./gradlew -q text

For e.g. 10 days:

./gradlew -q text --args 10

You should make sure the gradle commands shown above work when you execute them in a terminal before trying to use TextTest (see below).

There are instructions in the TextTest Readme for setting up TextTest. What's unusual for the Java version is there are two executables listed in config.gr for Java. The first uses Gradle wrapped in a python script. Uncomment these lines to use it:

executable:${TEXTTEST_HOME}/Java/texttest_rig.py
interpreter:python

The other relies on your CLASSPATH being set correctly in environment.gr. Uncomment these lines to use it instead:

executable:com.gildedrose.TexttestFixture
interpreter:java