Mock InfluxDB client to test a MetricCollector class

Question

I have a metrics collector that store data on InfluxDB, I want to test the methods to store that metrics. I'm trying it but I'm not able to mock the InfluxDB client. I don't want to point to a real InfluxDB on the test environment.

Everything I've achieved so far are some "null pointer exceptions" and conection refused.

This is my test (using TestNG). What am I doing wrong?

    @Test
    public void validateMetrics() {
        String influxHost = "http://localhost";
        String credentials = "admin:admin";
        String influxDatabaseName = "testDataBase";
        influxDB = InfluxDBFactory.connect(influxHost, credentials.split(":")[0], credentials.split(":")[1]);

        MetricsCollector metricsCollector = null;

        try {
            String hostName = "test-server-01";
            int statusValue = 1;
            metricsCollector = new MetricsCollector(influxDB);


            BatchPoints metrics = metricsCollector.initBatchPoint(influxDatabaseName); 
            Point point = metricsCollector.setMetric(hostName, "status", statusValue);
            metrics = metricsCollector.addToMetrics(metrics, point);

            Assert.assertTrue(metrics.getPoints().get(0).lineProtocol().contains(hostName));
            Assert.assertTrue(metrics.getPoints().get(0).lineProtocol().contains("status=" + statusValue));
        } finally {
           if (metricsCollector != null) {
                metricsCollector.closeConnection();
            }
        }
    }

Answer 1

I totally misunderstanding how mockito works. Here is my fixed code:

    @Mock private InfluxDB influxDB;
    @Test
    public void validateMetrics() {
        MetricsCollector metricsCollector = null;
        String influxHost = "http://localhost";
        String credentials = "admin:admin";
        String influxDatabaseName = "testDataBase";

        influxDB = InfluxDBFactory.connect(influxHost, credentials.split(":")[0], credentials.split(":")[1]);

       try {
            String hostName = "test-server-01";
            int statusValue = 1;
            metricsCollector = new MetricsCollector(influxDB);

            BatchPoints metrics = metricsCollector.initBatchPoint(influxDatabaseName); 
            Point point = metricsCollector.setMetric(hostName, "status", statusValue);
            metrics = metricsCollector.addToMetrics(metrics, point);

            Assert.assertTrue(metrics.getPoints().get(0).lineProtocol().contains(hostName));
            Assert.assertTrue(metrics.getPoints().get(0).lineProtocol().contains("status=" + statusValue));
       } finally {
           if (metricsCollector != null) {
                metricsCollector.closeConnection();
            }
       }
    }

Yep, added that simple "mock" annotation and all works fine.