1 files changed, 167 insertions, 0 deletions
diff --git a/src/go/collectors/go.d.plugin/agent/discovery/sd/discoverer/netlisteners/sim_test.go b/src/go/collectors/go.d.plugin/agent/discovery/sd/discoverer/netlisteners/sim_test.go
new file mode 100644
index 000000000..ad90f8278
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/agent/discovery/sd/discoverer/netlisteners/sim_test.go
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package netlisteners
+
+import (
+	"context"
+	"errors"
+	"slices"
+	"sort"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/netdata/netdata/go/go.d.plugin/agent/discovery/sd/model"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type listenersCli interface {
+	addListener(s string)
+	removeListener(s string)
+}
+
+type discoverySim struct {
+	listenersCli func(cli listenersCli, interval, expiry time.Duration)
+	wantGroups   []model.TargetGroup
+}
+
+func (sim *discoverySim) run(t *testing.T) {
+	d, err := NewDiscoverer(Config{
+		Source: "",
+		Tags:   "netlisteners",
+	})
+	require.NoError(t, err)
+
+	mock := newMockLocalListenersExec()
+
+	d.ll = mock
+
+	d.interval = time.Millisecond * 100
+	d.expiryTime = time.Second * 1
+
+	seen := make(map[string]model.TargetGroup)
+	ctx, cancel := context.WithCancel(context.Background())
+	in := make(chan []model.TargetGroup)
+	var wg sync.WaitGroup
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		d.Discover(ctx, in)
+	}()
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case tggs := <-in:
+				for _, tgg := range tggs {
+					seen[tgg.Source()] = tgg
+				}
+			}
+		}
+	}()
+
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		wg.Wait()
+	}()
+
+	select {
+	case <-d.started:
+	case <-time.After(time.Second * 3):
+		require.Fail(t, "discovery failed to start")
+	}
+
+	sim.listenersCli(mock, d.interval, d.expiryTime)
+
+	cancel()
+
+	select {
+	case <-done:
+	case <-time.After(time.Second * 3):
+		require.Fail(t, "discovery hasn't finished after cancel")
+	}
+
+	var tggs []model.TargetGroup
+	for _, tgg := range seen {
+		tggs = append(tggs, tgg)
+	}
+
+	sortTargetGroups(tggs)
+	sortTargetGroups(sim.wantGroups)
+
+	wantLen, gotLen := calcTargets(sim.wantGroups), calcTargets(tggs)
+	assert.Equalf(t, wantLen, gotLen, "different len (want %d got %d)", wantLen, gotLen)
+	assert.Equal(t, sim.wantGroups, tggs)
+}
+
+func newMockLocalListenersExec() *mockLocalListenersExec {
+	return &mockLocalListenersExec{}
+}
+
+type mockLocalListenersExec struct {
+	errResponse bool
+	mux         sync.Mutex
+	listeners   []string
+}
+
+func (m *mockLocalListenersExec) addListener(s string) {
+	m.mux.Lock()
+	defer m.mux.Unlock()
+
+	m.listeners = append(m.listeners, s)
+}
+
+func (m *mockLocalListenersExec) removeListener(s string) {
+	m.mux.Lock()
+	defer m.mux.Unlock()
+
+	if i := slices.Index(m.listeners, s); i != -1 {
+		m.listeners = append(m.listeners[:i], m.listeners[i+1:]...)
+	}
+}
+
+func (m *mockLocalListenersExec) discover(context.Context) ([]byte, error) {
+	if m.errResponse {
+		return nil, errors.New("mock discover() error")
+	}
+
+	m.mux.Lock()
+	defer m.mux.Unlock()
+
+	var buf strings.Builder
+	for _, s := range m.listeners {
+		buf.WriteString(s)
+		buf.WriteByte('\n')
+	}
+
+	return []byte(buf.String()), nil
+}
+
+func calcTargets(tggs []model.TargetGroup) int {
+	var n int
+	for _, tgg := range tggs {
+		n += len(tgg.Targets())
+	}
+	return n
+}
+
+func sortTargetGroups(tggs []model.TargetGroup) {
+	if len(tggs) == 0 {
+		return
+	}
+	sort.Slice(tggs, func(i, j int) bool { return tggs[i].Source() < tggs[j].Source() })
+
+	for idx := range tggs {
+		tgts := tggs[idx].Targets()
+		sort.Slice(tgts, func(i, j int) bool { return tgts[i].Hash() < tgts[j].Hash() })
+	}
+}