct {
+		name string
+		buf  []byte
+		host string
+		want []byte
+	}{
+		{
+			name: "short packet",
+			buf:  []byte{0x01, 0x02, 0x03, 0x04},
+			host: "new.example",
+			want: nil,
+		},
+		{
+			name: "host length exceeds packet",
+			buf:  []byte{0x01, 0x02, 0x03, 0x04, 0x05, 'a'},
+			host: "new.example",
+			want: nil,
+		},
+		{
+			name: "replace plain host",
+			buf:  mcTestPacket("old.example", 0x63, 0x00),
+			host: "new.example",
+			want: mcTestPacket("new.example", 0x63, 0x00),
+		},
+		{
+			name: "preserve null suffix",
+			buf:  mcTestPacket("old.example\x00FML\x00", 0x63, 0x00),
+			host: "new.example",
+			want: mcTestPacket("new.example\x00FML\x00", 0x63, 0x00),
+		},
+		{
+			name: "replace with shorter host",
+			buf:  mcTestPacket("long.example", 0x01, 0x02, 0x03),
+			host: "x",
+			want: mcTestPacket("x", 0x01, 0x02, 0x03),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ReplaceMcHost(append([]byte(nil), tt.buf...), tt.host)
+			if !bytes.Equal(got, tt.want) {
+				t.Fatalf("ReplaceMcHost() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func mcTestPacket(host string, tail ...byte) []byte {
+	packet := []byte{
+		byte(4 + 1 + len(host) + len(tail)),
+		0x00,
+		0x00,
+		0x00,
+		byte(len(host)),
+	}
+	packet = append(packet, host...)
+	packet = append(packet, tail...)
+	return packet
+}