private void addToTracker(String varName, String key, String value) {
        try {
            Field field = tracker.getClass().getDeclaredField(varName);
            field.setAccessible(true);
            Map<String, String> map = (Map<String, String>) field.get(tracker);
            map.put(key, value);
        } catch (NoSuchFieldException | IllegalAccessException e) {
            throw new AssertionError(e);
        }
    }
This test need to be refactored. In fact, testing Mojos must be setup correctly at all. Blame on me that there are so
few tests ...
src/test/java/io/fabric8/maven/docker/service/RunServiceTest.java