crc16: add tests (#3924)

Add tests to the crc16 package.

We don't have any. I was digging around in the code for some thing else and wanted to make a change to the crc logic and make sure I don't break it.

crc16/main_test.go

@@ -0,0 +1,20 @@
+package crc16
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestChecksum(t *testing.T) {
+	result := Checksum([]byte{0x12, 0x34, 0x56, 0x78, 0x90})
+	assert.Equal(t, []byte{0xe6, 0x48}, result)
+}
+
+func TestValidate(t *testing.T) {
+	err := Validate([]byte{0x12, 0x34, 0x56, 0x78, 0x90}, []byte{0xe6, 0x48})
+	assert.NoError(t, err)
+
+	err = Validate([]byte{0x12, 0x34, 0x56, 0x78, 0x90}, []byte{0xe7, 0x48})
+	assert.ErrorIs(t, err, ErrInvalidChecksum)
+}

go.list

@@ -72,8 +72,8 @@ github.com/spf13/viper v0.0.0-20150621231900-db7ff930a189
 github.com/stellar/go 
 github.com/stellar/go-xdr v0.0.0-20201028102745-f80a23dac78a
 github.com/stellar/throttled v2.2.3-0.20190823235211-89d75816f59d+incompatible
-github.com/stretchr/objx v0.1.1
-github.com/stretchr/testify v1.6.1
+github.com/stretchr/objx v0.3.0
+github.com/stretchr/testify v1.7.0
 github.com/tyler-smith/go-bip39 v0.0.0-20180618194314-52158e4697b8
 github.com/valyala/bytebufferpool v1.0.0
 github.com/valyala/fasthttp v0.0.0-20170109085056-0a7f0a797cd6

go.mod

@@ -62,7 +62,8 @@ require (
 	github.com/spf13/viper v0.0.0-20150621231900-db7ff930a189
 	github.com/stellar/go-xdr v0.0.0-20201028102745-f80a23dac78a
 	github.com/stellar/throttled v2.2.3-0.20190823235211-89d75816f59d+incompatible
-	github.com/stretchr/testify v1.6.1
+	github.com/stretchr/objx v0.3.0 // indirect
+	github.com/stretchr/testify v1.7.0
 	github.com/tyler-smith/go-bip39 v0.0.0-20180618194314-52158e4697b8
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasthttp v0.0.0-20170109085056-0a7f0a797cd6 // indirect

go.sum

@@ -323,13 +323,16 @@ github.com/stellar/go-xdr v0.0.0-20201028102745-f80a23dac78a/go.mod h1:yoxyU/M8n
 github.com/stellar/throttled v2.2.3-0.20190823235211-89d75816f59d+incompatible h1:jMXXAcz6xTarGDQ4VtVbtERogcmDQw4RaE85Cr9CgoQ=
 github.com/stellar/throttled v2.2.3-0.20190823235211-89d75816f59d+incompatible/go.mod h1:7CJ23pXirXBJq45DqvO6clzTEGM/l1SfKrgrzLry8b4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.1.1 h1:2vfRuCMp5sSVIDSqO8oNnWJq7mPa6KVP3iPIwFBuy8A=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.3.0 h1:NGXK3lHquSN08v5vWalVI/L8XU9hdzE/G6xsrze47As=
+github.com/stretchr/objx v0.3.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
-github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/tyler-smith/go-bip39 v0.0.0-20180618194314-52158e4697b8 h1:g3yQGZK+G6dfF/mw/SOwsTMzUVkpT4hB8pHxpbTXkKw=
 github.com/tyler-smith/go-bip39 v0.0.0-20180618194314-52158e4697b8/go.mod h1:sJ5fKU0s6JVwZjjcUEX2zFOnvq0ASQ2K9Zr6cf67kNs=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=