Run an org's namespace tests from SOAP (untested). NOTE: This only works with v30.0. To work with v29.0, you must use the Apex API (wsdl).

RunNSTest.java

SoapConnection conn = // Get the tooling soap connection;

String namespace = "";
QueryResult qr = conn.query("SELECT Id, SymbolTable FROM ApexClass WHERE NamespacePrefix = '"+namespace+"'");

List<String> ids = new ArrayList<String>();

SObject[] classes = qr.getRecords();
for (int i = 0; i < classes.length; i++) {
    ApexClass rec = (ApexClass)classes[i];
    SymbolTable st = rec.getSymbolTable();
    String[] mods = st.getTableDeclaration().getModifiers();
    int modLen = mods.length;
    for (int modIndex = 0; modIndex < mods.length; modIndex++) {
        if (mods[modIndex].equals("TEST")) {
            ids.add(rec.getId());
        }
    }
}


if (ids.size() > 0) {
    RunTestsRequest rtr = new RunTestsRequest();
    String[] idsArray = ids.toArray(new String[]{});
    
    rtr.setClasses(idsArray);
    RunTestsResult result = conn.runTests(rtr);
    // Do what you need to do with the results
    
    //If you want to get the results in setup or the dev console as well, do the following:
    //NOTE: You need Apache Commons in your path to use the following line.
    //conn.runTestsAsynchronous(StringUtil.join(",", idsArray););
}