Enable split code generation

To support magical internal build processes, the pb2 files need to be
split into pure-proto and gRPC parts. This performs that split and
further fixes bad module names in the test harness that interfered with
the intended test implementation.

An unfortunate side effect, due to limitations of protoc and holdover
behavior we must support in major version 1.x, is that trash files are
generated in split generation. This shouldn't be a problem in normal
protoc plugin use.

13 files changed, 812 insertions, 186 deletions

diff --git a/src/compiler/python_generator.cc b/src/compiler/python_generator.cc
index 6830f49931..270291ac33 100644
--- a/src/compiler/python_generator.cc
+++ b/src/compiler/python_generator.cc
@@ -35,6 +35,8 @@
 #include <cassert>
 #include <cctype>
 #include <cstring>
+#include <fstream>
+#include <iostream>
 #include <map>
 #include <memory>
 #include <ostream>
@@ -66,66 +68,7 @@ using std::vector;
 
 namespace grpc_python_generator {
 
-GeneratorConfiguration::GeneratorConfiguration()
-    : grpc_package_root("grpc"), beta_package_root("grpc.beta") {}
-
-PythonGrpcGenerator::PythonGrpcGenerator(const GeneratorConfiguration& config)
-    : config_(config) {}
-
-PythonGrpcGenerator::~PythonGrpcGenerator() {}
-
-bool PythonGrpcGenerator::Generate(const FileDescriptor* file,
-                                   const grpc::string& parameter,
-                                   GeneratorContext* context,
-                                   grpc::string* error) const {
-  // Get output file name.
-  grpc::string file_name;
-  static const int proto_suffix_length = strlen(".proto");
-  if (file->name().size() > static_cast<size_t>(proto_suffix_length) &&
-      file->name().find_last_of(".proto") == file->name().size() - 1) {
-    file_name =
-        file->name().substr(0, file->name().size() - proto_suffix_length) +
-        "_pb2.py";
-  } else {
-    *error = "Invalid proto file name. Proto file must end with .proto";
-    return false;
-  }
-
-  std::unique_ptr<ZeroCopyOutputStream> output(
-      context->OpenForInsert(file_name, "module_scope"));
-  CodedOutputStream coded_out(output.get());
-  bool success = false;
-  grpc::string code = "";
-  tie(success, code) = grpc_python_generator::GetServices(file, config_);
-  if (success) {
-    coded_out.WriteRaw(code.data(), code.size());
-    return true;
-  } else {
-    return false;
-  }
-}
-
 namespace {
-//////////////////////////////////
-// BEGIN FORMATTING BOILERPLATE //
-//////////////////////////////////
-
-// Converts an initializer list of the form { key0, value0, key1, value1, ... }
-// into a map of key* to value*. Is merely a readability helper for later code.
-map<grpc::string, grpc::string> ListToDict(
-    const initializer_list<grpc::string>& values) {
-  assert(values.size() % 2 == 0);
-  map<grpc::string, grpc::string> value_map;
-  auto value_iter = values.begin();
-  for (unsigned i = 0; i < values.size() / 2; ++i) {
-    grpc::string key = *value_iter;
-    ++value_iter;
-    grpc::string value = *value_iter;
-    value_map[key] = value;
-    ++value_iter;
-  }
-  return value_map;
-}
 
 // Provides RAII indentation handling. Use as:
 // {
@@ -146,10 +89,6 @@ class IndentScope {
   Printer* printer_;
 };
 
-////////////////////////////////
-// END FORMATTING BOILERPLATE //
-////////////////////////////////
-
 // TODO(https://github.com/google/protobuf/issues/888):
 // Export `ModuleName` from protobuf's
 // `src/google/protobuf/compiler/python/python_generator.cc` file.
@@ -173,9 +112,61 @@ grpc::string ModuleAlias(const grpc::string& filename) {
   return module_name;
 }
 
-bool GetModuleAndMessagePath(const Descriptor* type,
-                             const ServiceDescriptor* service,
-                             grpc::string* out) {
+// Tucks all generator state in an anonymous namespace away from
+// PythonGrpcGenerator and the header file, mostly to encourage future changes
+// to not require updates to the grpcio-tools C++ code part. Assumes that it is
+// only ever used from a single thread.
+struct PrivateGenerator {
+  const GeneratorConfiguration& config;
+  const FileDescriptor *file;
+
+  bool generate_in_pb2_grpc;
+
+  Printer *out;
+
+  PrivateGenerator(const GeneratorConfiguration& config,
+                   const FileDescriptor *file);
+
+  std::pair<bool, grpc::string> GetGrpcServices();
+
+ private:
+  bool PrintPreamble();
+  bool PrintBetaPreamble();
+  bool PrintGAServices();
+  bool PrintBetaServices();
+
+  bool PrintAddServicerToServer(
+    const grpc::string& package_qualified_service_name,
+    const ServiceDescriptor* service);
+  bool PrintServicer(const ServiceDescriptor* service);
+  bool PrintStub(const grpc::string& package_qualified_service_name,
+                 const ServiceDescriptor* service);
+
+  bool PrintBetaServicer(const ServiceDescriptor* service);
+  bool PrintBetaServerFactory(const grpc::string& package_qualified_service_name,
+                              const ServiceDescriptor* service);
+  bool PrintBetaStub(const ServiceDescriptor* service);
+  bool PrintBetaStubFactory(
+      const grpc::string& package_qualified_service_name,
+      const ServiceDescriptor* service);
+
+  // Get all comments (leading, leading_detached, trailing) and print them as a
+  // docstring. Any leading space of a line will be removed, but the line
+  // wrapping will not be changed.
+  template <typename DescriptorType>
+  void PrintAllComments(const DescriptorType* descriptor);
+
+  bool GetModuleAndMessagePath(const Descriptor* type,
+                               grpc::string* out);
+};
+
+
+PrivateGenerator::PrivateGenerator(const GeneratorConfiguration& config,
+                                   const FileDescriptor *file)
+  : config(config), file(file) {}
+
+bool PrivateGenerator::GetModuleAndMessagePath(const Descriptor* type,
+                                               grpc::string* out) {
   const Descriptor* path_elem_type = type;
   vector<const Descriptor*> message_path;
   do {
@@ -188,9 +179,13 @@ bool GetModuleAndMessagePath(const Descriptor* type,
         file_name.find_last_of(".proto") == file_name.size() - 1)) {
     return false;
   }
-  grpc::string service_file_name = service->file()->name();
-  grpc::string module =
-      service_file_name == file_name ? "" : ModuleAlias(file_name) + ".";
+  grpc::string generator_file_name = file->name();
+  grpc::string module;
+  if (generator_file_name != file_name || generate_in_pb2_grpc) {
+    module = ModuleAlias(file_name) + ".";
+  } else {
+    module = "";
+  }
   grpc::string message_type;
   for (auto path_iter = message_path.rbegin(); path_iter != message_path.rend();
        ++path_iter) {
@@ -202,33 +197,30 @@ bool GetModuleAndMessagePath(const Descriptor* type,
   return true;
 }
 
-// Get all comments (leading, leading_detached, trailing) and print them as a
-// docstring. Any leading space of a line will be removed, but the line wrapping
-// will not be changed.
 template <typename DescriptorType>
-static void PrintAllComments(const DescriptorType* desc, Printer* printer) {
-  std::vector<grpc::string> comments;
-  grpc_generator::GetComment(desc, grpc_generator::COMMENTTYPE_LEADING_DETACHED,
+void PrivateGenerator::PrintAllComments(const DescriptorType* descriptor) {
+  vector<grpc::string> comments;
+  grpc_generator::GetComment(descriptor, grpc_generator::COMMENTTYPE_LEADING_DETACHED,
                              &comments);
-  grpc_generator::GetComment(desc, grpc_generator::COMMENTTYPE_LEADING,
+  grpc_generator::GetComment(descriptor, grpc_generator::COMMENTTYPE_LEADING,
                              &comments);
-  grpc_generator::GetComment(desc, grpc_generator::COMMENTTYPE_TRAILING,
+  grpc_generator::GetComment(descriptor, grpc_generator::COMMENTTYPE_TRAILING,
                              &comments);
   if (comments.empty()) {
     return;
   }
-  printer->Print("\"\"\"");
+  out->Print("\"\"\"");
   for (auto it = comments.begin(); it != comments.end(); ++it) {
     size_t start_pos = it->find_first_not_of(' ');
     if (start_pos != grpc::string::npos) {
-      printer->Print(it->c_str() + start_pos);
+      out->Print(it->c_str() + start_pos);
     }
-    printer->Print("\n");
+    out->Print("\n");
   }
-  printer->Print("\"\"\"\n");
+  out->Print("\"\"\"\n");
 }
 
-bool PrintBetaServicer(const ServiceDescriptor* service, Printer* out) {
+bool PrivateGenerator::PrintBetaServicer(const ServiceDescriptor* service) {
   out->Print("\n\n");
   out->Print("class Beta$Service$Servicer(object):\n", "Service",
              service->name());
@@ -241,7 +233,7 @@ bool PrintBetaServicer(const ServiceDescriptor* service, Printer* out) {
         "generated\n"
         "only to ease transition from grpcio<0.15.0 to "
         "grpcio>=0.15.0.\"\"\"\n");
-    PrintAllComments(service, out);
+    PrintAllComments(service);
     for (int i = 0; i < service->method_count(); ++i) {
       auto meth = service->method(i);
       grpc::string arg_name =
@@ -250,7 +242,7 @@ bool PrintBetaServicer(const ServiceDescriptor* service, Printer* out) {
                  meth->name(), "ArgName", arg_name);
       {
         IndentScope raii_method_indent(out);
-        PrintAllComments(meth, out);
+        PrintAllComments(meth);
         out->Print("context.code(beta_interfaces.StatusCode.UNIMPLEMENTED)\n");
       }
     }
@@ -258,7 +250,7 @@ bool PrintBetaServicer(const ServiceDescriptor* service, Printer* out) {
   return true;
 }
 
-bool PrintBetaStub(const ServiceDescriptor* service, Printer* out) {
+bool PrivateGenerator::PrintBetaStub(const ServiceDescriptor* service) {
   out->Print("\n\n");
   out->Print("class Beta$Service$Stub(object):\n", "Service", service->name());
   {
@@ -270,18 +262,20 @@ bool PrintBetaStub(const ServiceDescriptor* service, Printer* out) {
         "generated\n"
         "only to ease transition from grpcio<0.15.0 to "
         "grpcio>=0.15.0.\"\"\"\n");
-    PrintAllComments(service, out);
+    PrintAllComments(service);
     for (int i = 0; i < service->method_count(); ++i) {
       const MethodDescriptor* meth = service->method(i);
       grpc::string arg_name =
           meth->client_streaming() ? "request_iterator" : "request";
-      auto methdict = ListToDict({"Method", meth->name(), "ArgName", arg_name});
+      auto methdict;
+      methdict["Method"] = meth->name();
+      methdict["ArgName"] = arg_name;
       out->Print(methdict,
                  "def $Method$(self, $ArgName$, timeout, metadata=None, "
                  "with_call=False, protocol_options=None):\n");
       {
         IndentScope raii_method_indent(out);
-        PrintAllComments(meth, out);
+        PrintAllComments(meth);
         out->Print("raise NotImplementedError()\n");
       }
       if (!meth->server_streaming()) {
@@ -292,8 +286,9 @@ bool PrintBetaStub(const ServiceDescriptor* service, Printer* out) {
   return true;
 }
 
-bool PrintBetaServerFactory(const grpc::string& package_qualified_service_name,
-                            const ServiceDescriptor* service, Printer* out) {
+bool PrivateGenerator::PrintBetaServerFactory(
+    const grpc::string& package_qualified_service_name,
+    const ServiceDescriptor* service) {
   out->Print("\n\n");
   out->Print(
       "def beta_create_$Service$_server(servicer, pool=None, "
@@ -317,12 +312,12 @@ bool PrintBetaServerFactory(const grpc::string& package_qualified_service_name,
           grpc::string(method->server_streaming() ? "stream_" : "unary_") +
           "inline";
       grpc::string input_message_module_and_class;
-      if (!GetModuleAndMessagePath(method->input_type(), service,
+      if (!GetModuleAndMessagePath(method->input_type(),
                                    &input_message_module_and_class)) {
         return false;
       }
       grpc::string output_message_module_and_class;
-      if (!GetModuleAndMessagePath(method->output_type(), service,
+      if (!GetModuleAndMessagePath(method->output_type(),
                                    &output_message_module_and_class)) {
         return false;
       }
@@ -395,11 +390,11 @@ bool PrintBetaServerFactory(const grpc::string& package_qualified_service_name,
   return true;
 }
 
-bool PrintBetaStubFactory(const grpc::string& package_qualified_service_name,
-                          const ServiceDescriptor* service, Printer* out) {
-  map<grpc::string, grpc::string> dict = ListToDict({
-      "Service", service->name(),
-  });
+bool PrivateGenerator::PrintBetaStubFactory(
+    const grpc::string& package_qualified_service_name,
+    const ServiceDescriptor* service) {
+  map<grpc::string, grpc::string> dict;
+  dict["Service"] = service->name();
   out->Print("\n\n");
   out->Print(dict,
              "def beta_create_$Service$_stub(channel, host=None,"
@@ -421,12 +416,12 @@ bool PrintBetaStubFactory(const grpc::string& package_qualified_service_name,
           grpc::string(method->client_streaming() ? "STREAM" : "UNARY") + "_" +
           grpc::string(method->server_streaming() ? "STREAM" : "UNARY");
       grpc::string input_message_module_and_class;
-      if (!GetModuleAndMessagePath(method->input_type(), service,
+      if (!GetModuleAndMessagePath(method->input_type(),
                                    &input_message_module_and_class)) {
         return false;
       }
       grpc::string output_message_module_and_class;
-      if (!GetModuleAndMessagePath(method->output_type(), service,
+      if (!GetModuleAndMessagePath(method->output_type(),
                                    &output_message_module_and_class)) {
         return false;
       }
@@ -493,13 +488,13 @@ bool PrintBetaStubFactory(const grpc::string& package_qualified_service_name,
   return true;
 }
 
-bool PrintStub(const grpc::string& package_qualified_service_name,
-               const ServiceDescriptor* service, Printer* out) {
+bool PrivateGenerator::PrintStub(const grpc::string& package_qualified_service_name,
+                                 const ServiceDescriptor* service) {
   out->Print("\n\n");
   out->Print("class $Service$Stub(object):\n", "Service", service->name());
   {
     IndentScope raii_class_indent(out);
-    PrintAllComments(service, out);
+    PrintAllComments(service);
     out->Print("\n");
     out->Print("def __init__(self, channel):\n");
     {
@@ -518,12 +513,12 @@ bool PrintStub(const grpc::string& package_qualified_service_name,
             grpc::string(method->client_streaming() ? "stream" : "unary") +
             "_" + grpc::string(method->server_streaming() ? "stream" : "unary");
         grpc::string request_module_and_class;
-        if (!GetModuleAndMessagePath(method->input_type(), service,
+        if (!GetModuleAndMessagePath(method->input_type(),
                                      &request_module_and_class)) {
           return false;
         }
         grpc::string response_module_and_class;
-        if (!GetModuleAndMessagePath(method->output_type(), service,
+        if (!GetModuleAndMessagePath(method->output_type(),
                                      &response_module_and_class)) {
           return false;
         }
@@ -550,12 +545,12 @@ bool PrintStub(const grpc::string& package_qualified_service_name,
   return true;
 }
 
-bool PrintServicer(const ServiceDescriptor* service, Printer* out) {
+bool PrivateGenerator::PrintServicer(const ServiceDescriptor* service) {
   out->Print("\n\n");
   out->Print("class $Service$Servicer(object):\n", "Service", service->name());
   {
     IndentScope raii_class_indent(out);
-    PrintAllComments(service, out);
+    PrintAllComments(service);
     for (int i = 0; i < service->method_count(); ++i) {
       auto method = service->method(i);
       grpc::string arg_name =
@@ -565,7 +560,7 @@ bool PrintServicer(const ServiceDescriptor* service, Printer* out) {
                  method->name(), "ArgName", arg_name);
       {
         IndentScope raii_method_indent(out);
-        PrintAllComments(method, out);
+        PrintAllComments(method);
         out->Print("context.set_code(grpc.StatusCode.UNIMPLEMENTED)\n");
         out->Print("context.set_details('Method not implemented!')\n");
         out->Print("raise NotImplementedError('Method not implemented!')\n");
@@ -575,9 +570,9 @@ bool PrintServicer(const ServiceDescriptor* service, Printer* out) {
   return true;
 }
 
-bool PrintAddServicerToServer(
+bool PrivateGenerator::PrintAddServicerToServer(
     const grpc::string& package_qualified_service_name,
-    const ServiceDescriptor* service, Printer* out) {
+    const ServiceDescriptor* service) {
   out->Print("\n\n");
   out->Print("def add_$Service$Servicer_to_server(servicer, server):\n",
              "Service", service->name());
@@ -595,12 +590,12 @@ bool PrintAddServicerToServer(
             grpc::string(method->server_streaming() ? "stream" : "unary") +
             "_rpc_method_handler";
         grpc::string request_module_and_class;
-        if (!GetModuleAndMessagePath(method->input_type(), service,
+        if (!GetModuleAndMessagePath(method->input_type(),
                                      &request_module_and_class)) {
           return false;
         }
         grpc::string response_module_and_class;
-        if (!GetModuleAndMessagePath(method->output_type(), service,
+        if (!GetModuleAndMessagePath(method->output_type(),
                                      &response_module_and_class)) {
           return false;
         }
@@ -635,53 +630,170 @@ bool PrintAddServicerToServer(
   return true;
 }
 
-bool PrintPreamble(const FileDescriptor* file,
-                   const GeneratorConfiguration& config, Printer* out) {
-  out->Print("import $Package$\n", "Package", config.grpc_package_root);
+bool PrivateGenerator::PrintBetaPreamble() {
   out->Print("from $Package$ import implementations as beta_implementations\n",
              "Package", config.beta_package_root);
   out->Print("from $Package$ import interfaces as beta_interfaces\n", "Package",
              config.beta_package_root);
+  return true;
+}
+
+bool PrivateGenerator::PrintPreamble() {
+  out->Print("import $Package$\n", "Package", config.grpc_package_root);
   out->Print("from grpc.framework.common import cardinality\n");
   out->Print(
       "from grpc.framework.interfaces.face import utilities as "
       "face_utilities\n");
+  if (generate_in_pb2_grpc) {
+    out->Print("\n");
+    for (int i = 0; i < file->service_count(); ++i) {
+      const ServiceDescriptor *service = file->service(i);
+      for (int j = 0; j < service->method_count(); ++j) {
+        auto method = service->method(j);
+        const Descriptor *types[2] = {method->input_type(), method->output_type()};
+        for (int k = 0; k < 2; ++k) {
+          const Descriptor *type = types[k];
+          grpc::string type_file_name = type->file()->name();
+          grpc::string module_name = ModuleName(type_file_name);
+          grpc::string module_alias = ModuleAlias(type_file_name);
+          out->Print("import $ModuleName$ as $ModuleAlias$\n", "ModuleName", module_name, "ModuleAlias", module_alias);
+        }
+      }
+    }
+  }
   return true;
 }
 
-}  // namespace
+bool PrivateGenerator::PrintGAServices() {
+  grpc::string package = file->package();
+  if (!package.empty()) {
+    package = package.append(".");
+  }
+  for (int i = 0; i < file->service_count(); ++i) {
+    const ServiceDescriptor *service = file->service(i);
+    grpc::string package_qualified_service_name = package + service->name();
+    if (!(PrintStub(package_qualified_service_name, service) &&
+          PrintServicer(service) &&
+          PrintAddServicerToServer(package_qualified_service_name, service))) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool PrivateGenerator::PrintBetaServices() {
+  grpc::string package = file->package();
+  if (!package.empty()) {
+    package = package.append(".");
+  }
+  for (int i = 0; i < file->service_count(); ++i) {
+    const ServiceDescriptor *service = file->service(i);
+    grpc::string package_qualified_service_name = package + service->name();
+    if (!(PrintBetaServicer(service) && PrintBetaStub(service) &&
+          PrintBetaServerFactory(package_qualified_service_name, service) &&
+          PrintBetaStubFactory(package_qualified_service_name, service))) {
+      return false;
+    }
+  }
+  return true;
+}
 
-pair<bool, grpc::string> GetServices(const FileDescriptor* file,
-                                     const GeneratorConfiguration& config) {
+pair<bool, grpc::string> PrivateGenerator::GetGrpcServices() {
   grpc::string output;
   {
     // Scope the output stream so it closes and finalizes output to the string.
     StringOutputStream output_stream(&output);
-    Printer out(&output_stream, '$');
-    if (!PrintPreamble(file, config, &out)) {
-      return make_pair(false, "");
-    }
-    auto package = file->package();
-    if (!package.empty()) {
-      package = package.append(".");
-    }
-    for (int i = 0; i < file->service_count(); ++i) {
-      auto service = file->service(i);
-      auto package_qualified_service_name = package + service->name();
-      if (!(PrintStub(package_qualified_service_name, service, &out) &&
-            PrintServicer(service, &out) &&
-            PrintAddServicerToServer(package_qualified_service_name, service,
-                                     &out) &&
-            PrintBetaServicer(service, &out) && PrintBetaStub(service, &out) &&
-            PrintBetaServerFactory(package_qualified_service_name, service,
-                                   &out) &&
-            PrintBetaStubFactory(package_qualified_service_name, service,
-                                 &out))) {
+    Printer out_printer(&output_stream, '$');
+    out = &out_printer;
+
+    if (generate_in_pb2_grpc) {
+      if (!PrintPreamble()) {
         return make_pair(false, "");
       }
+      if (!PrintGAServices()) {
+        return make_pair(false, "");
+      }
+    } else {
+      out->Print("try:\n");
+      {
+        IndentScope raii_dict_try_indent(out);
+        out->Print("# THESE ELEMENTS WILL BE DEPRECATED.\n"
+                   "# Please use the generated *_pb2_grpc.py files instead.\n");
+        if (!PrintPreamble()) {
+          return make_pair(false, "");
+        }
+        if (!PrintBetaPreamble()) {
+          return make_pair(false, "");
+        }
+        if (!PrintGAServices()) {
+          return make_pair(false, "");
+        }
+        if (!PrintBetaServices()) {
+          return make_pair(false, "");
+        }
+      }
+      out->Print("except ImportError:\n");
+      {
+        IndentScope raii_dict_except_indent(out);
+        out->Print("pass");
+      }
     }
   }
   return make_pair(true, std::move(output));
 }
 
+}  // namespace
+
+GeneratorConfiguration::GeneratorConfiguration()
+    : grpc_package_root("grpc"), beta_package_root("grpc.beta") {}
+
+PythonGrpcGenerator::PythonGrpcGenerator(const GeneratorConfiguration& config)
+    : config_(config) {}
+
+PythonGrpcGenerator::~PythonGrpcGenerator() {}
+
+bool PythonGrpcGenerator::Generate(const FileDescriptor* file,
+                                   const grpc::string& parameter,
+                                   GeneratorContext* context,
+                                   grpc::string* error) const {
+  // Get output file name.
+  grpc::string pb2_file_name;
+  grpc::string pb2_grpc_file_name;
+  static const int proto_suffix_length = strlen(".proto");
+  if (file->name().size() > static_cast<size_t>(proto_suffix_length) &&
+      file->name().find_last_of(".proto") == file->name().size() - 1) {
+    grpc::string base = file->name().substr(
+        0, file->name().size() - proto_suffix_length);
+    pb2_file_name = base + "_pb2.py";
+    pb2_grpc_file_name = base + "_pb2_grpc.py";
+  } else {
+    *error = "Invalid proto file name. Proto file must end with .proto";
+    return false;
+  }
+
+  PrivateGenerator generator(config_, file);
+
+  std::unique_ptr<ZeroCopyOutputStream> pb2_output(
+      context->OpenForAppend(pb2_file_name));
+  std::unique_ptr<ZeroCopyOutputStream> grpc_output(
+      context->Open(pb2_grpc_file_name));
+  CodedOutputStream pb2_coded_out(pb2_output.get());
+  CodedOutputStream grpc_coded_out(grpc_output.get());
+  bool success = false;
+  grpc::string pb2_code;
+  grpc::string grpc_code;
+  generator.generate_in_pb2_grpc = false;
+  tie(success, pb2_code) = generator.GetGrpcServices();
+  if (success) {
+    generator.generate_in_pb2_grpc = true;
+    tie(success, grpc_code) = generator.GetGrpcServices();
+    if (success) {
+      pb2_coded_out.WriteRaw(pb2_code.data(), pb2_code.size());
+      grpc_coded_out.WriteRaw(grpc_code.data(), grpc_code.size());
+      return true;
+    }
+  }
+  return false;
+}
+
 }  // namespace grpc_python_generator
diff --git a/src/compiler/python_generator.h b/src/compiler/python_generator.h
index 9bbb83bca6..6a95255d40 100644
--- a/src/compiler/python_generator.h
+++ b/src/compiler/python_generator.h
@@ -62,10 +62,6 @@ class PythonGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
   GeneratorConfiguration config_;
 };
 
-std::pair<bool, grpc::string> GetServices(
-    const grpc::protobuf::FileDescriptor* file,
-    const GeneratorConfiguration& config);
-
 }  // namespace grpc_python_generator
 
 #endif  // GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H
diff --git a/src/python/grpcio_health_checking/.gitignore b/src/python/grpcio_health_checking/.gitignore
index 85af466886..432c3194f0 100644
--- a/src/python/grpcio_health_checking/.gitignore
+++ b/src/python/grpcio_health_checking/.gitignore
@@ -1,5 +1,6 @@
 *.proto
 *_pb2.py
+*_pb2_grpc.py
 build/
 grpcio_health_checking.egg-info/
 dist/
diff --git a/src/python/grpcio_tests/.gitignore b/src/python/grpcio_tests/.gitignore
index fc620135dc..dcba283a8c 100644
--- a/src/python/grpcio_tests/.gitignore
+++ b/src/python/grpcio_tests/.gitignore
@@ -1,4 +1,5 @@
 proto/
 src/
 *_pb2.py
+*_pb2_grpc.py
 *.egg-info/
diff --git a/src/python/grpcio_tests/setup.py b/src/python/grpcio_tests/setup.py
index 7384206602..01d5fa875b 100644
--- a/src/python/grpcio_tests/setup.py
+++ b/src/python/grpcio_tests/setup.py
@@ -80,8 +80,14 @@ PACKAGE_DATA = {
         'credentials/server1.key',
         'credentials/server1.pem',
     ],
-    'tests.protoc_plugin': [
-        'protoc_plugin_test.proto',
+    'tests.protoc_plugin.protos.invocation_testing': [
+        'same.proto',
+    ],
+    'tests.protoc_plugin.protos.invocation_testing.split_messages': [
+        'messages.proto',
+    ],
+    'tests.protoc_plugin.protos.invocation_testing.split_services': [
+        'services.proto',
     ],
     'tests.unit': [
         'credentials/ca.pem',
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/_split_definitions_test.py b/src/python/grpcio_tests/tests/protoc_plugin/_split_definitions_test.py
new file mode 100644
index 0000000000..089366a8c7
--- /dev/null
+++ b/src/python/grpcio_tests/tests/protoc_plugin/_split_definitions_test.py
@@ -0,0 +1,304 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import collections
+from concurrent import futures
+import contextlib
+import distutils.spawn
+import errno
+import importlib
+import os
+import os.path
+import pkgutil
+import shutil
+import subprocess
+import sys
+import tempfile
+import threading
+import unittest
+
+import grpc
+from grpc.tools import protoc
+from tests.unit.framework.common import test_constants
+
+_MESSAGES_IMPORT = b'import "messages.proto";'
+
+@contextlib.contextmanager
+def _system_path(path):
+  old_system_path = sys.path[:]
+  sys.path = sys.path[0:1] + path + sys.path[1:]
+  yield
+  sys.path = old_system_path
+
+
+class DummySplitServicer(object):
+
+  def __init__(self, request_class, response_class):
+    self.request_class = request_class
+    self.response_class = response_class
+
+  def Call(self, request, context):
+    return self.response_class()
+
+
+class SeparateTestMixin(object):
+
+  def testImportAttributes(self):
+    with _system_path([self.python_out_directory]):
+      pb2 = importlib.import_module(self.pb2_import)
+    pb2.Request
+    pb2.Response
+    if self.should_find_services_in_pb2:
+      pb2.TestServiceServicer
+    else:
+      with self.assertRaises(AttributeError):
+        pb2.TestServiceServicer
+
+    with _system_path([self.grpc_python_out_directory]):
+      pb2_grpc = importlib.import_module(self.pb2_grpc_import)
+    pb2_grpc.TestServiceServicer
+    with self.assertRaises(AttributeError):
+      pb2_grpc.Request
+    with self.assertRaises(AttributeError):
+      pb2_grpc.Response
+
+  def testCall(self):
+    with _system_path([self.python_out_directory]):
+      pb2 = importlib.import_module(self.pb2_import)
+    with _system_path([self.grpc_python_out_directory]):
+      pb2_grpc = importlib.import_module(self.pb2_grpc_import)
+    server = grpc.server(
+        futures.ThreadPoolExecutor(max_workers=test_constants.POOL_SIZE))
+    pb2_grpc.add_TestServiceServicer_to_server(
+        DummySplitServicer(
+            pb2.Request, pb2.Response), server)
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    channel = grpc.insecure_channel('localhost:{}'.format(port))
+    stub = pb2_grpc.TestServiceStub(channel)
+    request = pb2.Request()
+    expected_response = pb2.Response()
+    response = stub.Call(request)
+    self.assertEqual(expected_response, response)
+
+
+class CommonTestMixin(object):
+
+  def testImportAttributes(self):
+    with _system_path([self.python_out_directory]):
+      pb2 = importlib.import_module(self.pb2_import)
+    pb2.Request
+    pb2.Response
+    if self.should_find_services_in_pb2:
+      pb2.TestServiceServicer
+    else:
+      with self.assertRaises(AttributeError):
+        pb2.TestServiceServicer
+
+    with _system_path([self.grpc_python_out_directory]):
+      pb2_grpc = importlib.import_module(self.pb2_grpc_import)
+    pb2_grpc.TestServiceServicer
+    with self.assertRaises(AttributeError):
+      pb2_grpc.Request
+    with self.assertRaises(AttributeError):
+      pb2_grpc.Response
+
+  def testCall(self):
+    with _system_path([self.python_out_directory]):
+      pb2 = importlib.import_module(self.pb2_import)
+    with _system_path([self.grpc_python_out_directory]):
+      pb2_grpc = importlib.import_module(self.pb2_grpc_import)
+    server = grpc.server(
+        futures.ThreadPoolExecutor(max_workers=test_constants.POOL_SIZE))
+    pb2_grpc.add_TestServiceServicer_to_server(
+        DummySplitServicer(
+            pb2.Request, pb2.Response), server)
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    channel = grpc.insecure_channel('localhost:{}'.format(port))
+    stub = pb2_grpc.TestServiceStub(channel)
+    request = pb2.Request()
+    expected_response = pb2.Response()
+    response = stub.Call(request)
+    self.assertEqual(expected_response, response)
+
+
+class SameSeparateTest(unittest.TestCase, SeparateTestMixin):
+
+  def setUp(self):
+    same_proto_contents = pkgutil.get_data(
+        'tests.protoc_plugin.protos.invocation_testing', 'same.proto')
+    self.directory = tempfile.mkdtemp(suffix='same_separate', dir='.')
+    self.proto_directory = os.path.join(self.directory, 'proto_path')
+    self.python_out_directory = os.path.join(self.directory, 'python_out')
+    self.grpc_python_out_directory = os.path.join(self.directory, 'grpc_python_out')
+    os.makedirs(self.proto_directory)
+    os.makedirs(self.python_out_directory)
+    os.makedirs(self.grpc_python_out_directory)
+    same_proto_file = os.path.join(self.proto_directory, 'same_separate.proto')
+    open(same_proto_file, 'wb').write(same_proto_contents)
+    protoc_result = protoc.main([
+        '',
+        '--proto_path={}'.format(self.proto_directory),
+        '--python_out={}'.format(self.python_out_directory),
+        '--grpc_python_out={}'.format(self.grpc_python_out_directory),
+        same_proto_file,
+    ])
+    if protoc_result != 0:
+      raise Exception("unexpected protoc error")
+    open(os.path.join(self.grpc_python_out_directory, '__init__.py'), 'w').write('')
+    open(os.path.join(self.python_out_directory, '__init__.py'), 'w').write('')
+    self.pb2_import = 'same_separate_pb2'
+    self.pb2_grpc_import = 'same_separate_pb2_grpc'
+    self.should_find_services_in_pb2 = False
+
+  def tearDown(self):
+    shutil.rmtree(self.directory)
+
+
+class SameCommonTest(unittest.TestCase, CommonTestMixin):
+
+  def setUp(self):
+    same_proto_contents = pkgutil.get_data(
+        'tests.protoc_plugin.protos.invocation_testing', 'same.proto')
+    self.directory = tempfile.mkdtemp(suffix='same_common', dir='.')
+    self.proto_directory = os.path.join(self.directory, 'proto_path')
+    self.python_out_directory = os.path.join(self.directory, 'python_out')
+    self.grpc_python_out_directory = self.python_out_directory
+    os.makedirs(self.proto_directory)
+    os.makedirs(self.python_out_directory)
+    same_proto_file = os.path.join(self.proto_directory, 'same_common.proto')
+    open(same_proto_file, 'wb').write(same_proto_contents)
+    protoc_result = protoc.main([
+        '',
+        '--proto_path={}'.format(self.proto_directory),
+        '--python_out={}'.format(self.python_out_directory),
+        '--grpc_python_out={}'.format(self.grpc_python_out_directory),
+        same_proto_file,
+    ])
+    if protoc_result != 0:
+      raise Exception("unexpected protoc error")
+    open(os.path.join(self.python_out_directory, '__init__.py'), 'w').write('')
+    self.pb2_import = 'same_common_pb2'
+    self.pb2_grpc_import = 'same_common_pb2_grpc'
+    self.should_find_services_in_pb2 = True
+
+  def tearDown(self):
+    shutil.rmtree(self.directory)
+
+
+class SplitCommonTest(unittest.TestCase, CommonTestMixin):
+
+  def setUp(self):
+    services_proto_contents = pkgutil.get_data(
+        'tests.protoc_plugin.protos.invocation_testing.split_services',
+        'services.proto')
+    messages_proto_contents = pkgutil.get_data(
+        'tests.protoc_plugin.protos.invocation_testing.split_messages',
+        'messages.proto')
+    self.directory = tempfile.mkdtemp(suffix='split_common', dir='.')
+    self.proto_directory = os.path.join(self.directory, 'proto_path')
+    self.python_out_directory = os.path.join(self.directory, 'python_out')
+    self.grpc_python_out_directory = self.python_out_directory
+    os.makedirs(self.proto_directory)
+    os.makedirs(self.python_out_directory)
+    services_proto_file = os.path.join(self.proto_directory,
+                                       'split_common_services.proto')
+    messages_proto_file = os.path.join(self.proto_directory,
+                                       'split_common_messages.proto')
+    open(services_proto_file, 'wb').write(services_proto_contents.replace(
+        _MESSAGES_IMPORT,
+        b'import "split_common_messages.proto";'
+    ))
+    open(messages_proto_file, 'wb').write(messages_proto_contents)
+    protoc_result = protoc.main([
+        '',
+        '--proto_path={}'.format(self.proto_directory),
+        '--python_out={}'.format(self.python_out_directory),
+        '--grpc_python_out={}'.format(self.python_out_directory),
+        services_proto_file,
+        messages_proto_file,
+    ])
+    if protoc_result != 0:
+      raise Exception("unexpected protoc error")
+    open(os.path.join(self.python_out_directory, '__init__.py'), 'w').write('')
+    self.pb2_import = 'split_common_messages_pb2'
+    self.pb2_grpc_import = 'split_common_services_pb2_grpc'
+    self.should_find_services_in_pb2 = False
+
+  def tearDown(self):
+    shutil.rmtree(self.directory)
+
+
+class SplitSeparateTest(unittest.TestCase, SeparateTestMixin):
+
+  def setUp(self):
+    services_proto_contents = pkgutil.get_data(
+        'tests.protoc_plugin.protos.invocation_testing.split_services',
+        'services.proto')
+    messages_proto_contents = pkgutil.get_data(
+        'tests.protoc_plugin.protos.invocation_testing.split_messages',
+        'messages.proto')
+    self.directory = tempfile.mkdtemp(suffix='split_separate', dir='.')
+    self.proto_directory = os.path.join(self.directory, 'proto_path')
+    self.python_out_directory = os.path.join(self.directory, 'python_out')
+    self.grpc_python_out_directory = os.path.join(self.directory, 'grpc_python_out')
+    os.makedirs(self.proto_directory)
+    os.makedirs(self.python_out_directory)
+    os.makedirs(self.grpc_python_out_directory)
+    services_proto_file = os.path.join(self.proto_directory,
+                                       'split_separate_services.proto')
+    messages_proto_file = os.path.join(self.proto_directory,
+                                       'split_separate_messages.proto')
+    open(services_proto_file, 'wb').write(services_proto_contents.replace(
+        _MESSAGES_IMPORT,
+        b'import "split_separate_messages.proto";'
+    ))
+    open(messages_proto_file, 'wb').write(messages_proto_contents)
+    protoc_result = protoc.main([
+        '',
+        '--proto_path={}'.format(self.proto_directory),
+        '--python_out={}'.format(self.python_out_directory),
+        '--grpc_python_out={}'.format(self.grpc_python_out_directory),
+        services_proto_file,
+        messages_proto_file,
+    ])
+    if protoc_result != 0:
+      raise Exception("unexpected protoc error")
+    open(os.path.join(self.python_out_directory, '__init__.py'), 'w').write('')
+    self.pb2_import = 'split_separate_messages_pb2'
+    self.pb2_grpc_import = 'split_separate_services_pb2_grpc'
+    self.should_find_services_in_pb2 = False
+
+  def tearDown(self):
+    shutil.rmtree(self.directory)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/__init__.py b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/__init__.py
new file mode 100644
index 0000000000..2f88fa0412
--- /dev/null
+++ b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/same.proto b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/same.proto
new file mode 100644
index 0000000000..269e2fd2c7
--- /dev/null
+++ b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/same.proto
@@ -0,0 +1,39 @@
+// Copyright 2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package grpc_protoc_plugin.invocation_testing;
+
+message Request {}
+message Response {}
+
+service TestService {
+  rpc Call(Request) returns (Response);
+}
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_messages/__init__.py b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_messages/__init__.py
new file mode 100644
index 0000000000..2f88fa0412
--- /dev/null
+++ b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_messages/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_messages/messages.proto b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_messages/messages.proto
new file mode 100644
index 0000000000..de22dae049
--- /dev/null
+++ b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_messages/messages.proto
@@ -0,0 +1,35 @@
+// Copyright 2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package grpc_protoc_plugin.invocation_testing.split;
+
+message Request {}
+message Response {}
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_services/__init__.py b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_services/__init__.py
new file mode 100644
index 0000000000..2f88fa0412
--- /dev/null
+++ b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_services/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_services/services.proto b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_services/services.proto
new file mode 100644
index 0000000000..af999cd48d
--- /dev/null
+++ b/src/python/grpcio_tests/tests/protoc_plugin/protos/invocation_testing/split_services/services.proto
@@ -0,0 +1,38 @@
+// Copyright 2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+import "messages.proto";
+
+package grpc_protoc_plugin.invocation_testing.split;
+
+service TestService {
+  rpc Call(Request) returns (Response);
+}
diff --git a/src/python/grpcio_tests/tests/tests.json b/src/python/grpcio_tests/tests/tests.json
index 2e85f1f397..dd4a0257f5 100644
--- a/src/python/grpcio_tests/tests/tests.json
+++ b/src/python/grpcio_tests/tests/tests.json
@@ -1,45 +1,49 @@
 [
-  "_api_test.AllTest",
-  "_api_test.ChannelConnectivityTest",
-  "_api_test.ChannelTest",
-  "_auth_test.AccessTokenCallCredentialsTest",
-  "_auth_test.GoogleCallCredentialsTest",
-  "_beta_features_test.BetaFeaturesTest",
-  "_beta_features_test.ContextManagementAndLifecycleTest",
-  "_cancel_many_calls_test.CancelManyCallsTest",
-  "_channel_args_test.ChannelArgsTest",
-  "_channel_connectivity_test.ChannelConnectivityTest",
-  "_channel_ready_future_test.ChannelReadyFutureTest",
-  "_channel_test.ChannelTest",
-  "_compression_test.CompressionTest",
-  "_connectivity_channel_test.ConnectivityStatesTest",
-  "_credentials_test.CredentialsTest",
-  "_empty_message_test.EmptyMessageTest",
-  "_exit_test.ExitTest",
-  "_face_interface_test.DynamicInvokerBlockingInvocationInlineServiceTest",
-  "_face_interface_test.DynamicInvokerFutureInvocationAsynchronousEventServiceTest",
-  "_face_interface_test.GenericInvokerBlockingInvocationInlineServiceTest",
-  "_face_interface_test.GenericInvokerFutureInvocationAsynchronousEventServiceTest",
-  "_face_interface_test.MultiCallableInvokerBlockingInvocationInlineServiceTest",
-  "_face_interface_test.MultiCallableInvokerFutureInvocationAsynchronousEventServiceTest",
-  "_health_servicer_test.HealthServicerTest",
-  "_implementations_test.CallCredentialsTest",
-  "_implementations_test.ChannelCredentialsTest",
-  "_insecure_interop_test.InsecureInteropTest",
-  "_logging_pool_test.LoggingPoolTest",
-  "_metadata_code_details_test.MetadataCodeDetailsTest",
-  "_metadata_test.MetadataTest",
-  "_not_found_test.NotFoundTest",
-  "_python_plugin_test.PythonPluginTest",
-  "_read_some_but_not_all_responses_test.ReadSomeButNotAllResponsesTest",
-  "_reflection_servicer_test.ReflectionServicerTest",
-  "_rpc_test.RPCTest",
-  "_sanity_test.Sanity",
-  "_secure_interop_test.SecureInteropTest",
-  "_thread_cleanup_test.CleanupThreadTest",
-  "_utilities_test.ChannelConnectivityTest",
-  "beta_python_plugin_test.PythonPluginTest",
-  "cygrpc_test.InsecureServerInsecureClient",
-  "cygrpc_test.SecureServerSecureClient",
-  "cygrpc_test.TypeSmokeTest"
+  "health_check._health_servicer_test.HealthServicerTest",
+  "interop._insecure_interop_test.InsecureInteropTest",
+  "interop._secure_interop_test.SecureInteropTest",
+  "protoc_plugin._python_plugin_test.PythonPluginTest",
+  "protoc_plugin._split_definitions_test.SameCommonTest",
+  "protoc_plugin._split_definitions_test.SameSeparateTest",
+  "protoc_plugin._split_definitions_test.SplitCommonTest",
+  "protoc_plugin._split_definitions_test.SplitSeparateTest",
+  "protoc_plugin.beta_python_plugin_test.PythonPluginTest",
+  "reflection._reflection_servicer_test.ReflectionServicerTest",
+  "unit._api_test.AllTest",
+  "unit._api_test.ChannelConnectivityTest",
+  "unit._api_test.ChannelTest",
+  "unit._auth_test.AccessTokenCallCredentialsTest",
+  "unit._auth_test.GoogleCallCredentialsTest",
+  "unit._channel_args_test.ChannelArgsTest",
+  "unit._channel_connectivity_test.ChannelConnectivityTest",
+  "unit._channel_ready_future_test.ChannelReadyFutureTest",
+  "unit._compression_test.CompressionTest",
+  "unit._credentials_test.CredentialsTest",
+  "unit._cython._cancel_many_calls_test.CancelManyCallsTest",
+  "unit._cython._channel_test.ChannelTest",
+  "unit._cython._read_some_but_not_all_responses_test.ReadSomeButNotAllResponsesTest",
+  "unit._cython.cygrpc_test.InsecureServerInsecureClient",
+  "unit._cython.cygrpc_test.SecureServerSecureClient",
+  "unit._cython.cygrpc_test.TypeSmokeTest",
+  "unit._empty_message_test.EmptyMessageTest",
+  "unit._exit_test.ExitTest",
+  "unit._metadata_code_details_test.MetadataCodeDetailsTest",
+  "unit._metadata_test.MetadataTest",
+  "unit._rpc_test.RPCTest",
+  "unit._sanity._sanity_test.Sanity",
+  "unit._thread_cleanup_test.CleanupThreadTest",
+  "unit.beta._beta_features_test.BetaFeaturesTest",
+  "unit.beta._beta_features_test.ContextManagementAndLifecycleTest",
+  "unit.beta._connectivity_channel_test.ConnectivityStatesTest",
+  "unit.beta._face_interface_test.DynamicInvokerBlockingInvocationInlineServiceTest",
+  "unit.beta._face_interface_test.DynamicInvokerFutureInvocationAsynchronousEventServiceTest",
+  "unit.beta._face_interface_test.GenericInvokerBlockingInvocationInlineServiceTest",
+  "unit.beta._face_interface_test.GenericInvokerFutureInvocationAsynchronousEventServiceTest",
+  "unit.beta._face_interface_test.MultiCallableInvokerBlockingInvocationInlineServiceTest",
+  "unit.beta._face_interface_test.MultiCallableInvokerFutureInvocationAsynchronousEventServiceTest",
+  "unit.beta._implementations_test.CallCredentialsTest",
+  "unit.beta._implementations_test.ChannelCredentialsTest",
+  "unit.beta._not_found_test.NotFoundTest",
+  "unit.beta._utilities_test.ChannelConnectivityTest",
+  "unit.framework.foundation._logging_pool_test.LoggingPoolTest"
 ]