I did a similar thing a few months ago, and it turned out this simple format was enough for Hudson to accept it as a test protocol:

<testsuite tests="3">    <testcase classname="foo1" name="ASuccessfulTest"/>    <testcase classname="foo2" name="AnotherSuccessfulTest"/>    <testcase classname="foo3" name="AFailingTest">        <failure type="NotEnoughFoo"> details about failure </failure>    </testcase></testsuite>

This question has answers with more details: Spec. for JUnit XML Output

I just grabbed the junit-4.xsd that others have linked to and used a tool named XMLSpear to convert the schema to a blank XML file with the options shown below. This is the (slightly cleaned up) result:

<?xml version="1.0" encoding="UTF-8"?><testsuites disabled="" errors="" failures="" name="" tests="" time="">    <testsuite disabled="" errors="" failures="" hostname="" id=""               name="" package="" skipped="" tests="" time="" timestamp="">        <properties>            <property name="" value=""/>        </properties>        <testcase assertions="" classname="" name="" status="" time="">            <skipped/>            <error message="" type=""/>            <failure message="" type=""/>            <system-out/>            <system-err/>        </testcase>        <system-out/>        <system-err/>    </testsuite></testsuites>

Some of these items can occur multiple times:

• There can only be one testsuites element, since that’s how XML works, but there can be multiple testsuite elements within the testsuites element.
• Each properties element can have multiple property children.
• Each testsuite element can have multiple testcase children.
• Each testcase element can have multiple error, failure, system-out, or system-err children.

The top answer of the question Anders Lindahl refers to an xsd file.

Personally I found this xsd file also very useful (I don't remember how I found that one). It looks a bit less intimidating, and as far as I used it, all the elements and attributes seem to be recognized by Jenkins (v1.451)

One thing though: when adding multiple <failure ... elements, only one was retained in Jenkins. When creating the xml file, I now concatenate all the failures in one.

Update 2016-11 The link is broken now. A better alternative is this page from cubic.org: JUnit XML reporting file format, where a nice effort has been taken to provide a sensible documented example. Example and xsd are copied below, but their page looks waay nicer.

sample JUnit XML file

<?xml version="1.0" encoding="UTF-8"?><!-- a description of the JUnit XML format and how Jenkins parses it. See also junit.xsd --><!-- if only a single testsuite element is present, the testsuites     element can be omitted. All attributes are optional. --><testsuites disabled="" <!-- total number of disabled tests from all testsuites. -->            errors=""   <!-- total number of tests with error result from all testsuites. -->            failures="" <!-- total number of failed tests from all testsuites. -->            name=""            tests=""    <!-- total number of successful tests from all testsuites. -->            time=""     <!-- time in seconds to execute all test suites. -->        >  <!-- testsuite can appear multiple times, if contained in a testsuites element.       It can also be the root element. -->  <testsuite name=""      <!-- Full (class) name of the test for non-aggregated testsuite documents.                               Class name without the package for aggregated testsuites documents. Required -->         tests=""     <!-- The total number of tests in the suite, required. -->         disabled=""  <!-- the total number of disabled tests in the suite. optional -->             errors=""    <!-- The total number of tests in the suite that errored. An errored test is one that had an unanticipated problem,                               for example an unchecked throwable; or a problem with the implementation of the test. optional -->             failures=""  <!-- The total number of tests in the suite that failed. A failure is a test which the code has explicitly failed                               by using the mechanisms for that purpose. e.g., via an assertEquals. optional -->             hostname=""  <!-- Host on which the tests were executed. 'localhost' should be used if the hostname cannot be determined. optional -->         id=""        <!-- Starts at 0 for the first testsuite and is incremented by 1 for each following testsuite -->         package=""   <!-- Derived from testsuite/@name in the non-aggregated documents. optional -->         skipped=""   <!-- The total number of skipped tests. optional -->         time=""      <!-- Time taken (in seconds) to execute the tests in the suite. optional -->         timestamp="" <!-- when the test was executed in ISO 8601 format (2014-01-21T16:17:18). Timezone may not be specified. optional -->         >    <!-- Properties (e.g., environment settings) set during test     execution. The properties element can appear 0 or once. -->    <properties>      <!-- property can appear multiple times. The name and value attributres are required. -->      <property name="" value=""/>    </properties>    <!-- testcase can appear multiple times, see /testsuites/testsuite@tests -->    <testcase name=""       <!-- Name of the test method, required. -->          assertions="" <!-- number of assertions in the test case. optional -->          classname=""  <!-- Full class name for the class the test method is in. required -->          status=""          time=""       <!-- Time taken (in seconds) to execute the test. optional -->          >      <!-- If the test was not executed or failed, you can specify one           the skipped, error or failure elements. -->      <!-- skipped can appear 0 or once. optional -->      <skipped/>      <!-- Indicates that the test errored. An errored test is one           that had an unanticipated problem. For example an unchecked           throwable or a problem with the implementation of the           test. Contains as a text node relevant data for the error,           for example a stack trace. optional -->      <error message="" <!-- The error message. e.g., if a java exception is thrown, the return value of getMessage() -->         type=""    <!-- The type of error that occured. e.g., if a java execption is thrown the full class name of the exception. -->         ></error>      <!-- Indicates that the test failed. A failure is a test which       the code has explicitly failed by using the mechanisms for       that purpose. For example via an assertEquals. Contains as       a text node relevant data for the failure, e.g., a stack       trace. optional -->      <failure message="" <!-- The message specified in the assert. -->           type=""    <!-- The type of the assert. -->           ></failure>      <!-- Data that was written to standard out while the test was executed. optional -->      <system-out></system-out>      <!-- Data that was written to standard error while the test was executed. optional -->      <system-err></system-err>    </testcase>    <!-- Data that was written to standard out while the test suite was executed. optional -->    <system-out></system-out>    <!-- Data that was written to standard error while the test suite was executed. optional -->    <system-err></system-err>  </testsuite></testsuites>

JUnit XSD file

<?xml version="1.0" encoding="UTF-8" ?><!-- from https://svn.jenkins-ci.org/trunk/hudson/dtkit/dtkit-format/dtkit-junit-model/src/main/resources/com/thalesgroup/dtkit/junit/model/xsd/junit-4.xsd --><xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">    <xs:element name="failure">        <xs:complexType mixed="true">            <xs:attribute name="type" type="xs:string" use="optional"/>            <xs:attribute name="message" type="xs:string" use="optional"/>        </xs:complexType>    </xs:element>    <xs:element name="error">        <xs:complexType mixed="true">            <xs:attribute name="type" type="xs:string" use="optional"/>            <xs:attribute name="message" type="xs:string" use="optional"/>        </xs:complexType>    </xs:element>    <xs:element name="properties">        <xs:complexType>            <xs:sequence>                <xs:element ref="property" maxOccurs="unbounded"/>            </xs:sequence>        </xs:complexType>    </xs:element>    <xs:element name="property">        <xs:complexType>            <xs:attribute name="name" type="xs:string" use="required"/>            <xs:attribute name="value" type="xs:string" use="required"/>        </xs:complexType>    </xs:element>    <xs:element name="skipped" type="xs:string"/>    <xs:element name="system-err" type="xs:string"/>    <xs:element name="system-out" type="xs:string"/>    <xs:element name="testcase">        <xs:complexType>            <xs:sequence>                <xs:element ref="skipped" minOccurs="0" maxOccurs="1"/>                <xs:element ref="error" minOccurs="0" maxOccurs="unbounded"/>                <xs:element ref="failure" minOccurs="0" maxOccurs="unbounded"/>                <xs:element ref="system-out" minOccurs="0" maxOccurs="unbounded"/>                <xs:element ref="system-err" minOccurs="0" maxOccurs="unbounded"/>            </xs:sequence>            <xs:attribute name="name" type="xs:string" use="required"/>            <xs:attribute name="assertions" type="xs:string" use="optional"/>            <xs:attribute name="time" type="xs:string" use="optional"/>            <xs:attribute name="classname" type="xs:string" use="optional"/>            <xs:attribute name="status" type="xs:string" use="optional"/>        </xs:complexType>    </xs:element>    <xs:element name="testsuite">        <xs:complexType>            <xs:sequence>                <xs:element ref="properties" minOccurs="0" maxOccurs="1"/>                <xs:element ref="testcase" minOccurs="0" maxOccurs="unbounded"/>                <xs:element ref="system-out" minOccurs="0" maxOccurs="1"/>                <xs:element ref="system-err" minOccurs="0" maxOccurs="1"/>            </xs:sequence>            <xs:attribute name="name" type="xs:string" use="required"/>            <xs:attribute name="tests" type="xs:string" use="required"/>            <xs:attribute name="failures" type="xs:string" use="optional"/>            <xs:attribute name="errors" type="xs:string" use="optional"/>            <xs:attribute name="time" type="xs:string" use="optional"/>            <xs:attribute name="disabled" type="xs:string" use="optional"/>            <xs:attribute name="skipped" type="xs:string" use="optional"/>            <xs:attribute name="timestamp" type="xs:string" use="optional"/>            <xs:attribute name="hostname" type="xs:string" use="optional"/>            <xs:attribute name="id" type="xs:string" use="optional"/>            <xs:attribute name="package" type="xs:string" use="optional"/>        </xs:complexType>    </xs:element>    <xs:element name="testsuites">        <xs:complexType>            <xs:sequence>                <xs:element ref="testsuite" minOccurs="0" maxOccurs="unbounded"/>            </xs:sequence>            <xs:attribute name="name" type="xs:string" use="optional"/>            <xs:attribute name="time" type="xs:string" use="optional"/>            <xs:attribute name="tests" type="xs:string" use="optional"/>            <xs:attribute name="failures" type="xs:string" use="optional"/>            <xs:attribute name="disabled" type="xs:string" use="optional"/>            <xs:attribute name="errors" type="xs:string" use="optional"/>        </xs:complexType>    </xs:element></xs:schema>