restygwt/src/main/java/org/fusesource/restygwt/client/Method.java
public Method expect(int... statuses) {
        if (statuses.length == 1 && statuses[0] < 0) {
            anyStatus = true;
        } else {
            anyStatus = false;
            expectedStatuses.clear();
            for (int status : statuses) {
                expectedStatuses.add(status);
            }
        }
        return this;
    }
public Method expect(int... statuses) {
        if (statuses.length == 1 && statuses[0] < 0) {
            anyStatus = true;
        } else {
            anyStatus = false;
            expectedStatuses.clear();
            for (int status : statuses) {
                expectedStatuses.add(status);
            }
        }
        return this;
    }
sets the expected response status code.  If the response status code does not match
any of the values specified then the request is considered to have failed.  Defaults to accepting
200,201,204. If set to -1 then any status code is considered a success.