CountriesQueryNetworkFailure.swift

extension WorldAPITests {
    func test_CountriesQueryNetworkFailure() {

        guard let results = MockGraphQLQuery.countries.responseObject else {
            XCTFail()
            return
        }

        let query = CountriesQuery()

        withCache(initialRecords: [:]) { cache in

            let store = ApolloStore(cache: cache)
            let transport = MockNetworkTransport(body: results,
                                                 simulateNetworkFailure: true)
            let client = ApolloClient(networkTransport: transport,
                                      store: store)

            let worldStore = World.Store(client: client)

            let expectation = self.expectation(description: "Fetching query")

            worldStore.fetchAllCountries { result in
                defer {
                    expectation.fulfill()
                }

                switch result {
                case let .failure(error):
                    XCTAssertEqual(error, World.StoreError.network)
                    return
                case .success:
                   XCTFail()
                }
            }

            self.waitForExpectations(timeout: 5, handler: nil)
        }
    }
}