I checked out the source code from http://svn.apache.org/repos/asf/ant/core/tags/ANT_165/ and tried to run its testcases on winXP. The result is posted as follows,

How to run ant test on harmony jdk

Download source code.
copy tools.jar and javac.exe to the corresponding locationg of HDK
modify the build.xml to
- set the property test.haltonfailure to "no".
- add the tools.jar to classpath for testing javac task.
- fork a harmony jvm when run junit task.
- change the result format from plain to xml.
- add a target for generating html report.
set JAVA_HOME to HDK
run test RI5.0\bin\java -cp $ANT_HOME\lib\ant-launcher.jar org.apache.tools.ant.launch.Launcher test

Results, Click the number for detail

org.apache.tools.ant.AntClassLoaderDelegationTest@testFindResources	RI may fail too, caused by duplicate lib
org.apache.tools.ant.LoaderRefTest@testBadRef	Javac Related
org.apache.tools.ant.taskdefs.AvailableTest@test21	JDK path
org.apache.tools.ant.taskdefs.ExecuteWatchdogTest@testFailed	return value of java.exe
org.apache.tools.ant.taskdefs.JavaTest@testExceptingFoeFork	JDK path
org.apache.tools.ant.taskdefs.JavaTest@testExceptingFork	different log message
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testEmptySource	BuildException
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testNoSource	BuildException
org.apache.tools.ant.types.AssertionsTest@testClassname	BuildException
org.apache.tools.ant.types.AssertionsTest@testMultipleAssertions	BuildException
org.apache.tools.ant.types.AssertionsTest@testOverride	BuildException
org.apache.tools.ant.types.AssertionsTest@testPackage	BuildException
org.apache.tools.ant.types.AssertionsTest@testReferenceAbuse	BuildException
org.apache.tools.ant.util.ClasspathUtilsTest@testOnlyOneInstance	should be only one default.properties in classpath
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="62479438-db2e-4e89-82db-bb0d1b02d13a"><ac:plain-text-body><![CDATA[	org.apache.tools.ant.util.JavaEnvUtilsTest@testGetExecutableWindows	null expected:<[]javac.exe> but was:<[C:\workspace\harmony\deploy\jdk\jre\bin ]javac.exe>	]]></ac:plain-text-body></ac:structured-macro>

org.apache.tools.ant.TaskContainerTest@testTaskdef	Javac Related
org.apache.tools.ant.taskdefs.AvailableTest@test24	Javac Related
org.apache.tools.ant.taskdefs.FixCrLfTest@testEncoding	UnicodeBig
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testCache	Javac Related
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testClosure	Javac Related
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testDirect	Javac Related
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testInner	Javac Related
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testInnerClosure	Javac Related
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testInnerInner	Javac Related
org.apache.tools.ant.taskdefs.optional.depend.DependTest@testNonPublic	Javac Related
org.apache.tools.ant.taskdefs.SignJarTest@testURLKeystoreHTTP	RI fail
org.apache.tools.ant.taskdefs.TouchTest@testBadPattern	different message in Exception
org.apache.tools.ant.taskdefs.UnzipTest@testEncoding	UnicodeBig
org.apache.tools.ant.types.AssertionsTest@testDisable	Javac Related
org.apache.tools.ant.types.AssertionsTest@testEmptyAssertions	Javac Related
org.apache.tools.ant.types.AssertionsTest@testNofork	Javac Related
org.apache.tools.ant.types.AssertionsTest@testOverride2	Javac Related