extract_function_counted_loop.txtar

# Extract a complete counted loop and prove zero, one, and multiple-iteration behavior with local break and continue.
exec semedit refactor-extract-callable --file service.go --symbol dispatch --in-function Run --kind function --start-line 8 --end-line 18
stdout 'symbol: dispatch'
cmp service.go want/service.go
exec go test ./...

-- go.mod --
module example.com/extractcountedloop

go 1.23
-- service.go --
package sample

import "fmt"

var events []string

func Run(limit int, stopAt int) {
	for i := 0; i < limit; i++ {
		if i == 1 {
			record("skip")
			continue
		}
		if i == stopAt {
			record("stop")
			break
		}
		record(fmt.Sprint(i))
	}
	record("done")
}

func record(event string) { events = append(events, event) }
-- service_test.go --
package sample

import (
	"reflect"
	"testing"
)

func TestRunPreservesCountedLoopPaths(t *testing.T) {
	for _, test := range []struct {
		limit   int
		stopAt  int
		want    []string
	}{
		{limit: 0, stopAt: 3, want: []string{"done"}},
		{limit: 1, stopAt: 3, want: []string{"0", "done"}},
		{limit: 5, stopAt: 3, want: []string{"0", "skip", "2", "stop", "done"}},
	} {
		events = nil
		Run(test.limit, test.stopAt)
		if !reflect.DeepEqual(events, test.want) {
			t.Fatalf("Run(%d, %d) events = %v, want %v", test.limit, test.stopAt, events, test.want)
		}
	}
}
-- want/service.go --
package sample

import "fmt"

var events []string

func Run(limit int, stopAt int) {
	dispatch(limit, stopAt)
	record("done")
}

func dispatch(limit int, stopAt int) {
	for i := 0; i < limit; i++ {
		if i == 1 {
			record("skip")
			continue
		}
		if i == stopAt {
			record("stop")
			break
		}
		record(fmt.Sprint(i))
	}
}

func record(event string) { events = append(events, event) }