diff --git a/builtin/assertion.go b/builtin/assertion.go
index 30ecfdd5..31110221 100644
--- a/builtin/assertion.go
+++ b/builtin/assertion.go
@@ -49,8 +49,37 @@ func EndsWith(t assert.TestingT, expected, actual interface{}, msgAndArgs ...int
 }
 
 func EqualLength(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool {
-	if !assert.IsType(t, 129, expected, fmt.Sprintf("expected type is not int, got %#v", expected)) {
-		return false
+	length, err := convertInt(expected)
+	if err != nil {
+		return assert.Fail(t, fmt.Sprintf("expected type is not int, got %#v", expected), msgAndArgs...)
+	}
+
+	return assert.Len(t, actual, length, msgAndArgs...)
+}
+
+func convertInt(value interface{}) (int, error) {
+	switch v := value.(type) {
+	case int:
+		return v, nil
+	case int8:
+		return int(v), nil
+	case int16:
+		return int(v), nil
+	case int32:
+		return int(v), nil
+	case int64:
+		return int(v), nil
+	case uint:
+		return int(v), nil
+	case uint8:
+		return int(v), nil
+	case uint16:
+		return int(v), nil
+	case uint32:
+		return int(v), nil
+	case uint64:
+		return int(v), nil
+	default:
+		return 0, fmt.Errorf("unsupported int convertion for %v(%T)", v, v)
 	}
-	return assert.Len(t, actual, expected.(int), msgAndArgs...)
 }
diff --git a/convert.go b/convert.go
index 66cfd343..80280226 100644
--- a/convert.go
+++ b/convert.go
@@ -80,7 +80,9 @@ func loadFromJSON(path string) (*TCase, error) {
 	}
 
 	tc := &TCase{}
-	err = json.Unmarshal(file, tc)
+	decoder := json.NewDecoder(bytes.NewReader(file))
+	decoder.UseNumber()
+	err = decoder.Decode(tc)
 	return tc, err
 }
 
diff --git a/convert_test.go b/convert_test.go
index eaad39d2..8b9dbb9e 100644
--- a/convert_test.go
+++ b/convert_test.go
@@ -83,10 +83,7 @@ func TestDumpAndLoadYAML(t *testing.T) {
 	if !assert.NoError(t, err) {
 		t.Fail()
 	}
-	if !assert.Equal(t, tc.Config.Name, demoTestCase.Config.Name) {
-		t.Fail()
-	}
-	if !assert.Equal(t, tc.Config.BaseURL, demoTestCase.Config.BaseURL) {
+	if !assert.Equal(t, tc.Config, demoTestCase.Config) {
 		t.Fail()
 	}
 	if !assert.Equal(t, tc.TestSteps[1].Name, demoTestCase.TestSteps[1].Name()) {
diff --git a/parser.go b/parser.go
index f5179cb3..df6a356a 100644
--- a/parser.go
+++ b/parser.go
@@ -1,6 +1,7 @@
 package httpboomer
 
 import (
+	"encoding/json"
 	"fmt"
 	"log"
 	"net/url"
@@ -61,6 +62,11 @@ func parseData(raw interface{}, variablesMapping map[string]interface{}) (interf
 	rawValue := reflect.ValueOf(raw)
 	switch rawValue.Kind() {
 	case reflect.String:
+		// json.Number
+		if rawValue, ok := raw.(json.Number); ok {
+			return parseJSONNumber(rawValue)
+		}
+		// other string
 		value := rawValue.String()
 		value = strings.TrimSpace(value)
 		return parseString(value, variablesMapping)
@@ -97,6 +103,16 @@ func parseData(raw interface{}, variablesMapping map[string]interface{}) (interf
 	}
 }
 
+func parseJSONNumber(raw json.Number) (interface{}, error) {
+	if strings.Contains(raw.String(), ".") {
+		// float64
+		return raw.Float64()
+	} else {
+		// int64
+		return raw.Int64()
+	}
+}
+
 const (
 	regexVariable     = `[a-zA-Z_]\w*`    // variable name should start with a letter or underscore
 	regexFunctionName = `[a-zA-Z_]\w*`    // function name should start with a letter or underscore
@@ -252,17 +268,26 @@ func callFunc(funcName string, arguments ...interface{}) (interface{}, error) {
 
 	argumentsValue := make([]reflect.Value, len(arguments))
 	for index, argument := range arguments {
-		// ensure each argument type match
+		argumentValue := reflect.ValueOf(argument)
 		expectArgumentType := funcValue.Type().In(index)
 		actualArgumentType := reflect.TypeOf(argument)
-		if expectArgumentType != actualArgumentType {
-			// function argument type not match
-			err := fmt.Errorf("function %s argument %d type not match, expect %v, actual %v",
+
+		// type match
+		if expectArgumentType == actualArgumentType {
+			argumentsValue[index] = argumentValue
+			continue
+		}
+
+		// type not match, check if convertible
+		if !actualArgumentType.ConvertibleTo(expectArgumentType) {
+			// function argument type not match and not convertible
+			err := fmt.Errorf("function %s argument %d type is neither match nor convertible, expect %v, actual %v",
 				funcName, index, expectArgumentType, actualArgumentType)
 			log.Printf("[callFunction] error: %s", err.Error())
 			return nil, err
 		}
-		argumentsValue[index] = reflect.ValueOf(argument)
+		// convert argument to expect type
+		argumentsValue[index] = argumentValue.Convert(expectArgumentType)
 	}
 
 	log.Printf("[callFunction] func: %v, input arguments: %v", funcName, arguments)