@Test
public void shouldReturnAndConvertMatchingEnvironmentVariableWithUnderscore() {

    environmentVariables.put("APP__ABC_XYZ", "value1");
    assertEquals(
        Collections.singletonMap("app.abc_xyz", "value1"),
        new EnvironmentVariableProperties(
            environmentVariables,
            "APP__.+"
        ).getProperties()
    );
}