// Copyright (c) 2023 IBM Corp.
// All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package function

import (
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestCache(t *testing.T) {
	var count int

	withSideEffect := func(n int) int {
		count++
		return n
	}

	cached := Cache(withSideEffect)

	assert.Equal(t, 0, count)

	assert.Equal(t, 10, cached(10))
	assert.Equal(t, 1, count)

	assert.Equal(t, 10, cached(10))
	assert.Equal(t, 1, count)

	assert.Equal(t, 20, cached(20))
	assert.Equal(t, 2, count)

	assert.Equal(t, 20, cached(20))
	assert.Equal(t, 2, count)

	assert.Equal(t, 10, cached(10))
	assert.Equal(t, 2, count)
}