did: add a MustParse function

did/did.go

@@ -116,3 +116,11 @@ func Parse(str string) (DID, error) {
 	buf = append(buf, suffix...)
 	return DID{str: string(buf), code: DIDCore}, nil
 }
+
+func MustParse(str string) DID {
+	did, err := Parse(str)
+	if err != nil {
+		panic(err)
+	}
+	return did
+}

did/did_test.go

@@ -2,6 +2,8 @@ package did
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestParseDIDKey(t *testing.T) {
@@ -15,6 +17,18 @@ func TestParseDIDKey(t *testing.T) {
 	}
 }
 
+func TestMustParseDIDKey(t *testing.T) {
+	str := "did:key:z6Mkod5Jr3yd5SC7UDueqK4dAAw5xYJYjksy722tA9Boxc4z"
+	require.NotPanics(t, func() {
+		d := MustParse(str)
+		require.Equal(t, str, d.String())
+	})
+	str = "did:key:z7Mkod5Jr3yd5SC7UDueqK4dAAw5xYJYjksy722tA9Boxc4z"
+	require.Panics(t, func() {
+		MustParse(str)
+	})
+}
+
 func TestDecodeDIDKey(t *testing.T) {
 	str := "did:key:z6Mkod5Jr3yd5SC7UDueqK4dAAw5xYJYjksy722tA9Boxc4z"
 	d0, err := Parse(str)