test/test_watch.cpp

#include "types.hpp"
#include "watch.hpp"

#include <experimental/filesystem>
#include <fstream>

#include <gtest/gtest.h>

static constexpr auto TRIGGER_FILE = "/tmp/" __BASE_FILE__ "netif_state";

namespace fs = std::experimental::filesystem;

class WatchTest : public ::testing::Test
{
  public:
    // systemd event handler
    sd_event* events;

    // Need this so that events can be initialized.
    int rc;

    // Gets called as part of each TEST_F construction
    WatchTest() : rc(sd_event_default(&events)), eventPtr(events)
    {
        // Create a file containing DNS entries like in netif/state
        std::ofstream file(TRIGGER_FILE);
        file << "";

        // Check for successful creation of
        // event handler
        EXPECT_GE(rc, 0);
    }

    // Gets called as part of each TEST_F destruction
    ~WatchTest()
    {
        if (fs::exists(TRIGGER_FILE))
        {
            fs::remove(TRIGGER_FILE);
        }
    }

    // unique_ptr for sd_event
    phosphor::network::EventPtr eventPtr;

    // Count of callback invocation
    int count = 0;

    // This is supposed to get hit twice
    // Once at the beginning to see if there is anything
    // and the second time when the data is fired.
    void callBackHandler(const fs::path& file)
    {
        count++;

        // Expect that the file is what we wanted
        EXPECT_EQ(file, TRIGGER_FILE);
    }
};

/** @brief Makes sure that the inotify event is fired
 */
TEST_F(WatchTest, validateEventNotification)
{
    // Create a watch object and register the handler
    phosphor::network::inotify::Watch watch(
        eventPtr, TRIGGER_FILE,
        std::bind(&WatchTest::callBackHandler, this, std::placeholders::_1));

    // Reading the event post subscription
    callBackHandler(TRIGGER_FILE);

    // Callback function must have hit by now
    EXPECT_EQ(1, count);

    // Make a run and see that no changes
    sd_event_run(eventPtr.get(), 10);
    EXPECT_EQ(1, count);

    // Pump the data and get notification
    {
        std::ofstream file(TRIGGER_FILE);
        file << "DNS=1.2.3.4\n";
    }

    sd_event_run(eventPtr.get(), 10);
    EXPECT_EQ(2, count);
}