1 files changed, 172 insertions, 0 deletions
diff --git a/tests/rlp_test_util.go b/tests/rlp_test_util.go
new file mode 100644
index 000000000..c322b78c6
--- /dev/null
+++ b/tests/rlp_test_util.go
@@ -0,0 +1,172 @@
+package tests
+
+import (
+	"bytes"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"math/big"
+	"os"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+// RLPTest is the JSON structure of a single RLP test.
+type RLPTest struct {
+	// If the value of In is "INVALID" or "VALID", the test
+	// checks whether Out can be decoded into a value of
+	// type interface{}.
+	//
+	// For other JSON values, In is treated as a driver for
+	// calls to rlp.Stream. The test also verifies that encoding
+	// In produces the bytes in Out.
+	In interface{}
+
+	// Out is a hex-encoded RLP value.
+	Out string
+}
+
+// RunRLPTest runs the tests in the given file, skipping tests by name.
+func RunRLPTest(file string, skip []string) error {
+	f, err := os.Open(file)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	return RunRLPTestWithReader(f, skip)
+}
+
+// RunRLPTest runs the tests encoded in r, skipping tests by name.
+func RunRLPTestWithReader(r io.Reader, skip []string) error {
+	var tests map[string]*RLPTest
+	if err := readJson(r, &tests); err != nil {
+		return err
+	}
+	for _, s := range skip {
+		delete(tests, s)
+	}
+	for name, test := range tests {
+		if err := test.Run(); err != nil {
+			return fmt.Errorf("test %q failed: %v", name, err)
+		}
+	}
+	return nil
+}
+
+// Run executes the test.
+func (t *RLPTest) Run() error {
+	outb, err := hex.DecodeString(t.Out)
+	if err != nil {
+		return fmt.Errorf("invalid hex in Out")
+	}
+
+	// Handle simple decoding tests with no actual In value.
+	if t.In == "VALID" || t.In == "INVALID" {
+		return checkDecodeInterface(outb, t.In == "VALID")
+	}
+
+	// Check whether encoding the value produces the same bytes.
+	in := translateJSON(t.In)
+	b, err := rlp.EncodeToBytes(in)
+	if err != nil {
+		return fmt.Errorf("encode failed: %v", err)
+	}
+	if !bytes.Equal(b, outb) {
+		return fmt.Errorf("encode produced %x, want %x", b, outb)
+	}
+	// Test stream decoding.
+	s := rlp.NewStream(bytes.NewReader(outb), 0)
+	return checkDecodeFromJSON(s, in)
+}
+
+func checkDecodeInterface(b []byte, isValid bool) error {
+	err := rlp.DecodeBytes(b, new(interface{}))
+	switch {
+	case isValid && err != nil:
+		return fmt.Errorf("decoding failed: %v", err)
+	case !isValid && err == nil:
+		return fmt.Errorf("decoding of invalid value succeeded")
+	}
+	return nil
+}
+
+// translateJSON makes test json values encodable with RLP.
+func translateJSON(v interface{}) interface{} {
+	switch v := v.(type) {
+	case float64:
+		return uint64(v)
+	case string:
+		if len(v) > 0 && v[0] == '#' { // # starts a faux big int.
+			big, ok := new(big.Int).SetString(v[1:], 10)
+			if !ok {
+				panic(fmt.Errorf("bad test: bad big int: %q", v))
+			}
+			return big
+		}
+		return []byte(v)
+	case []interface{}:
+		new := make([]interface{}, len(v))
+		for i := range v {
+			new[i] = translateJSON(v[i])
+		}
+		return new
+	default:
+		panic(fmt.Errorf("can't handle %T", v))
+	}
+}
+
+// checkDecodeFromJSON decodes from s guided by exp. exp drives the
+// Stream by invoking decoding operations (Uint, Big, List, ...) based
+// on the type of each value. The value decoded from the RLP stream
+// must match the JSON value.
+func checkDecodeFromJSON(s *rlp.Stream, exp interface{}) error {
+	switch exp := exp.(type) {
+	case uint64:
+		i, err := s.Uint()
+		if err != nil {
+			return addStack("Uint", exp, err)
+		}
+		if i != exp {
+			return addStack("Uint", exp, fmt.Errorf("result mismatch: got %d", i))
+		}
+	case *big.Int:
+		big := new(big.Int)
+		if err := s.Decode(&big); err != nil {
+			return addStack("Big", exp, err)
+		}
+		if big.Cmp(exp) != 0 {
+			return addStack("Big", exp, fmt.Errorf("result mismatch: got %d", big))
+		}
+	case []byte:
+		b, err := s.Bytes()
+		if err != nil {
+			return addStack("Bytes", exp, err)
+		}
+		if !bytes.Equal(b, exp) {
+			return addStack("Bytes", exp, fmt.Errorf("result mismatch: got %x", b))
+		}
+	case []interface{}:
+		if _, err := s.List(); err != nil {
+			return addStack("List", exp, err)
+		}
+		for i, v := range exp {
+			if err := checkDecodeFromJSON(s, v); err != nil {
+				return addStack(fmt.Sprintf("[%d]", i), exp, err)
+			}
+		}
+		if err := s.ListEnd(); err != nil {
+			return addStack("ListEnd", exp, err)
+		}
+	default:
+		panic(fmt.Errorf("unhandled type: %T", exp))
+	}
+	return nil
+}
+
+func addStack(op string, val interface{}, err error) error {
+	lines := strings.Split(err.Error(), "\n")
+	lines = append(lines, fmt.Sprintf("\t%s: %v", op, val))
+	return errors.New(strings.Join(lines, "\n"))
+}