// (c) 2020-2021, Lux Industries, Inc.
//
// This file is a derived work, based on the go-ethereum library whose original
// notices appear below.
//
// It is distributed under a license compatible with the licensing terms of the
// original code from which it is derived.
//
// Much love to the original authors for their work.
// **********
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package core

import (
	"testing"
)

// TODO: Add TestHeaderVerification

func TestCalcGasLimit(t *testing.T) {
	for i, tc := range []struct {
		pGasLimit uint64
		max       uint64
		min       uint64
	}{
		{20000000, 20019530, 19980470},
		{40000000, 40039061, 39960939},
	} {
		// Increase
		if have, want := CalcGasLimit(0, tc.pGasLimit, 2*tc.pGasLimit, 2*tc.pGasLimit), tc.max; have != want {
			t.Errorf("test %d: have %d want <%d", i, have, want)
		}
		// Decrease
		if have, want := CalcGasLimit(0, tc.pGasLimit, 0, 0), tc.min; have != want {
			t.Errorf("test %d: have %d want >%d", i, have, want)
		}
		// Small decrease
		if have, want := CalcGasLimit(0, tc.pGasLimit, tc.pGasLimit-1, tc.pGasLimit-1), tc.pGasLimit-1; have != want {
			t.Errorf("test %d: have %d want %d", i, have, want)
		}
		// Small increase
		if have, want := CalcGasLimit(0, tc.pGasLimit, tc.pGasLimit+1, tc.pGasLimit+1), tc.pGasLimit+1; have != want {
			t.Errorf("test %d: have %d want %d", i, have, want)
		}
		// No change
		if have, want := CalcGasLimit(0, tc.pGasLimit, tc.pGasLimit, tc.pGasLimit), tc.pGasLimit; have != want {
			t.Errorf("test %d: have %d want %d", i, have, want)
		}
	}
}