Function makeTestDuplicateSequence

reader_test.go:1884–1920

makeTestDuplicateSequence creates messages for compacted log testing All keys and values are 4 characters long to tightly control how many messages are per log segment.

()

// All keys and values are 4 characters long to tightly control how many
// messages are per log segment.
func makeTestDuplicateSequence() []Message {
	var msgs []Message
	// `n` is an increasing counter so it is never compacted.
	n := 0
	// `i` determines how many compacted records to create
	for i := 0; i < 5; i++ {
		// `j` is how many times the current pattern repeats. We repeat because
		// as long as we have a pattern that is slightly larger/smaller than
		// the log segment size then if we repeat enough it will eventually
		// try all configurations.
		for j := 0; j < 30; j++ {
			msgs = append(msgs, Message{
				Key:   []byte(fmt.Sprintf("%04d", n)),
				Value: []byte(fmt.Sprintf("%04d", n)),
			})
			n++

			// This produces the duplicated messages to compact.
			for k := 0; k < i; k++ {
				msgs = append(msgs, Message{
					Key:   []byte("dup_"),
					Value: []byte("dup_"),
				})
			}
		}
	}

	// "end markers" to force duplicate message outside of the last segment of
	// the log so that they can all be compacted.
	for i := 0; i < 10; i++ {
		msgs = append(msgs, Message{
			Key:   []byte(fmt.Sprintf("e-%02d", i)),
			Value: []byte(fmt.Sprintf("e-%02d", i)),
		})
	}
	return msgs
}

// countKeys counts unique keys from given Message slice.
func countKeys(msgs []Message) int {