diff --git a/core/history/history_test.go b/core/history/history_test.go
index c1ce7d73e..470c95114 100644
--- a/core/history/history_test.go
+++ b/core/history/history_test.go
@@ -1134,14 +1134,13 @@ func TestHistory_Show(t *testing.T) {
 			Model:    &pb.Change{},
 		}
 
-		heads := []string{"id", "id1"}
 		changesMap := map[string][]*objecttree.Change{
-			"id1 id": {root, ch1},
-			"id id1": {root, ch},
+			"id id1": {root, ch1},
+			"id1 id": {root, ch},
 			objectId: {root, ch, ch1},
 		}
 
-		h := newFixtureShow(t, changesMap, heads, objectId, spaceID)
+		h := newFixtureShow(t, changesMap, objectId, spaceID)
 
 		// when
 		fullId := domain.FullID{ObjectID: objectId, SpaceID: spaceID}
@@ -1214,7 +1213,7 @@ func newFixtureDiffVersions(t *testing.T,
 	}
 }
 
-func newFixtureShow(t *testing.T, changes map[string][]*objecttree.Change, heads []string, objectId, spaceID string) *historyFixture {
+func newFixtureShow(t *testing.T, changes map[string][]*objecttree.Change, objectId, spaceID string) *historyFixture {
 	spaceService := mock_space.NewMockService(t)
 	space := mock_clientspace.NewMockSpace(t)
 	ctrl := gomock.NewController(t)
@@ -1232,7 +1231,7 @@ func newFixtureShow(t *testing.T, changes map[string][]*objecttree.Change, heads
 			return &historyStub{
 				objectId: objectId,
 				changes:  chs,
-				heads:    heads,
+				heads:    opts.Heads,
 			}, nil
 		}).AnyTimes()
 		space.EXPECT().TreeBuilder().Return(treeBuilder)
diff --git a/core/payments/emailcollector/emailcollector_test.go b/core/payments/emailcollector/emailcollector_test.go
index e1726cffc..8c18b73a5 100644
--- a/core/payments/emailcollector/emailcollector_test.go
+++ b/core/payments/emailcollector/emailcollector_test.go
@@ -1,6 +1,7 @@
 package emailcollector
 
 import (
+	"sync/atomic"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -188,10 +189,10 @@ func TestEmailCollector(t *testing.T) {
 
 	t.Run("should handle concurrent requests", func(t *testing.T) {
 		// Given
-		var callCount int
+		var callCount atomic.Uint32
 		collector := &mockEmailCollector{
 			onSetRequest: func(req *pb.RpcMembershipGetVerificationEmailRequest) error {
-				callCount++
+				callCount.Add(1)
 				assert.Equal(t, "test@example.com", req.Email)
 				return nil
 			},
@@ -214,6 +215,6 @@ func TestEmailCollector(t *testing.T) {
 		for i := 0; i < 10; i++ {
 			<-done
 		}
-		assert.Equal(t, 10, callCount)
+		assert.Equal(t, uint32(10), callCount.Load())
 	})
 }