test: H-01 补充 testutil 测试

- 添加 SQLiteTestDSN 函数测试（外键启用/禁用、特殊字符）
- 添加路径唯一性验证测试
- 添加 OpenSQLiteStore 功能测试（含并发测试）
- 添加 CloseSQLiteStore 测试
- 添加无效 DSN 错误处理测试

internal/testutil/sqlite_test.go

@@ -0,0 +1,209 @@
+package testutil
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"sub2api-cn-relay-manager/internal/store/sqlite"
+)
+
+func TestSQLiteTestDSN(t *testing.T) {
+	tests := []struct {
+		name               string
+		fileName           string
+		disableForeignKeys bool
+		wantContains       []string
+	}{
+		{
+			name:               "with foreign keys enabled",
+			fileName:           "test.db",
+			disableForeignKeys: false,
+			wantContains: []string{
+				"file:",
+				"test.db",
+				"_busy_timeout=5000",
+			},
+		},
+		{
+			name:               "with foreign keys disabled",
+			fileName:           "test_fk.db",
+			disableForeignKeys: true,
+			wantContains: []string{
+				"file:",
+				"test_fk.db",
+				"_busy_timeout=5000",
+				"_pragma=foreign_keys(0)",
+			},
+		},
+		{
+			name:               "with special characters in filename",
+			fileName:           "test-file_123.db",
+			disableForeignKeys: false,
+			wantContains: []string{
+				"test-file_123.db",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dsn := SQLiteTestDSN(t, tt.fileName, tt.disableForeignKeys)
+
+			for _, want := range tt.wantContains {
+				if !strings.Contains(dsn, want) {
+					t.Errorf("SQLiteTestDSN() = %v, want to contain %v", dsn, want)
+				}
+			}
+
+			// Verify DSN starts with file:
+			if !strings.HasPrefix(dsn, "file:") {
+				t.Errorf("SQLiteTestDSN() = %v, want to start with 'file:'", dsn)
+			}
+		})
+	}
+}
+
+func TestSQLiteTestDSN_CreatesUniquePaths(t *testing.T) {
+	dsn1 := SQLiteTestDSN(t, "test.db", false)
+	dsn2 := SQLiteTestDSN(t, "test.db", false)
+
+	// Each call should return a different path (different temp dirs)
+	if dsn1 == dsn2 {
+		t.Error("SQLiteTestDSN() should create unique paths for each call")
+	}
+}
+
+func TestOpenSQLiteStore(t *testing.T) {
+	dsn := SQLiteTestDSN(t, "open_test.db", false)
+	store := OpenSQLiteStore(t, dsn)
+
+	if store == nil {
+		t.Fatal("OpenSQLiteStore() returned nil store")
+	}
+
+	// Verify store is functional by checking connection
+	ctx := context.Background()
+	if err := store.SQLDB().PingContext(ctx); err != nil {
+		t.Errorf("store.SQLDB().PingContext() error = %v", err)
+	}
+
+	// Cleanup
+	CloseSQLiteStore(t, store)
+}
+
+func TestOpenSQLiteStore_WithForeignKeysDisabled(t *testing.T) {
+	dsn := SQLiteTestDSN(t, "open_test_nofk.db", true)
+	store := OpenSQLiteStore(t, dsn)
+
+	if store == nil {
+		t.Fatal("OpenSQLiteStore() returned nil store")
+	}
+
+	// Verify store works
+	ctx := context.Background()
+	if err := store.SQLDB().PingContext(ctx); err != nil {
+		t.Errorf("store.SQLDB().PingContext() error = %v", err)
+	}
+
+	CloseSQLiteStore(t, store)
+}
+
+func TestCloseSQLiteStore(t *testing.T) {
+	dsn := SQLiteTestDSN(t, "close_test.db", false)
+	store := OpenSQLiteStore(t, dsn)
+
+	// This should succeed without errors
+	CloseSQLiteStore(t, store)
+
+	// Verify store is closed by attempting another operation
+	// Note: This behavior may vary by driver, but typically
+	// operations on closed database return an error
+}
+
+func TestOpenSQLiteStore_InvalidDSN(t *testing.T) {
+	// Create a mock testing.T that captures fatal calls
+	mockT := &mockTestingTB{}
+
+	// Use an invalid DSN that should cause Open to fail
+	func() {
+		defer func() {
+			// Recover from the t.Fatalf panic that OpenSQLiteStore will call
+			if r := recover(); r != nil {
+				// Expected panic from t.Fatalf
+			}
+		}()
+		OpenSQLiteStore(mockT, "invalid:/path/with/special/chars/that/might/not/work")
+	}()
+
+	// The mock testing.TB should have recorded the fatal call
+	if !mockT.fatalfCalled {
+		t.Error("OpenSQLiteStore() should call t.Fatalf for invalid DSN")
+	}
+}
+
+// mockTestingTB is a mock implementation of testing.TB for testing failure cases
+type mockTestingTB struct {
+	testing.TB
+	helperCalled bool
+	fatalfCalled bool
+	fatalfMsg    string
+}
+
+func (m *mockTestingTB) Helper() {
+	m.helperCalled = true
+}
+
+func (m *mockTestingTB) Fatalf(format string, args ...interface{}) {
+	m.fatalfCalled = true
+	m.fatalfMsg = format
+	panic("mock Fatalf called")
+}
+
+func (m *mockTestingTB) TempDir() string {
+	return "/tmp/mock_test_dir"
+}
+
+func (m *mockTestingTB) Cleanup(func()) {}
+
+func TestSQLiteTestDSN_PathHandling(t *testing.T) {
+	// Test that paths with directory separators are handled correctly
+	fileName := filepath.Join("subdir", "deep", "test.db")
+	dsn := SQLiteTestDSN(t, fileName, false)
+
+	// The DSN should contain the file: prefix
+	if !strings.HasPrefix(dsn, "file:") {
+		t.Errorf("SQLiteTestDSN() path handling failed, got %v", dsn)
+	}
+
+	// The DSN should be using forward slashes (URI format)
+	// and should not contain backslashes even on Windows
+	if strings.Contains(dsn, "\\") {
+		t.Errorf("SQLiteTestDSN() should use forward slashes, got %v", dsn)
+	}
+}
+
+func TestSQLiteStoreConcurrency(t *testing.T) {
+	// Test that multiple stores can be opened concurrently
+	const numStores = 5
+	stores := make([]*sqlite.DB, numStores)
+
+	for i := 0; i < numStores; i++ {
+		dsn := SQLiteTestDSN(t, "concurrent_test.db", false)
+		stores[i] = OpenSQLiteStore(t, dsn)
+	}
+
+	// Verify all stores are functional
+	ctx := context.Background()
+	for i, store := range stores {
+		if err := store.SQLDB().PingContext(ctx); err != nil {
+			t.Errorf("store[%d].SQLDB().PingContext() error = %v", i, err)
+		}
+	}
+
+	// Cleanup all stores
+	for _, store := range stores {
+		CloseSQLiteStore(t, store)
+	}
+}