package hash

import (
	"github.com/tursom/checksum/assert"
	"hash"
	"hash/crc32"
	"testing"
)

func TestCrc32Koopman_Finish(t *testing.T) {
	type fields struct {
		d hash.Hash
	}
	tests := []struct {
		name    string
		fields  fields
		builder func(m *Crc32Koopman)
		want    []byte
	}{
		{
			"nil",
			fields{},
			nil,
			crc32.New(KoopmanTable).Sum(nil),
		},
		{
			"hello",
			fields{},
			func(m *Crc32Koopman) {
				m.Append([]byte("hello"))
			},
			crc32KoopmanSum([]byte("hello")),
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			m := &Crc32Koopman{
				d: tt.fields.d,
			}
			if tt.builder != nil {
				tt.builder(m)
			}

			assert.Equals(t, m.Finish(), tt.want)
		})
	}
}

func crc32KoopmanSum(b []byte) []byte {
	h := crc32.New(KoopmanTable)
	h.Write(b)
	return h.Sum(nil)
}

func TestCrc32Koopman_String(t *testing.T) {
	assert.Equals(t, (&Crc32Koopman{}).String(), "crc32koopman")
}