public void testGetInstantConverterBadMultipleMatches() {
        InstantConverter c = new InstantConverter() {
            public long getInstantMillis(Object object, Chronology chrono) {return 0;}
            public Chronology getChronology(Object object, DateTimeZone zone) {return null;}
            public Chronology getChronology(Object object, Chronology chrono) {return null;}
            public Class getSupportedType() {return Serializable.class;}
        };
        try {
            ConverterManager.getInstance().addInstantConverter(c);
            try {
                ConverterManager.getInstance().getInstantConverter(new DateTime());
                fail();
            } catch (IllegalStateException ex) {
                // Serializable and ReadableInstant both match, so cannot pick
            }
        } finally {
            ConverterManager.getInstance().removeInstantConverter(c);
        }
        assertEquals(6, ConverterManager.getInstance().getInstantConverters().length);
    }