feat: 系统性改进后端测试体系

- 新增 6 个测试场景 (config load pipe, handler errors, service aggregation, engine degradation, openai decoder edges, negative tests)
- 更新测试工具规格 (mockgen, in-memory SQLite)
- 覆盖率目标从 >80% 提升至 >85%
- 新增 test-unit 和 test-integration Makefile 命令
- 新增死代码清理和 mockgen 需求
- 归档变更至 openspec/changes/archive/2026-04-22-improve-backend-testing/

backend/tests/mocks/mock_provider_repository.go

@@ -0,0 +1,113 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: provider_repo.go
+//
+// Generated by this command:
+//
+//	mockgen -source=provider_repo.go -destination=../../tests/mocks/mock_provider_repository.go -package=mocks
+//
+
+// Package mocks is a generated GoMock package.
+package mocks
+
+import (
+	domain "nex/backend/internal/domain"
+	reflect "reflect"
+
+	gomock "go.uber.org/mock/gomock"
+)
+
+// MockProviderRepository is a mock of ProviderRepository interface.
+type MockProviderRepository struct {
+	ctrl     *gomock.Controller
+	recorder *MockProviderRepositoryMockRecorder
+	isgomock struct{}
+}
+
+// MockProviderRepositoryMockRecorder is the mock recorder for MockProviderRepository.
+type MockProviderRepositoryMockRecorder struct {
+	mock *MockProviderRepository
+}
+
+// NewMockProviderRepository creates a new mock instance.
+func NewMockProviderRepository(ctrl *gomock.Controller) *MockProviderRepository {
+	mock := &MockProviderRepository{ctrl: ctrl}
+	mock.recorder = &MockProviderRepositoryMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockProviderRepository) EXPECT() *MockProviderRepositoryMockRecorder {
+	return m.recorder
+}
+
+// Create mocks base method.
+func (m *MockProviderRepository) Create(provider *domain.Provider) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Create", provider)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// Create indicates an expected call of Create.
+func (mr *MockProviderRepositoryMockRecorder) Create(provider any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Create", reflect.TypeOf((*MockProviderRepository)(nil).Create), provider)
+}
+
+// Delete mocks base method.
+func (m *MockProviderRepository) Delete(id string) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Delete", id)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// Delete indicates an expected call of Delete.
+func (mr *MockProviderRepositoryMockRecorder) Delete(id any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Delete", reflect.TypeOf((*MockProviderRepository)(nil).Delete), id)
+}
+
+// GetByID mocks base method.
+func (m *MockProviderRepository) GetByID(id string) (*domain.Provider, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "GetByID", id)
+	ret0, _ := ret[0].(*domain.Provider)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// GetByID indicates an expected call of GetByID.
+func (mr *MockProviderRepositoryMockRecorder) GetByID(id any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetByID", reflect.TypeOf((*MockProviderRepository)(nil).GetByID), id)
+}
+
+// List mocks base method.
+func (m *MockProviderRepository) List() ([]domain.Provider, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "List")
+	ret0, _ := ret[0].([]domain.Provider)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// List indicates an expected call of List.
+func (mr *MockProviderRepositoryMockRecorder) List() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "List", reflect.TypeOf((*MockProviderRepository)(nil).List))
+}
+
+// Update mocks base method.
+func (m *MockProviderRepository) Update(id string, updates map[string]any) error {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Update", id, updates)
+	ret0, _ := ret[0].(error)
+	return ret0
+}
+
+// Update indicates an expected call of Update.
+func (mr *MockProviderRepositoryMockRecorder) Update(id, updates any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Update", reflect.TypeOf((*MockProviderRepository)(nil).Update), id, updates)
+}