build.xml

<project name="junit-example">
  <property name="main.build.dir" value="build/main"/>
  <property name="main.src.dir" value="src"/>
  <property name="test.build.dir" value="build/test"/>
  <property name="test.src.dir" value="tests/kakuro"/>

  <path id="classpath.test">
    <pathelement location="lib/junit-4.12.0.jar"/>
    <pathelement location="lib/org.hamcrest.core_1.3.0.jar"/>
    <pathelement location="lib/gson-2.8.6.jar"/>
    <pathelement location="lib/sqlite-jdbc-3.30.1.jar"/>
    <pathelement location="${main.build.dir}"/>
  </path>

  <target name="compile">
    <mkdir dir="${main.build.dir}"/>
    <javac srcdir="${main.src.dir}" destdir="${main.build.dir}" includeantruntime="false">
        <classpath refid="classpath.test"/>
    </javac>
  </target>

  <target name="test-compile" depends="compile">
    <mkdir dir="${test.build.dir}"/>
    <javac srcdir="${test.src.dir}" destdir="${test.build.dir}" includeantruntime="false">
        <classpath refid="classpath.test"/>
    </javac>
  </target>

  <target name="test" depends="test-compile">
    <junit printsummary="on" haltonfailure="yes" fork="true">
        <classpath>
          <path refid="classpath.test"/>
          <pathelement location="${test.build.dir}"/>
        </classpath>
        <formatter type="brief" usefile="false" />
        <batchtest>
            <fileset dir="${test.build.dir}" includes="**/*Test*" />
        </batchtest>
    </junit>
  </target>
</project>