manifest: add validity checks for Parameter

Refs. #1699.

pkg/smartcontract/manifest/parameter.go

@@ -25,6 +25,18 @@ func NewParameter(name string, typ smartcontract.ParamType) Parameter {
 	}
 }
 
+// IsValid checks Parameter consistency and correctness.
+func (p *Parameter) IsValid() error {
+	if p.Name == "" {
+		return errors.New("empty or absent name")
+	}
+	if p.Type == smartcontract.VoidType {
+		return errors.New("void parameter")
+	}
+	_, err := smartcontract.ConvertToParamType(int(p.Type))
+	return err
+}
+
 // ToStackItem converts Parameter to stackitem.Item.
 func (p *Parameter) ToStackItem() stackitem.Item {
 	return stackitem.NewStruct([]stackitem.Item{
@@ -60,6 +72,12 @@ func (p *Parameter) FromStackItem(item stackitem.Item) error {
 
 // AreValid checks all parameters for validity and consistency.
 func (p Parameters) AreValid() error {
+	for i := range p {
+		err := p[i].IsValid()
+		if err != nil {
+			return err
+		}
+	}
 	if len(p) < 2 {
 		return nil
 	}

pkg/smartcontract/manifest/parameter_test.go

@@ -9,6 +9,29 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func TestParametersAreValid(t *testing.T) {
+	ps := Parameters{}
+	require.NoError(t, ps.AreValid()) // No parameters.
+
+	ps = append(ps, Parameter{})
+	require.Error(t, ps.AreValid())
+
+	ps[0].Name = "qwerty"
+	require.NoError(t, ps.AreValid())
+
+	ps[0].Type = 0x42 // Invalid type.
+	require.Error(t, ps.AreValid())
+
+	ps[0].Type = smartcontract.VoidType
+	require.Error(t, ps.AreValid())
+
+	ps[0].Type = smartcontract.BoolType
+	require.NoError(t, ps.AreValid())
+
+	ps = append(ps, Parameter{Name: "qwerty"})
+	require.Error(t, ps.AreValid())
+}
+
 func TestParameter_ToStackItemFromStackItem(t *testing.T) {
 	p := &Parameter{
 		Name: "param",