diff --git a/pkg/app2/hsframe_test.go b/pkg/app2/hsframe_test.go
new file mode 100644
index 000000000..ab66e376f
--- /dev/null
+++ b/pkg/app2/hsframe_test.go
@@ -0,0 +1,69 @@
+package app2
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestHSFrame(t *testing.T) {
+	t.Run("ok", func(t *testing.T) {
+		body := struct {
+			Test string `json:"test"`
+		}{
+			Test: "some string",
+		}
+
+		bodyBytes, err := json.Marshal(body)
+		require.NoError(t, err)
+
+		procID := ProcID(1)
+		frameType := HSFrameTypeDMSGListen
+		bodyLen := len(bodyBytes)
+
+		hsFrame, err := NewHSFrame(procID, frameType, body)
+		require.NoError(t, err)
+
+		require.Equal(t, len(hsFrame), HSFrameHeaderLen+len(bodyBytes))
+
+		gotProcID := ProcID(binary.BigEndian.Uint16(hsFrame))
+		require.Equal(t, gotProcID, procID)
+
+		gotFrameType := HSFrameType(hsFrame[HSFrameProcIDLen])
+		require.Equal(t, gotFrameType, frameType)
+
+		gotBodyLen := int(binary.BigEndian.Uint16(hsFrame[HSFrameProcIDLen+HSFrameTypeLen:]))
+		require.Equal(t, gotBodyLen, bodyLen)
+
+		require.Equal(t, bodyBytes, []byte(hsFrame[HSFrameProcIDLen+HSFrameTypeLen+HSFrameBodyLenLen:]))
+
+		gotProcID = hsFrame.ProcID()
+		require.Equal(t, gotProcID, procID)
+
+		gotFrameType = hsFrame.FrameType()
+		require.Equal(t, gotFrameType, frameType)
+
+		gotBodyLen = hsFrame.BodyLen()
+		require.Equal(t, gotBodyLen, bodyLen)
+	})
+
+	t.Run("fail - too large body", func(t *testing.T) {
+		body := struct {
+			Test string `json:"test"`
+		}{
+			Test: "some string",
+		}
+
+		for len(body.Test) <= HSFrameMaxBodyLen {
+			body.Test += body.Test
+		}
+
+		procID := ProcID(1)
+		frameType := HSFrameTypeDMSGListen
+
+		_, err := NewHSFrame(procID, frameType, body)
+		require.Equal(t, err, ErrHSFrameBodyTooLarge)
+	})
+}