From b7840aa9cbae97c21cfc1ec69fd085729714f4ea Mon Sep 17 00:00:00 2001
From: saji <champ189@umn.edu>
Date: Thu, 4 May 2023 14:05:37 -0500
Subject: [PATCH] atcmdresponse parsing fixes and tests

---
 internal/xbee/at.go      | 12 ++++++------
 internal/xbee/at_test.go | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/internal/xbee/at.go b/internal/xbee/at.go
index 09f1cdc..b2fb529 100644
--- a/internal/xbee/at.go
+++ b/internal/xbee/at.go
@@ -3,7 +3,7 @@ package xbee
 import (
 	"bytes"
 	"encoding/binary"
-	"fmt"
+	"errors"
 )
 
 // This code is handled slightly differently. Rather than use structs to represent
@@ -13,7 +13,6 @@ import (
 // The downside is that it's more difficult to deal with.
 //
 // AT command responses are handled with a struct to get the response status code.
-//
 
 // an ATCmd is anything that has a Payload function that returns the given payload
 // pre-formatted to be send over the wire, and a Cmd command that returns the 2-character
@@ -70,15 +69,16 @@ type ATCmdResponse struct {
 func ParseATCmdResponse(p []byte) (*ATCmdResponse, error) {
 
 	if p[0] != 0x88 {
-		return nil, fmt.Errorf("invalid frame type 0x%x", p[0])
+		return nil, errors.New("not an AT command response")
+	}
+	if len(p) < 5 {
+		return nil, errors.New("received partial AT command response")
 	}
 	resp := &ATCmdResponse{
 		Cmd:    string(p[2:4]),
 		Status: ATCmdStatus(p[4]),
-		// TODO: check if this overflows when there's no payload.
-		Data: p[5:],
+		Data:   p[5:],
 	}
-
 	return resp, nil
 }
 
diff --git a/internal/xbee/at_test.go b/internal/xbee/at_test.go
index 269e30f..611e41c 100644
--- a/internal/xbee/at_test.go
+++ b/internal/xbee/at_test.go
@@ -15,7 +15,41 @@ func TestParseATCmdResponse(t *testing.T) {
 		want    *ATCmdResponse
 		wantErr bool
 	}{
-		// TODO: Add test cases.
+		{
+			name: "AT Command Change OK",
+			args: args{
+				p: []byte{0x88, 0x53, 0x49, 0x44, 0x00},
+			},
+			want: &ATCmdResponse{
+				Cmd:    "ID",
+				Data:   []byte{},
+				Status: ATCmdStatusOK,
+			},
+			wantErr: false,
+		},
+		{
+			name: "AT Command Query OK",
+			args: args{
+				p: []byte{0x88, 0x53, 0x49, 0x44, 0x00, 0x43, 0xEF},
+			},
+			want: &ATCmdResponse{
+				Cmd:    "ID",
+				Data:   []byte{0x43, 0xEF},
+				Status: ATCmdStatusOK,
+			},
+		},
+		{
+			name: "AT Command Parameter Error",
+			args: args{
+				p: []byte{0x88, 0x53, 0x49, 0x44, 0x03},
+			},
+			want: &ATCmdResponse{
+				Cmd:    "ID",
+				Data:   []byte{},
+				Status: ATCmdStatusInvalidParam,
+			},
+			wantErr: false,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {