diff --git a/codec/h264/h264dec/nalunit_test.go b/codec/h264/h264dec/nalunit_test.go
index 2519fafa..f3828880 100644
--- a/codec/h264/h264dec/nalunit_test.go
+++ b/codec/h264/h264dec/nalunit_test.go
@@ -50,3 +50,44 @@ func TestNewMVCExtension(t *testing.T) {
 		}
 	}
 }
+
+func TestNewThreeDAVCExtension(t *testing.T) {
+	tests := []struct {
+		in   string
+		want ThreeDAVCExtension
+		err  error
+	}{
+		{
+			in: "0001 0000" + // u(8) view_idx = 16
+				"1" + // u(1) depth_flag = true
+				"0" + // u(1) non_idr_flag = false
+				"010" + // u(1) temporal_id = 2
+				"1" + // u(1) anchor_pic_flag = true
+				"1", // u(1) inter_view_flag = true
+			want: ThreeDAVCExtension{
+				ViewIdx:       16,
+				DepthFlag:     true,
+				NonIdrFlag:    false,
+				TemporalID:    2,
+				AnchorPicFlag: true,
+				InterViewFlag: true,
+			},
+		},
+	}
+
+	for i, test := range tests {
+		inBytes, err := binToSlice(test.in)
+		if err != nil {
+			t.Fatalf("did not expect error %v from binToSlice for test %d", err, i)
+		}
+
+		got, err := NewThreeDAVCExtension(bits.NewBitReader(bytes.NewReader(inBytes)))
+		if err != test.err {
+			t.Errorf("did not get expected error for test %d\nGot: %v\nWant: %v\n", i, err, test.err)
+		}
+
+		if !reflect.DeepEqual(*got, test.want) {
+			t.Errorf("did not get expected result for test %d\nGot: %v\nWant: %v\n", i, *got, test.want)
+		}
+	}
+}