@Test
public void testFromProperties() throws IOException {

    Properties properties = new Properties();
    InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("config.properties");
    properties.load(inputStream);
    Config cfg = new Config(properties);
    assertEquals(100, cfg.getInt("a"));
    assertEquals("hello", cfg.get("b"));
    assertTrue(cfg.getBoolean("c"));
}