Fix unit test, it should return after any error is returned from Decode

function whether expected or not, rather than continue and try to
compare invalid decoded results.

Extend the unit test slightly to check the header.

Remove go-test/deep dependency in favour of standard library reflect
package.

function_call.go

@@ -6,7 +6,7 @@ import (
 	"github.com/jackc/pgio"
 )
 
-type FunctionCall struct{
+type FunctionCall struct {
 	Function         uint32
 	ArgFormatCodes   []uint16
 	Arguments        [][]byte
@@ -55,7 +55,7 @@ func (dst *FunctionCall) Decode(src []byte) error {
 			arguments[i] = nil
 		} else {
 			// The value of the argument, in the format indicated by the associated format code. n is the above length.
-			argumentValue := src[rp:rp+argumentLength]
+			argumentValue := src[rp : rp+argumentLength]
 			rp += argumentLength
 			arguments[i] = argumentValue
 		}

function_call_test.go

@@ -1,7 +1,8 @@
 package pgproto3
 
 import (
-	"github.com/go-test/deep"
+	"encoding/binary"
+	"reflect"
 	"testing"
 )
 
@@ -17,7 +18,7 @@ func TestFunctionCall_EncodeDecode(t *testing.T) {
 		fields  fields
 		wantErr bool
 	}{
-		{"foo", fields{uint32(123), []uint16{0, 1, 0, 1}, [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}, uint16(0)}, false},
+		{"valid", fields{uint32(123), []uint16{0, 1, 0, 1}, [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}, uint16(1)}, false},
 		{"invalid format code", fields{uint32(123), []uint16{2, 1, 0, 1}, [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}, uint16(0)}, true},
 		{"invalid result format code", fields{uint32(123), []uint16{1, 1, 0, 1}, [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}, uint16(2)}, true},
 	}
@@ -30,14 +31,31 @@ func TestFunctionCall_EncodeDecode(t *testing.T) {
 				ResultFormatCode: tt.fields.ResultFormatCode,
 			}
 			encoded := src.Encode([]byte{})
-			decoded := &FunctionCall{}
+			dst := &FunctionCall{}
-			err := decoded.Decode(encoded[5:])
+			// Check the header
-			if (err != nil) != tt.wantErr {
+			msgTypeCode := encoded[0]
-                t.Errorf("FunctionCall.Decode() error = %v, wantErr %v", err, tt.wantErr)
+			if msgTypeCode != 'F' {
+				t.Errorf("msgTypeCode %v should be 'F'", msgTypeCode)
 				return
 			}
-			if diff := deep.Equal(src, decoded); diff != nil {
+			// Check length, does not include type code character
-				t.Error(diff)
+			l := binary.BigEndian.Uint32(encoded[1:5])
+			if int(l) != (len(encoded) - 1) {
+				t.Errorf("Incorrect message length, got = %v, wanted = %v", l, len(encoded))
+			}
+			// Check decoding works as expected
+			err := dst.Decode(encoded[5:])
+			if err != nil {
+				if !tt.wantErr {
+					t.Errorf("FunctionCall.Decode() error = %v, wantErr %v", err, tt.wantErr)
+				}
+				return
+			}
+
+			if !reflect.DeepEqual(src, dst) {
+				t.Error("difference after encode / decode cycle")
+				t.Errorf("src = %v", src)
+				t.Errorf("dst = %v", dst)
 			}
 		})
 	}

go.mod

@@ -3,7 +3,6 @@ module github.com/jackc/pgproto3/v2
 go 1.12
 
 require (
-	github.com/go-test/deep v1.0.8
 	github.com/jackc/chunkreader/v2 v2.0.0
 	github.com/jackc/pgio v1.0.0
 	github.com/stretchr/testify v1.4.0

go.sum

@@ -1,7 +1,5 @@
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-test/deep v1.0.8 h1:TDsG77qcSprGbC6vTN8OuXp5g+J+b5Pcguhf7Zt61VM=
-github.com/go-test/deep v1.0.8/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
 github.com/jackc/chunkreader/v2 v2.0.0 h1:DUwgMQuuPnS0rhMXenUtZpqZqrR/30NWY+qQvTpSvEs=
 github.com/jackc/chunkreader/v2 v2.0.0/go.mod h1:odVSm741yZoC3dpHEUXIqA9tQRhFrgOHwnPIn9lDKlk=
 github.com/jackc/pgio v1.0.0 h1:g12B9UwVnzGhueNavwioyEEpAmqMe1E/BN9ES+8ovkE=
@@ -11,7 +9,6 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=