diff --git a/test/crossrunner/collect.py b/test/crossrunner/collect.py
new file mode 100644
index 0000000..80a82e7
--- /dev/null
+++ b/test/crossrunner/collect.py
@@ -0,0 +1,136 @@
+#
+# 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.
+#
+
+import platform
+from itertools import product
+
+from crossrunner.util import merge_dict
+
+# Those keys are passed to execution as is.
+# Note that there are keys other than these, namely:
+# delay: After server is started, client start is delayed for the value
+# (seconds).
+# timeout: Test timeout after client is started (seconds).
+# platforms: Supported platforms. Should match platform.system() value.
+# protocols: list of supported protocols
+# transports: list of supported transports
+# sockets: list of supported sockets
+VALID_JSON_KEYS = [
+  'name',  # name of the library, typically a language name
+  'workdir',  # work directory where command is executed
+  'command',  # test command
+  'extra_args',  # args appended to command after other args are appended
+  'join_args',  # whether args should be passed as single concatenated string
+  'env',  # additional environmental variable
+]
+
+DEFAULT_DELAY = 1
+DEFAULT_TIMEOUT = 5
+
+
+def collect_testlibs(config, server_match, client_match):
+  """Collects server/client configurations from library configurations"""
+  def expand_libs(config):
+    for lib in config:
+      sv = lib.pop('server', None)
+      cl = lib.pop('client', None)
+      yield lib, sv, cl
+
+  def yield_testlibs(base_configs, configs, match):
+    for base, conf in zip(base_configs, configs):
+      if conf:
+        if not match or base['name'] in match:
+          platforms = conf.get('platforms') or base.get('platforms')
+          if not platforms or platform.system() in platforms:
+            yield merge_dict(base, conf)
+
+  libs, svs, cls = zip(*expand_libs(config))
+  servers = list(yield_testlibs(libs, svs, server_match))
+  clients = list(yield_testlibs(libs, cls, client_match))
+  return servers, clients
+
+
+def do_collect_tests(servers, clients):
+  def intersection(key, o1, o2):
+    """intersection of two collections.
+    collections are replaced with sets the first time"""
+    def cached_set(o, key):
+      v = o[key]
+      if not isinstance(v, set):
+        v = set(v)
+        o[key] = v
+      return v
+    return cached_set(o1, key) & cached_set(o2, key)
+
+  # each entry can be spec:impl (e.g. binary:accel)
+  def intersect_with_spec(key, o1, o2):
+    # store as set of (spec, impl) tuple
+    def cached_set(o):
+      def to_spec_impl_tuples(values):
+        for v in values:
+          spec, _, impl = v.partition(':')
+          yield spec, impl or spec
+      v = o[key]
+      if not isinstance(v, set):
+        v = set(to_spec_impl_tuples(set(v)))
+        o[key] = v
+      return v
+    for spec1, impl1 in cached_set(o1):
+      for spec2, impl2 in cached_set(o2):
+        if spec1 == spec2:
+          name = impl1 if impl1 == impl2 else '%s-%s' % (impl1, impl2)
+          yield name, impl1, impl2
+
+  def maybe_max(key, o1, o2, default):
+    """maximum of two if present, otherwise defult value"""
+    v1 = o1.get(key)
+    v2 = o2.get(key)
+    return max(v1, v2) if v1 and v2 else v1 or v2 or default
+
+  def filter_with_validkeys(o):
+    ret = {}
+    for key in VALID_JSON_KEYS:
+      if key in o:
+        ret[key] = o[key]
+    return ret
+
+  def merge_metadata(o, **ret):
+    for key in VALID_JSON_KEYS:
+      if key in o:
+        ret[key] = o[key]
+    return ret
+
+  for sv, cl in product(servers, clients):
+    for proto, proto1, proto2 in intersect_with_spec('protocols', sv, cl):
+      for trans, trans1, trans2 in intersect_with_spec('transports', sv, cl):
+        for sock in intersection('sockets', sv, cl):
+          yield {
+            'server': merge_metadata(sv, **{'protocol': proto1, 'transport': trans1}),
+            'client': merge_metadata(cl, **{'protocol': proto2, 'transport': trans2}),
+            'delay': maybe_max('delay', sv, cl, DEFAULT_DELAY),
+            'timeout': maybe_max('timeout', sv, cl, DEFAULT_TIMEOUT),
+            'protocol': proto,
+            'transport': trans,
+            'socket': sock
+          }
+
+
+def collect_tests(tests_dict, server_match, client_match):
+  sv, cl = collect_testlibs(tests_dict, server_match, client_match)
+  return list(do_collect_tests(sv, cl))