From e06ecacf57e14630f1cd783af0c88854c26f41cc Mon Sep 17 00:00:00 2001
From: Dmitrii Stepanov <d.stepanov@yadro.com>
Date: Thu, 10 Apr 2025 16:04:04 +0300
Subject: [PATCH] [#1705] engine: Use condition var for evacuation unit tests

To know exactly when the evacuation was completed,
a conditional variable was added.

Closes #1705

Change-Id: I86f6d7d2ad2b9759905b6b5e9341008cb74f5dfd
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
---
 pkg/local_object_storage/engine/engine.go      | 16 +++++++++++-----
 .../engine/evacuate_limiter.go                 |  6 +++++-
 .../engine/evacuate_test.go                    | 18 +++++++++++++-----
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/pkg/local_object_storage/engine/engine.go b/pkg/local_object_storage/engine/engine.go
index a915c9bd6..1d33c0592 100644
--- a/pkg/local_object_storage/engine/engine.go
+++ b/pkg/local_object_storage/engine/engine.go
@@ -212,12 +212,18 @@ func New(opts ...Option) *StorageEngine {
 		opts[i](c)
 	}
 
+	evLimMtx := &sync.RWMutex{}
+	evLimCond := sync.NewCond(evLimMtx)
+
 	return &StorageEngine{
-		cfg:             c,
-		shards:          make(map[string]hashedShard),
-		closeCh:         make(chan struct{}),
-		setModeCh:       make(chan setModeRequest),
-		evacuateLimiter: &evacuationLimiter{},
+		cfg:       c,
+		shards:    make(map[string]hashedShard),
+		closeCh:   make(chan struct{}),
+		setModeCh: make(chan setModeRequest),
+		evacuateLimiter: &evacuationLimiter{
+			guard:      evLimMtx,
+			statusCond: evLimCond,
+		},
 	}
 }
 
diff --git a/pkg/local_object_storage/engine/evacuate_limiter.go b/pkg/local_object_storage/engine/evacuate_limiter.go
index 3dd7494be..b75e8686d 100644
--- a/pkg/local_object_storage/engine/evacuate_limiter.go
+++ b/pkg/local_object_storage/engine/evacuate_limiter.go
@@ -139,7 +139,8 @@ type evacuationLimiter struct {
 	eg     *errgroup.Group
 	cancel context.CancelFunc
 
-	guard sync.RWMutex
+	guard      *sync.RWMutex
+	statusCond *sync.Cond // used in unit tests
 }
 
 func (l *evacuationLimiter) TryStart(ctx context.Context, shardIDs []string, result *EvacuateShardRes) (*errgroup.Group, context.Context, error) {
@@ -165,6 +166,7 @@ func (l *evacuationLimiter) TryStart(ctx context.Context, shardIDs []string, res
 		startedAt:    time.Now().UTC(),
 		result:       result,
 	}
+	l.statusCond.Broadcast()
 
 	return l.eg, egCtx, nil
 }
@@ -180,6 +182,7 @@ func (l *evacuationLimiter) Complete(err error) {
 	l.state.processState = EvacuateProcessStateCompleted
 	l.state.errMessage = errMsq
 	l.state.finishedAt = time.Now().UTC()
+	l.statusCond.Broadcast()
 
 	l.eg = nil
 }
@@ -214,6 +217,7 @@ func (l *evacuationLimiter) ResetEvacuationStatus() error {
 	l.state = EvacuationState{}
 	l.eg = nil
 	l.cancel = nil
+	l.statusCond.Broadcast()
 
 	return nil
 }
diff --git a/pkg/local_object_storage/engine/evacuate_test.go b/pkg/local_object_storage/engine/evacuate_test.go
index 359e49481..f2ba7d994 100644
--- a/pkg/local_object_storage/engine/evacuate_test.go
+++ b/pkg/local_object_storage/engine/evacuate_test.go
@@ -204,11 +204,10 @@ func TestEvacuateShardObjects(t *testing.T) {
 func testWaitForEvacuationCompleted(t *testing.T, e *StorageEngine) *EvacuationState {
 	var st *EvacuationState
 	var err error
-	require.Eventually(t, func() bool {
-		st, err = e.GetEvacuationState(context.Background())
-		require.NoError(t, err)
-		return st.ProcessingStatus() == EvacuateProcessStateCompleted
-	}, 6*time.Second, 10*time.Millisecond)
+	e.evacuateLimiter.waitForCompleted()
+	st, err = e.GetEvacuationState(context.Background())
+	require.NoError(t, err)
+	require.Equal(t, EvacuateProcessStateCompleted, st.ProcessingStatus())
 	return st
 }
 
@@ -817,3 +816,12 @@ func TestEvacuateShardObjectsRepOneOnlyBench(t *testing.T) {
 	t.Logf("evacuate took %v\n", time.Since(start))
 	require.NoError(t, err)
 }
+
+func (l *evacuationLimiter) waitForCompleted() {
+	l.guard.Lock()
+	defer l.guard.Unlock()
+
+	for l.state.processState != EvacuateProcessStateCompleted {
+		l.statusCond.Wait()
+	}
+}