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

@@ -6,10 +6,10 @@ import (
 	"github.com/jackc/pgio"
 )
 
-type FunctionCall struct{
-	Function uint32
-	ArgFormatCodes []uint16
-	Arguments [][]byte
+type FunctionCall struct {
+	Function         uint32
+	ArgFormatCodes   []uint16
+	Arguments        [][]byte
 	ResultFormatCode uint16
 }
 
@@ -24,9 +24,9 @@ func (dst *FunctionCall) Decode(src []byte) error {
 	// Specifies the object ID of the function to call.
 	dst.Function = binary.BigEndian.Uint32(src[rp:])
 	rp += 4
-	// The number of argument format codes that follow (denoted C below). 
-	// This can be zero to indicate that there are no arguments or that the arguments all use the default format (text); 
-	// or one, in which case the specified format code is applied to all arguments; 
+	// The number of argument format codes that follow (denoted C below).
+	// This can be zero to indicate that there are no arguments or that the arguments all use the default format (text);
+	// or one, in which case the specified format code is applied to all arguments;
 	// or it can equal the actual number of arguments.
 	nArgumentCodes := int(binary.BigEndian.Uint16(src[rp:]))
 	rp += 2
@@ -37,36 +37,36 @@ func (dst *FunctionCall) Decode(src []byte) error {
 		if ac != 0 && ac != 1 {
 			return &invalidMessageFormatErr{messageType: "FunctionCall"}
 		}
-        argumentCodes[i] = ac
-        rp += 2
-    }
+		argumentCodes[i] = ac
+		rp += 2
+	}
 	dst.ArgFormatCodes = argumentCodes
-	
+
 	// Specifies the number of arguments being supplied to the function.
 	nArguments := int(binary.BigEndian.Uint16(src[rp:]))
 	rp += 2
 	arguments := make([][]byte, nArguments)
 	for i := 0; i < nArguments; i++ {
-		// The length of the argument value, in bytes (this count does not include itself). Can be zero. 
+		// The length of the argument value, in bytes (this count does not include itself). Can be zero.
 		// As a special case, -1 indicates a NULL argument value. No value bytes follow in the NULL case.
-        argumentLength := int(binary.BigEndian.Uint32(src[rp:]))
-        rp += 4
-        if argumentLength == -1 {
+		argumentLength := int(binary.BigEndian.Uint32(src[rp:]))
+		rp += 4
+		if argumentLength == -1 {
 			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
-        }
-    }
+		}
+	}
 	dst.Arguments = arguments
 	// The format code for the function result. Must presently be zero (text) or one (binary).
 	resultFormatCode := binary.BigEndian.Uint16(src[rp:])
 	if resultFormatCode != 0 && resultFormatCode != 1 {
-        return &invalidMessageFormatErr{messageType: "FunctionCall"}
-    }
-	dst.ResultFormatCode  = resultFormatCode
+		return &invalidMessageFormatErr{messageType: "FunctionCall"}
+	}
+	dst.ResultFormatCode = resultFormatCode
 	return nil
 }
 
@@ -78,17 +78,17 @@ func (src *FunctionCall) Encode(dst []byte) []byte {
 	dst = pgio.AppendUint32(dst, src.Function)
 	dst = pgio.AppendUint16(dst, uint16(len(src.ArgFormatCodes)))
 	for _, argFormatCode := range src.ArgFormatCodes {
-        dst = pgio.AppendUint16(dst, argFormatCode)
-    }
+		dst = pgio.AppendUint16(dst, argFormatCode)
+	}
 	dst = pgio.AppendUint16(dst, uint16(len(src.Arguments)))
 	for _, argument := range src.Arguments {
-        if argument == nil {
-            dst = pgio.AppendInt32(dst, -1)
-        } else {
-            dst = pgio.AppendInt32(dst, int32(len(argument)))
-            dst = append(dst, argument...)
-        }
-    }
+		if argument == nil {
+			dst = pgio.AppendInt32(dst, -1)
+		} else {
+			dst = pgio.AppendInt32(dst, int32(len(argument)))
+			dst = append(dst, argument...)
+		}
+	}
 	dst = pgio.AppendUint16(dst, src.ResultFormatCode)
 	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 	return dst

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},
 	}
@@ -30,15 +31,32 @@ func TestFunctionCall_EncodeDecode(t *testing.T) {
 				ResultFormatCode: tt.fields.ResultFormatCode,
 			}
 			encoded := src.Encode([]byte{})
-			decoded := &FunctionCall{}
-			err := decoded.Decode(encoded[5:])
-			if (err != nil) != tt.wantErr {
-                t.Errorf("FunctionCall.Decode() error = %v, wantErr %v", err, tt.wantErr)
-                return
-            }
-			if diff := deep.Equal(src, decoded); diff != nil {
-				t.Error(diff)
+			dst := &FunctionCall{}
+			// Check the header
+			msgTypeCode := encoded[0]
+			if msgTypeCode != 'F' {
+				t.Errorf("msgTypeCode %v should be 'F'", msgTypeCode)
+				return
+			}
+			// Check length, does not include type code character
+			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=