JUnit tests failed executed as an ant target

I am trying to get code coverage using Cobertura plugin for Jenkins so I instrument, run tests and then coverage report in my build.xml as follow

<?xml version="1.0" encoding="UTF-8"?>
<project name="CoberturaAndJenkins" default="default" basedir=".">
    <description>Builds, tests, and runs the project CoberturaAndJenkins.</description>
    <import file="nbproject/build-impl.xml"/>

    <property name="lib.dir" value="lib/" />
    <property name="junit.file" value="junit-4.11.jar" />
    <property name="cobertura.dir" value="${lib.dir}/cobertura/" />
    <property name="instrumented.dir" value="/var/lib/jenkins/workspace/CoberturaAndJenkins/instrumented/" />
    <property name="coveragereport.dir" value="build/cobertura/" />
    <property name="classes.dir" value="/var/lib/jenkins/workspace/CoberturaAndJenkins/build/classes/" />
    <property name="reports.xml.dir" value="build/test/results/" /> 

    <!-- Modules that build -->
    <property name="src.dir" value="src/" />
    <property name="test.dir" value="test/" />


    <!-- Define the Cobertura Ant tasks -->
    <path id="cobertura.classpath">
        <fileset dir="${cobertura.dir}">
            <include name="cobertura-2.0.3.jar" />
            <include name="lib/**/*.jar" />
        </fileset>
        <fileset dir="${lib.dir}" >
            <include name="${junit.file}" />
        </fileset>
    </path>

    <taskdef classpathref="cobertura.classpath" resource="tasks.properties" />

    <path id="test.classpath">
        <path refid="cobertura.classpath" />
        <pathelement location="${bin}" />
        <pathelement location="${instrumented.dir}"/>
        <pathelement location="${classes.dir}" />
    </path>

    <!--============= Instrument the classes that JUnit will be testing =============-->
    <target name="instrument">
        <delete file="cobertura.ser"/>
        <delete dir="${instrumented.dir}" />
        <cobertura-instrument todir="${instrumented.dir}" datafile="cobertura.ser" >
            <fileset dir="${classes.dir}">
                <include name="**/*.class" />
                <exclude name="**/*Test.class" />
            </fileset>
        </cobertura-instrument>
    </target>

    <!--======================= JUNIT =======================-->

   <property name="basedir" value="./" />
    <target name="module-test" depends="instrument"> 
        <echo level="info" message="Running test cases..." />

        <junit dir="${basedir}" showoutput="yes" fork="yes" printsummary="yes" failureProperty="test.failed">
            <!--Specify the name of the coverage data file to use.
                    The value specified below is the default.-->
            <sysproperty key="net.sourceforge.cobertura.datafile" file="cobertura.ser" />

            <classpath refid="test.classpath" />

            <formatter type="xml" />
            <batchtest fork="yes" todir="${reports.xml.dir}">
                <fileset dir="${test.dir}">
                    <include name="**/*Test.java" />
                </fileset>
            </batchtest>
        </junit>
    </target>


    <!--===================== COBERTURA REPORT ================================-->
    <target name="coverage-report" depends="module-test">
        <cobertura-report format="xml" destdir="${coveragereport.dir}" datafile="cobertura.ser" >
            <fileset dir="${src.dir}">
                <include name="**/*.java" />
            </fileset>
        </cobertura-report>
        <cobertura-report format="html" destdir="${coveragereport.dir}" datafile="cobertura.ser" >
            <fileset dir="${src.dir}">
                <include name="**/*.java" />
            </fileset>
        </cobertura-report>
    </target>
    <!--================== END OF COBERTURA REPORT ============================-->

</project>

The thing is that when it tries to run the unit tests (which I can run using ant test) it keeps saying

module-test:
Running test cases...
Running coberturaandjenkins.CoberturaAndJenkinsTest
Tests run: 1, Failures: 0, Errors: 1, Time elapsed: 0 sec
Test coberturaandjenkins.CoberturaAndJenkinsTest FAILED

I have changed, re-changed, re-re-changed the build.xml without any luck for days. I can't get it work. Please, I'd appreciate any help here. It's the first time I'm using ant (and Cobertura)

Thanks for all your answers guys. After further investigation, I figured out how to make it work. I had to completely re-write the build.xml. Here it is:

<property file="build.properties" />

<path id="cobertura.classpath">
    <fileset dir="${cobertura.dir}">
        <include name="**/*.jar" />
    </fileset>
</path>

<taskdef classpathref="cobertura.classpath" resource="tasks.properties"/>

<target name="init">
    <mkdir dir="${classes.dir}" />
    <mkdir dir="${instrumented.dir}" />
    <mkdir dir="${reports.xml.dir}" />
    <mkdir dir="${reports.html.dir}" />
    <mkdir dir="${coverage.xml.dir}" />
    <mkdir dir="${coverage.summaryxml.dir}" />
    <mkdir dir="${coverage.html.dir}" />
</target>

<target name="compile" depends="init">
    <javac srcdir="${src.dir}" destdir="${classes.dir}" debug="yes" includeantruntime="false">
        <classpath refid="cobertura.classpath" />
    </javac>
    <javac srcdir="${test.src.dir}" destdir="${classes.dir}" debug="yes" includeantruntime="false">
        <classpath refid="cobertura.classpath" />
    </javac>
</target>

<target name="instrument" depends="init,compile">
    <!--
            Remove the coverage data file and any old instrumentation.
    -->
    <delete file="cobertura.ser"/>
    <delete dir="${instrumented.dir}" />

    <!--
            Instrument the application classes, writing the
            instrumented classes into ${build.instrumented.dir}.
    -->
    <cobertura-instrument todir="${instrumented.dir}">
        <!--
                The following line causes instrument to ignore any
                source line containing a reference to log4j, for the
                purposes of coverage reporting.
        -->
        <ignore regex="org.apache.log4j.*" />

        <fileset dir="${classes.dir}">
            <!--
                    Instrument all the application classes, but
                    don't instrument the test classes.
            -->
            <include name="**/*.class" />
            <exclude name="**/*Test.class" />
        </fileset>
    </cobertura-instrument>
</target>

<target name="test" depends="init,compile">
    <junit fork="yes" dir="${basedir}" failureProperty="test.failed">
        <!--
                Note the classpath order: instrumented classes are before the
                original (uninstrumented) classes.  This is important.
        -->
        <classpath location="${instrumented.dir}" />
        <classpath location="${classes.dir}" />

        <!--
                The instrumented classes reference classes used by the
                Cobertura runtime, so Cobertura and its dependencies
                must be on your classpath.
        -->
        <classpath refid="cobertura.classpath" />

        <formatter type="xml" />
        <test name="${testcase}" todir="${reports.xml.dir}" if="testcase" />
        <batchtest todir="${reports.xml.dir}" unless="testcase">
            <fileset dir="${test.src.dir}">
                <include name="**/*Test.java" />
            </fileset>
        </batchtest>
    </junit>

    <!-- JUnit Report in HTML -->
    <junitreport todir="${reports.xml.dir}">
        <fileset dir="${reports.xml.dir}">
            <include name="TEST-*.xml" />
        </fileset>
        <report format="frames" todir="${reports.html.dir}" />
    </junitreport>

</target>

<target name="coverage-check">
    <cobertura-check branchrate="34" totallinerate="100" />
</target>

<target name="coverage-report">
    <!--
            Generate an XML file containing the coverage data using
            the "srcdir" attribute.
    -->
    <cobertura-report srcdir="${src.dir}" destdir="${coverage.xml.dir}" format="xml" />
</target>

<target name="summary-coverage-report">
    <!--
            Generate an summary XML file containing the coverage data using
            the "srcdir" attribute.
    -->
    <cobertura-report srcdir="${src.dir}" destdir="${coverage.summaryxml.dir}" format="summaryXml" />
</target>

<target name="alternate-coverage-report">
    <!--
            Generate a series of HTML files containing the coverage
            data in a user-readable form using nested source filesets.
    -->
    <cobertura-report destdir="${coverage.html.dir}">
        <fileset dir="${src.dir}">
            <include name="**/*.java"/>
        </fileset>
    </cobertura-report>
</target>

<target name="clean" description="Remove all files created by the build/test process.">
    <delete dir="${classes.dir}" />
    <delete dir="${instrumented.dir}" />
    <delete dir="${reports.dir}" />
    <delete file="cobertura.log" />
    <delete file="cobertura.ser" />
</target>

<target name="coverage" depends="compile,instrument,test,coverage-report,summary-coverage-report,alternate-coverage-report" description="Compile, instrument ourself, run the tests and generate JUnit and coverage reports."/>

The properties definition are in the build.properties file referenced at the beginning