accounts: address comments and add tests

accounts/abi/argument.go

@@ -91,7 +91,7 @@ func (arguments Arguments) isTuple() bool {
 func (arguments Arguments) Unpack(v interface{}, data []byte) error {
 	if len(data) == 0 {
 		if len(arguments) != 0 {
-			return fmt.Errorf("abi: unmarshalling empty output")
+			return fmt.Errorf("abi: attempting to unmarshall an empty string while arguments are expected")
 		} else {
 			return nil // Nothing to unmarshal, return
 		}
@@ -114,7 +114,7 @@ func (arguments Arguments) Unpack(v interface{}, data []byte) error {
 func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte) error {
 	if len(data) == 0 {
 		if len(arguments) != 0 {
-			return fmt.Errorf("abi: unmarshalling empty output")
+			return fmt.Errorf("abi: attempting to unmarshall an empty string while arguments are expected")
 		} else {
 			return nil // Nothing to unmarshal, return
 		}

accounts/abi/bind/bind.go

@@ -342,7 +342,7 @@ func bindTopicTypeGo(kind abi.Type, structs map[string]*tmplStruct) string {
 	// parameters that are not value types i.e. arrays and structs are not
 	// stored directly but instead a keccak256-hash of an encoding is stored.
 	//
-	// We only only convert string and bytes to hash, still need to deal with
+	// We only convert stringS and bytes to hash, still need to deal with
 	// array(both fixed-size and dynamic-size) and struct.
 	if bound == "string" || bound == "[]byte" {
 		bound = "common.Hash"
@@ -359,7 +359,7 @@ func bindTopicTypeJava(kind abi.Type, structs map[string]*tmplStruct) string {
 	// parameters that are not value types i.e. arrays and structs are not
 	// stored directly but instead a keccak256-hash of an encoding is stored.
 	//
-	// We only only convert string and bytes to hash, still need to deal with
+	// We only convert stringS and bytes to hash, still need to deal with
 	// array(both fixed-size and dynamic-size) and struct.
 	if bound == "String" || bound == "byte[]" {
 		bound = "Hash"
@@ -380,7 +380,7 @@ var bindStructType = map[Lang]func(kind abi.Type, structs map[string]*tmplStruct
 func bindStructTypeGo(kind abi.Type, structs map[string]*tmplStruct) string {
 	switch kind.T {
 	case abi.TupleTy:
-		// We composite raw struct name and canonical parameter expression
+		// We compose raw struct name and canonical parameter expression
 		// together here. The reason is before solidity v0.5.11, kind.TupleRawName
 		// is empty, so we use canonical parameter expression to distinguish
 		// different struct definition. From the consideration of backward
@@ -419,7 +419,7 @@ func bindStructTypeGo(kind abi.Type, structs map[string]*tmplStruct) string {
 func bindStructTypeJava(kind abi.Type, structs map[string]*tmplStruct) string {
 	switch kind.T {
 	case abi.TupleTy:
-		// We composite raw struct name and canonical parameter expression
+		// We compose raw struct name and canonical parameter expression
 		// together here. The reason is before solidity v0.5.11, kind.TupleRawName
 		// is empty, so we use canonical parameter expression to distinguish
 		// different struct definition. From the consideration of backward

accounts/abi/bind/topics.go

@@ -84,7 +84,7 @@ func makeTopics(query ...[]interface{}) ([][]common.Hash, error) {
 				// parameters that are not value types i.e. arrays and structs are not
 				// stored directly but instead a keccak256-hash of an encoding is stored.
 				//
-				// We only only convert string and bytes to hash, still need to deal with
+				// We only convert stringS and bytes to hash, still need to deal with
 				// array(both fixed-size and dynamic-size) and struct.
 
 				// Attempt to generate the topic from funky types

accounts/abi/unpack_test.go

@@ -51,6 +51,7 @@ func (test unpackTest) checkError(err error) error {
 }
 
 var unpackTests = []unpackTest{
+	// Bools
 	{
 		def:  `[{ "type": "bool" }]`,
 		enc:  "0000000000000000000000000000000000000000000000000000000000000001",
@@ -73,6 +74,7 @@ var unpackTests = []unpackTest{
 		want: false,
 		err:  "abi: improperly encoded boolean value",
 	},
+	// Integers
 	{
 		def:  `[{"type": "uint32"}]`,
 		enc:  "0000000000000000000000000000000000000000000000000000000000000001",
@@ -122,11 +124,13 @@ var unpackTests = []unpackTest{
 		enc:  "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
 		want: big.NewInt(-1),
 	},
+	// Address
 	{
 		def:  `[{"type": "address"}]`,
 		enc:  "0000000000000000000000000100000000000000000000000000000000000000",
 		want: common.Address{1},
 	},
+	// Bytes
 	{
 		def:  `[{"type": "bytes32"}]`,
 		enc:  "0100000000000000000000000000000000000000000000000000000000000000",
@@ -154,23 +158,39 @@ var unpackTests = []unpackTest{
 		enc:  "0100000000000000000000000000000000000000000000000000000000000000",
 		want: [32]byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
 	},
+	// Functions
 	{
 		def:  `[{"type": "function"}]`,
 		enc:  "0100000000000000000000000000000000000000000000000000000000000000",
 		want: [24]byte{1},
 	},
-	// slices
+	// Slice and Array
 	{
 		def:  `[{"type": "uint8[]"}]`,
 		enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
 		want: []uint8{1, 2},
 	},
+	{
+		def:  `[{"type": "uint8[]"}]`,
+		enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000",
+		want: []uint8{},
+	},
+	{
+		def:  `[{"type": "uint256[]"}]`,
+		enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000",
+		want: []*big.Int{},
+	},
 	{
 		def:  `[{"type": "uint8[2]"}]`,
 		enc:  "00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
 		want: [2]uint8{1, 2},
 	},
 	// multi dimensional, if these pass, all types that don't require length prefix should pass
+	{
+		def:  `[{"type": "uint8[][]"}]`,
+		enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000",
+		want: [][]uint8{},
+	},
 	{
 		def:  `[{"type": "uint8[][]"}]`,
 		enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000a0000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
@@ -186,11 +206,21 @@ var unpackTests = []unpackTest{
 		enc:  "0000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
 		want: [2][2]uint8{{1, 2}, {1, 2}},
 	},
+	{
+		def:  `[{"type": "uint8[][2]"}]`,
+		enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000006000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+		want: [2][]uint8{{}, {}},
+	},
 	{
 		def:  `[{"type": "uint8[][2]"}]`,
 		enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001",
 		want: [2][]uint8{{1}, {1}},
 	},
+	{
+		def:  `[{"type": "uint8[2][]"}]`,
+		enc:  "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000",
+		want: [][2]uint8{},
+	},
 	{
 		def:  `[{"type": "uint8[2][]"}]`,
 		enc:  "0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002",
@@ -420,7 +450,7 @@ func TestUnpack(t *testing.T) {
 			}
 			encb, err := hex.DecodeString(test.enc)
 			if err != nil {
-				t.Fatalf("invalid hex: %s" + test.enc)
+				t.Fatalf("invalid hex %s: %v", test.enc, err)
 			}
 			outptr := reflect.New(reflect.TypeOf(test.want))
 			err = abi.Unpack(outptr.Interface(), "method", encb)