diff --git a/build.conf b/build.conf
index fd12a5e..15c5822 100644
--- a/build.conf
+++ b/build.conf
@@ -1120,6 +1120,14 @@
 install = test
 libs = libsvn_test libsvn_subr apriconv apr
 
+[task-test]
+description = Test concurrent tasks
+type = exe
+path = subversion/tests/libsvn_subr
+sources = task-test.c
+install = test
+libs = libsvn_test libsvn_subr apr
+
 [time-test]
 description = Test time functions
 type = exe
@@ -1578,7 +1586,7 @@
        repos-test authz-test dump-load-test
        checksum-test compat-test config-test hashdump-test mergeinfo-test
        opt-test packed-data-test path-test prefix-string-test
-       priority-queue-test root-pools-test stream-test
+       priority-queue-test root-pools-test stream-test task-test
        string-test time-test utf-test bit-array-test filesize-test
        error-test error-code-test cache-test spillbuf-test crypto-test
        revision-test
diff --git a/subversion/tests/libsvn_subr/task-test.c b/subversion/tests/libsvn_subr/task-test.c
new file mode 100644
index 0000000..9c34ee7
--- /dev/null
+++ b/subversion/tests/libsvn_subr/task-test.c
@@ -0,0 +1,253 @@
+
+/*
+ * task-test.c:  a collection of svn_task__* tests
+ *
+ * ====================================================================
+ *    Licensed to the Apache Software Foundation (ASF) under one
+ *    or more contributor license agreements.  See the NOTICE file
+ *    distributed with this work for additional information
+ *    regarding copyright ownership.  The ASF licenses this file
+ *    to you under the Apache License, Version 2.0 (the
+ *    "License"); you may not use this file except in compliance
+ *    with the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing,
+ *    software distributed under the License is distributed on an
+ *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *    KIND, either express or implied.  See the License for the
+ *    specific language governing permissions and limitations
+ *    under the License.
+ * ====================================================================
+ */
+
+/* ====================================================================
+   To add tests, look toward the bottom of this file.
+
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <apr_pools.h>
+
+#include "../svn_test.h"
+
+#include "svn_sorts.h"
+#include "private/svn_atomic.h"
+#include "private/svn_task.h"
+
+static svn_error_t *
+test_null_task(apr_pool_t *pool)
+{
+  SVN_ERR(svn_task__run(1, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+                        pool, pool));
+  SVN_ERR(svn_task__run(2, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+                        pool, pool));
+
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+noop_process_func(void **result,
+                  svn_task__t *task,
+                  void *thread_context,
+                  void *process_baton,
+                  svn_cancel_func_t cancel_func,
+                  void *cancel_baton,
+                  apr_pool_t *result_pool,
+                  apr_pool_t *scratch_pool)
+{
+  *result = NULL;
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+noop_output_func(svn_task__t *task,
+                 void *result,
+                 void *output_baton,
+                 svn_cancel_func_t cancel_func,
+                 void *cancel_baton,
+                 apr_pool_t *result_pool,
+                 apr_pool_t *scratch_pool)
+{
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+noop_thead_context_constructor(void **thread_context,
+                               void *baton,
+                               apr_pool_t *result_pool,
+                               apr_pool_t *scratch_pool)
+{
+  *thread_context = NULL;
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+noop_cancel_func(void *baton)
+{
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+test_noop_task(apr_pool_t *pool)
+{
+  SVN_ERR(svn_task__run(1,
+                        noop_process_func, NULL,
+                        noop_output_func, NULL,
+                        noop_thead_context_constructor, NULL,
+                        noop_cancel_func, NULL, pool, pool));
+  SVN_ERR(svn_task__run(2,
+                        noop_process_func, NULL,
+                        noop_output_func, NULL,
+                        noop_thead_context_constructor, NULL,
+                        noop_cancel_func, NULL, pool, pool));
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+counter_func(void **result,
+             svn_task__t *task,
+             void *thread_context,
+             void *process_baton,
+             svn_cancel_func_t cancel_func,
+             void *cancel_baton,
+             apr_pool_t *result_pool,
+             apr_pool_t *scratch_pool)
+{
+  apr_int64_t value = *(apr_int64_t*)process_baton;
+
+  apr_pool_t *sub_task_pool;
+  apr_int64_t *partial_result;
+  apr_int64_t *partial_baton;
+
+  if (value > 1)
+    {
+      partial_result = apr_palloc(result_pool, sizeof(partial_result));
+      *partial_result = 1;
+      value -= *partial_result;
+
+      sub_task_pool = svn_task__create_process_pool(task);
+
+      partial_baton = apr_palloc(sub_task_pool, sizeof(partial_baton));      
+      *partial_baton = MAX(1, value / 2);
+      value -= *partial_baton;
+
+      SVN_ERR(svn_task__add_similar(task, sub_task_pool, 
+                                    partial_result, partial_baton));
+    }
+
+  if (cancel_func)
+    SVN_ERR(cancel_func(cancel_baton));
+    
+  if (value > 1)
+    {
+      partial_result = apr_palloc(result_pool, sizeof(partial_result));
+      *partial_result = 1;
+      value -= *partial_result;
+
+      sub_task_pool = svn_task__create_process_pool(task);
+
+      partial_baton = apr_palloc(sub_task_pool, sizeof(partial_baton));    
+      *partial_baton = value - 1;
+      value -= *partial_baton;
+
+      SVN_ERR(svn_task__add_similar(task, sub_task_pool,
+                                    partial_result, partial_baton));
+    }
+
+  partial_result = apr_palloc(result_pool, sizeof(partial_result));
+  *partial_result = value;
+  *result = partial_result;
+
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+sum_func(svn_task__t *task,
+         void *result,
+         void *output_baton,
+         svn_cancel_func_t cancel_func,
+         void *cancel_baton,
+         apr_pool_t *result_pool,
+         apr_pool_t *scratch_pool)
+{
+  apr_int64_t *result_p = result;
+  apr_int64_t *output_p = output_baton;
+  
+  if (result_p)
+    *output_p += *result_p;
+
+  if (cancel_func)
+    SVN_ERR(cancel_func(cancel_baton));
+
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+test_counting(apr_pool_t *pool)
+{
+  apr_int64_t start = 1000000;
+  apr_int64_t result = 0;
+  SVN_ERR(svn_task__run(1, counter_func, &start, sum_func, &result,
+                        NULL, NULL, NULL, NULL, pool, pool));
+  SVN_TEST_ASSERT(result == start);
+
+  result = 0;
+  SVN_ERR(svn_task__run(4, counter_func, &start, sum_func, &result,
+                        NULL, NULL, NULL, NULL, pool, pool));
+  SVN_TEST_ASSERT(result == start);
+
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+cancel_at_10k(void *baton)
+{
+  if (*(apr_int64_t*)baton == 10000)
+    return svn_error_create(SVN_ERR_CANCELLED, NULL, NULL);
+
+  return SVN_NO_ERROR;
+}
+
+static svn_error_t *
+test_cancellation(apr_pool_t *pool)
+{
+  apr_int64_t start = 1000000;
+  apr_int64_t result = 0;
+  SVN_TEST_ASSERT_ERROR(svn_task__run(1, counter_func, &start, sum_func, &result,
+                                      NULL, NULL, cancel_at_10k, &result,
+                                      pool, pool),
+                        SVN_ERR_CANCELLED);
+  SVN_TEST_ASSERT(result == 10000);
+
+  result = 0;
+  SVN_TEST_ASSERT_ERROR(svn_task__run(8, counter_func, &start, sum_func, &result,
+                                      NULL, NULL, cancel_at_10k, &result,
+                                      pool, pool),
+                        SVN_ERR_CANCELLED);
+  SVN_TEST_ASSERT(result == 10000);
+  
+  return SVN_NO_ERROR;
+}
+
+/* An array of all test functions */
+
+static int max_threads = 1;
+
+static struct svn_test_descriptor_t test_funcs[] =
+  {
+    SVN_TEST_NULL,
+    SVN_TEST_PASS2(test_null_task,
+                   "null-task"),
+    SVN_TEST_PASS2(test_noop_task,
+                   "no-op task"),
+    SVN_TEST_PASS2(test_counting,
+                   "concurrent counting"),
+    SVN_TEST_PASS2(test_cancellation,
+                   "cancelling tasks"),
+    SVN_TEST_NULL
+  };
+
+SVN_TEST_MAIN