1 files changed, 118 insertions, 0 deletions
diff --git a/internal/queue/inmemqueue/queue_test.go b/internal/queue/inmemqueue/queue_test.go
new file mode 100644
index 00000000..79847140
--- /dev/null
+++ b/internal/queue/inmemqueue/queue_test.go
@@ -0,0 +1,118 @@
+// Copyright 2026 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inmemqueue
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"testing"
+)
+
+func TestInMemory_ScheduleAndProcess(t *testing.T) {
+	ctx := context.Background()
+
+	var processed int
+	var mu sync.Mutex
+
+	processFunc := func(ctx context.Context, path, version string) (int, error) {
+		mu.Lock()
+		processed++
+		mu.Unlock()
+		return 200, nil
+	}
+
+	q := New(ctx, 2, nil, processFunc)
+
+	tests := []struct {
+		path    string
+		version string
+	}{
+		{"example.com/mod1", "v1.0.0"},
+		{"example.com/mod2", "v1.1.0"},
+		{"example.com/mod3", "v2.0.0"},
+	}
+
+	for _, tc := range tests {
+		ok, err := q.ScheduleFetch(ctx, tc.path, tc.version, nil)
+		if err != nil {
+			t.Fatalf("ScheduleFetch(%q, %q) returned error: %v", tc.path, tc.version, err)
+		}
+		if !ok {
+			t.Errorf("ScheduleFetch(%q, %q) = false, want true", tc.path, tc.version)
+		}
+	}
+
+	q.WaitForTesting(ctx)
+
+	if got, want := processed, len(tests); got != want {
+		t.Errorf("processed tasks = %d, want %d", got, want)
+	}
+}
+
+func TestInMemory_ProcessFuncError(t *testing.T) {
+	ctx := context.Background()
+
+	processFunc := func(ctx context.Context, path, version string) (int, error) {
+		return 500, errors.New("simulated fetch error")
+	}
+
+	q := New(ctx, 1, nil, processFunc)
+
+	_, err := q.ScheduleFetch(ctx, "example.com/error-mod", "v1.0.0", nil)
+	if err != nil {
+		t.Fatalf("ScheduleFetch returned error: %v", err)
+	}
+
+	// This should complete without panicking or deadlocking.
+	q.WaitForTesting(ctx)
+}
+
+func TestInMemory_WorkerConcurrency(t *testing.T) {
+	ctx := context.Background()
+	workerCount := 2
+
+	var active, max int
+	var mu sync.Mutex
+	var wg sync.WaitGroup
+
+	blockCh := make(chan struct{})
+
+	processFunc := func(ctx context.Context, path, version string) (int, error) {
+		mu.Lock()
+		active++
+		if active > max {
+			max = active
+		}
+		mu.Unlock()
+
+		<-blockCh
+
+		mu.Lock()
+		active--
+		mu.Unlock()
+		wg.Done()
+		return 200, nil
+	}
+
+	q := New(ctx, workerCount, nil, processFunc)
+
+	taskCount := 5
+	wg.Add(taskCount)
+	for range taskCount {
+		_, err := q.ScheduleFetch(ctx, "example.com/concurrent", "v1.0.0", nil)
+		if err != nil {
+			t.Fatalf("ScheduleFetch returned error: %v", err)
+		}
+	}
+
+	close(blockCh)
+	wg.Wait()
+	q.WaitForTesting(ctx)
+
+	if max > workerCount {
+		t.Errorf("max concurrent workers = %d, want <= %d", max, workerCount)
+	}
+}