Review LLM concurrency refactor

internal/framework/validators/llm_validators_test.go

@@ -3,6 +3,7 @@ package validators
 import (
 	"context"
 	"errors"
+	"runtime"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -24,6 +25,8 @@ type fakeStructuredLLMClient struct {
 type sleepingValidationClient struct {
 	inFlight    int32
 	maxInFlight int32
+	entered     chan struct{}
+	release     chan struct{}
 }
 
 type boundedScheduler struct {
@@ -53,8 +56,11 @@ func (c *sleepingValidationClient) CompleteStructured(ctx context.Context, req S
 			break
 		}
 	}
+	if c.entered != nil {
+		c.entered <- struct{}{}
+	}
 	select {
-	case <-time.After(20 * time.Millisecond):
+	case <-c.release:
 	case <-ctx.Done():
 		atomic.AddInt32(&c.inFlight, -1)
 		return StructuredCompletionResponse{}, ctx.Err()
@@ -245,7 +251,10 @@ func TestLLMBackedValidatorUnknownProposalIndexFails(t *testing.T) {
 
 func TestLLMBackedValidatorRespectsSchedulerConcurrency(t *testing.T) {
 	scheduler := newBoundedScheduler(2)
-	client := &sleepingValidationClient{}
+	client := &sleepingValidationClient{
+		entered: make(chan struct{}, 16),
+		release: make(chan struct{}),
+	}
 	v, err := NewLLMBackedValidator("spoken_form_plausibility_review", LLMValidatorTypeSpokenFormPlausibility, "test-model")
 	if err != nil {
 		t.Fatalf("new validator error: %v", err)
@@ -264,6 +273,8 @@ func TestLLMBackedValidatorRespectsSchedulerConcurrency(t *testing.T) {
 			}
 		}()
 	}
+	waitForValidationEntries(t, client.entered, 2)
+	close(client.release)
 	wg.Wait()
 
 	if got := atomic.LoadInt32(&client.maxInFlight); got > 2 {
@@ -273,3 +284,20 @@ func TestLLMBackedValidatorRespectsSchedulerConcurrency(t *testing.T) {
 		t.Fatalf("expected observed concurrency of at least 2, got %d", got)
 	}
 }
+
+func waitForValidationEntries(t *testing.T, entered <-chan struct{}, want int) {
+	t.Helper()
+	deadline := time.Now().Add(300 * time.Millisecond)
+	got := 0
+	for got < want && time.Now().Before(deadline) {
+		select {
+		case <-entered:
+			got++
+		default:
+			runtime.Gosched()
+		}
+	}
+	if got < want {
+		t.Fatalf("timed out waiting for %d validator calls to enter (got %d)", want, got)
+	}
+}