Simplify node lock and various small changes

Co-authored-by: Fabian Kammel <fabian@kammel.dev>
Co-authored-by: Daniel Weiße <66256922+daniel-weisse@users.noreply.github.com>

bootstrapper/internal/clean/clean_test.go

@@ -0,0 +1,98 @@
+package clean
+
+import (
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/goleak"
+)
+
+func TestMain(m *testing.M) {
+	goleak.VerifyTestMain(m)
+}
+
+func TestNew(t *testing.T) {
+	assert := assert.New(t)
+
+	cleaner := New(&spyStopper{})
+	assert.NotNil(cleaner)
+	assert.NotEmpty(cleaner.stoppers)
+}
+
+func TestWith(t *testing.T) {
+	assert := assert.New(t)
+
+	cleaner := New().With(&spyStopper{})
+	assert.NotEmpty(cleaner.stoppers)
+}
+
+func TestClean(t *testing.T) {
+	assert := assert.New(t)
+
+	stopper := &spyStopper{}
+	cleaner := New(stopper)
+	go cleaner.Start()
+	cleaner.Clean()
+	cleaner.Done()
+	assert.Equal(int64(1), atomic.LoadInt64(&stopper.stopped))
+	// call again to make sure it doesn't panic or block or clean up again
+	cleaner.Clean()
+	assert.Equal(int64(1), atomic.LoadInt64(&stopper.stopped))
+}
+
+func TestCleanBeforeStart(t *testing.T) {
+	assert := assert.New(t)
+	// calling Clean before Start should work
+	stopper := &spyStopper{}
+	cleaner := New(stopper)
+	cleaner.Clean()
+	cleaner.Start()
+	cleaner.Done()
+	assert.Equal(int64(1), atomic.LoadInt64(&stopper.stopped))
+}
+
+func TestConcurrent(t *testing.T) {
+	assert := assert.New(t)
+	// calling Clean concurrently should call Stop exactly once
+
+	stopper := &spyStopper{}
+	cleaner := New(stopper)
+
+	parallelism := 10
+	wg := sync.WaitGroup{}
+
+	start := func() {
+		defer wg.Done()
+		cleaner.Start()
+	}
+
+	clean := func() {
+		defer wg.Done()
+		cleaner.Clean()
+	}
+
+	done := func() {
+		defer wg.Done()
+		cleaner.Done()
+	}
+
+	wg.Add(3 * parallelism)
+	for i := 0; i < parallelism; i++ {
+		go start()
+		go clean()
+		go done()
+	}
+	wg.Wait()
+	cleaner.Done()
+	assert.Equal(int64(1), atomic.LoadInt64(&stopper.stopped))
+}
+
+type spyStopper struct {
+	stopped int64
+}
+
+func (s *spyStopper) Stop() {
+	atomic.AddInt64(&s.stopped, 1)
+}