Two tests for Ruby code generator:

- A golden-file test that ensures protoc produces known-valid output.
- A Ruby test that loads that golden file and ensures it actually works
  with the extension.

This split strategy allows us to test end-to-end without needing to
integrate the Ruby gem build system and the protoc build system. This is
desirable because we do not want a gem build/install to depend on
building protoc, and we do not want building protoc to depend on
building and testing the gem.

2 files changed, 117 insertions, 0 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 3a469fd7..6fd8bd2b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -458,6 +458,7 @@ protobuf_test_SOURCES =                                        \
   google/protobuf/compiler/java/java_plugin_unittest.cc        \
   google/protobuf/compiler/java/java_doc_comment_unittest.cc   \
   google/protobuf/compiler/python/python_plugin_unittest.cc    \
+  google/protobuf/compiler/ruby/ruby_generator_unittest.cc     \
   $(COMMON_TEST_SOURCES)
 nodist_protobuf_test_SOURCES = $(protoc_outputs)
 
diff --git a/src/google/protobuf/compiler/ruby/ruby_generator_unittest.cc b/src/google/protobuf/compiler/ruby/ruby_generator_unittest.cc
new file mode 100644
index 00000000..971fb739
--- /dev/null
+++ b/src/google/protobuf/compiler/ruby/ruby_generator_unittest.cc
@@ -0,0 +1,116 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2014 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#include <memory>
+
+#include <google/protobuf/compiler/ruby/ruby_generator.h>
+#include <google/protobuf/compiler/command_line_interface.h>
+#include <google/protobuf/io/zero_copy_stream.h>
+#include <google/protobuf/io/printer.h>
+
+#include <google/protobuf/testing/googletest.h>
+#include <gtest/gtest.h>
+#include <google/protobuf/testing/file.h>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace python {
+namespace {
+
+class TestGenerator : public CodeGenerator {
+ public:
+  TestGenerator() {}
+  ~TestGenerator() {}
+
+  virtual bool Generate(const FileDescriptor* file,
+                        const string& parameter,
+                        GeneratorContext* context,
+                        string* error) const {
+    TryInsert("test_pb2.py", "imports", context);
+    TryInsert("test_pb2.py", "module_scope", context);
+    TryInsert("test_pb2.py", "class_scope:foo.Bar", context);
+    TryInsert("test_pb2.py", "class_scope:foo.Bar.Baz", context);
+    return true;
+  }
+
+  void TryInsert(const string& filename, const string& insertion_point,
+                 GeneratorContext* context) const {
+    google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(
+        context->OpenForInsert(filename, insertion_point));
+    io::Printer printer(output.get(), '$');
+    printer.Print("// inserted $name$\n", "name", insertion_point);
+  }
+};
+
+// This test is a simple golden-file test over the output of the Ruby code
+// generator. When we make changes to the Ruby extension and alter the Ruby code
+// generator to use those changes, we should (i) manually test the output of the
+// code generator with the extension, and (ii) update the golden output above.
+// Some day, we may integrate build systems between protoc and the language
+// extensions to the point where we can do this test in a more automated way.
+
+TEST(RubyGeneratorTest, GeneratorTest) {
+  google::protobuf::compiler::CommandLineInterface cli;
+  cli.SetInputsAreProtoPathRelative(true);
+
+  ruby::Generator ruby_generator;
+  cli.RegisterGenerator("--ruby_out", &ruby_generator, "");
+
+  string path_arg = "-I" + TestSourceDir() + "/ruby/tests";
+  string ruby_out = "--ruby_out=" + TestTempDir();
+  const char* argv[] = {
+    "protoc",
+    path_arg.c_str(),
+    ruby_out.c_str(),
+    "generated_code.proto",
+  };
+
+  EXPECT_EQ(0, cli.Run(4, argv));
+
+  string output;
+  GOOGLE_CHECK_OK(File::GetContents(TestTempDir() + "/generated_code.rb",
+                                    &output,
+                                    true));
+
+  string expected_output;
+  GOOGLE_CHECK_OK(File::GetContents(
+      TestSourceDir() + "/ruby/tests/generated_code.rb",
+      &expected_output,
+      true));
+
+  EXPECT_EQ(expected_output, output);
+}
+
+}  // namespace
+}  // namespace python
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google