private static String param(String propertyName, String prompt, String defaultValue) throws Exception {
        if (System.getProperty(propertyName) != null) {
            return System.getProperty(propertyName);
        }
        System.out.print(prompt + " [" + defaultValue + "]: ");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String input = br.readLine();
        if (input == null || input.trim().isEmpty()) {
            input = defaultValue;
        }

        System.setProperty(propertyName, input);
        return input;
    }
Gets a param value, updates the system properties if necessary.
@param propertyName
@param prompt
@param defaultValue
@throws Exception
test/suite/src/main/java/io/apiman/test/suite/FullTestSuite.java