core/signer, clef: improve ui-test flow, fix errors in uint handling (#19584)

* core/signer, clef: improve ui-test flow, fix errors in uint handling for eip-712

* core/signer: add fuzzer testcases + crashfixes

* signer: address review concerns, check sign in integer parsing

signer/core/signed_data_internal_test.go

@@ -0,0 +1,51 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+//
+package core
+
+import (
+	"math/big"
+	"testing"
+)
+
+func TestParseInteger(t *testing.T) {
+	for i, tt := range []struct {
+		t   string
+		v   interface{}
+		exp *big.Int
+	}{
+		{"uint32", "-123", nil},
+		{"int32", "-123", big.NewInt(-123)},
+		{"uint32", "0xff", big.NewInt(0xff)},
+		{"int8", "0xffff", nil},
+	} {
+		res, err := parseInteger(tt.t, tt.v)
+		if tt.exp == nil && res == nil {
+			continue
+		}
+		if tt.exp == nil && res != nil {
+			t.Errorf("test %d, got %v, expected nil", i, res)
+			continue
+		}
+		if tt.exp != nil && res == nil {
+			t.Errorf("test %d, got '%v', expected %v", i, err, tt.exp)
+			continue
+		}
+		if tt.exp.Cmp(res) != 0 {
+			t.Errorf("test %d, got %v expected %v", i, res, tt.exp)
+		}
+	}
+}