in src/main/java/org/apache/cassandra/distributed/shared/AbstractBuilder.java [72:78]
protected int getDefaultTokenCount() {
String key = "cassandra.dtest.num_tokens";
String value = System.getProperty(key);
if (value == null)
value = System.getenv(key.replace(".", "_").toUpperCase());
return value == null ? 1 : Integer.parseInt(value);
}