payload almost done

helper/test_helper.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/rsa"
 	"encoding/binary"
+	"encoding/json"
 	"io"
 	"math/big"
 	"math/rand"
@@ -14,11 +15,12 @@ func B(x int64) *big.Int {
 }
 
 type MockRandomReader struct {
-	random *rand.Rand
+	readLength int
+	random     *rand.Rand
 }
 
 func NewMockRandomReader() *MockRandomReader {
-	return &MockRandomReader{rand.New(rand.NewSource(99))}
+	return &MockRandomReader{0, rand.New(rand.NewSource(99))}
 }
 
 func (this *MockRandomReader) getNextFourRandomBytes() []byte {
@@ -31,9 +33,14 @@ func (this *MockRandomReader) Read(p []byte) (n int, err error) {
 	for i := 0; i < len(p); i += 4 {
 		copy(p[i:], this.getNextFourRandomBytes())
 	}
+	this.readLength += len(p)
 	return len(p), nil
 }
 
+func (this *MockRandomReader) GetReadLength() int {
+	return this.readLength
+}
+
 func (this *MockRandomReader) GetRandomBytes(size int) []byte {
 	ret := make([]byte, size)
 	this.Read(ret)
@@ -74,6 +81,17 @@ func (this *MockIoWriter) ReaderAt() io.ReaderAt {
 	return bytes.NewReader(this.state)
 }
 
+func (this *MockIoWriter) IsValidJson() bool {
+	m := make(map[string]interface{})
+	l := make([]interface{}, 0, 100)
+	if json.Unmarshal(this.Bytes(), &m) == nil {
+		return true
+	} else if json.Unmarshal(this.Bytes(), &l) == nil {
+		return true
+	}
+	return false
+}
+
 func Range(length int) []byte {
 	ret := make([]byte, length)
 	for i, _ := range ret {

helper/test_helper_test.go

@@ -43,6 +43,26 @@ func TestMockIoWriter(t *testing.T) {
 	}
 }
 
+func TestIsValidJson(t *testing.T) {
+	m := make(map[string]bool)
+	m[`{}`] = true
+	m[`[]`] = true
+	m[`[1, "abc", {"aa": true, "2": [1,2,3]}]`] = true
+	m[`{"aa": true, "2": [1,2,3]}`] = true
+
+	m[`regular string`] = false
+	m[`{"aa": true "2": [1,2,3]}`] = false // malformed json
+	for json_, isJSON := range m {
+		w := &MockIoWriter{[]byte(json_)}
+		ok := w.IsValidJson()
+		if ok && !isJSON {
+			t.Error(json_, "is not json but has been detected as json")
+		} else if !ok && isJSON {
+			t.Error(json_, "is json but has not been detected as json")
+		}
+	}
+}
+
 func TestGetRSAPublicKeyAndGetRSAPrivateKey(t *testing.T) {
 	privateKey := GetRSAPrivateKey(50)
 	if err := privateKey.Validate(); err != nil {
@@ -60,7 +80,7 @@ func TestGetRSAPublicKeyAndGetRSAPrivateKey(t *testing.T) {
 }
 
 func TestGetNextFourRandomBytes(t *testing.T) {
-	m := &MockRandomReader{rand.New(rand.NewSource(22))}
+	m := &MockRandomReader{0, rand.New(rand.NewSource(22))}
 	rb := m.getNextFourRandomBytes()
 	var expt []byte = []byte{233, 237, 107, 32}
 	if len(rb) != 4 {
@@ -103,3 +123,15 @@ func TestGetRandomBytes(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestGetReadLength(t *testing.T) {
+	m := NewMockRandomReader()
+	dump := make([]byte, 4*10+3)
+	if _, err := m.Read(dump); err != nil {
+		t.Error(err)
+		return
+	}
+	if m.GetReadLength() != 4*10+3 {
+		t.Error("bad read length")
+	}
+}