### Question:
EnvironmentVariableLoader implements ConfigurationLoader { @Override public Properties loadConfigurations() { Properties properties = new Properties(); Map<String, String> envVars = System.getenv(); envVars.forEach(properties::put); return properties; }  @Override Properties loadConfigurations();  }### Answer:
@Test public void loadConfigurations() { EnvironmentVariableLoader loader = new EnvironmentVariableLoader(); Properties properties = loader.loadConfigurations(); Set<Map.Entry<String, String>> systemEnvEntrySet = System.getenv().entrySet(); for (Map.Entry<String, String> systemEnvEntry : systemEnvEntrySet) { String key = systemEnvEntry.getKey(); String value = systemEnvEntry.getValue(); assertNotNull(properties.getProperty(key)); assertEquals(value, properties.getProperty(key)); } }