merged from gramsrv upstream

internal/store/postgres/user_lane_actor_test.go

@@ -0,0 +1,72 @@
+package postgres
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+)
+
+func TestUserLaneActorSerializesOverlapsAndAllowsUnrelatedBypass(t *testing.T) {
+	actor := newUserLaneActor()
+	releaseA, err := actor.acquire(context.Background(), 1, 2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	overlapGranted := make(chan func(), 1)
+	go func() {
+		release, err := actor.acquire(context.Background(), 2, 3)
+		if err == nil {
+			overlapGranted <- release
+		}
+	}()
+	select {
+	case release := <-overlapGranted:
+		release()
+		t.Fatal("overlapping request was granted while lane 2 was held")
+	case <-time.After(20 * time.Millisecond):
+	}
+
+	unrelatedCtx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	releaseUnrelated, err := actor.acquire(unrelatedCtx, 4, 5)
+	if err != nil {
+		t.Fatalf("unrelated request did not bypass blocked waiter: %v", err)
+	}
+	releaseUnrelated()
+	releaseA()
+	select {
+	case release := <-overlapGranted:
+		release()
+	case <-time.After(time.Second):
+		t.Fatal("overlapping request did not resume after release")
+	}
+}
+
+func TestUserLaneActorCancellationRemovesPendingRequest(t *testing.T) {
+	actor := newUserLaneActor()
+	release, err := actor.acquire(context.Background(), 10)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	done := make(chan error, 1)
+	go func() {
+		_, err := actor.acquire(ctx, 10, 11)
+		done <- err
+	}()
+	time.Sleep(20 * time.Millisecond)
+	cancel()
+	if err := <-done; !errors.Is(err, context.Canceled) {
+		t.Fatalf("canceled acquire error = %v", err)
+	}
+	release()
+	availableCtx, availableCancel := context.WithTimeout(context.Background(), time.Second)
+	defer availableCancel()
+	releaseNext, err := actor.acquire(availableCtx, 11)
+	if err != nil {
+		t.Fatalf("canceled waiter retained lane 11: %v", err)
+	}
+	releaseNext()
+}