Ruby: Allow doc gapic generation to generate tests.

src/main/java/com/google/api/codegen/gapic/MainGapicProviderFactory.java

@@ -431,7 +431,7 @@ public static List<GapicProvider<? extends Object>> defaultCreate(
           providers.add(messageProvider);
         }
       }
-      if (generatorConfig.enableTestGenerator() && id.equals(RUBY)) {
+      if (generatorConfig.enableTestGenerator()) {
         GapicCodePathMapper rubyTestPathMapper =
             CommonGapicCodePathMapper.newBuilder()
                 .setPrefix("test")

src/test/java/com/google/api/codegen/testdata/ruby_doc_smoke_test_library.baseline

@@ -0,0 +1,41 @@
+============== file: test/library/v1/library_service_smoke_test.rb ==============
+# Copyright 2017, Google Inc. All rights reserved.
+#
+# Licensed 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.
+
+# AUTO GENERATED BY GAPIC
+
+require "minitest/autorun"
+require "minitest/spec"
+require "library/v1/library_service_client"
+
+describe "LibraryServiceSmokeTest" do
+  it "runs one smoke test with update_book" do
+    unless ENV["SMOKE_TEST_PROJECT"]
+      fail "Usage: SMOKE_TEST_PROJECT=<project_id> ruby #{$0}"
+    end
+    project_id = ENV["SMOKE_TEST_PROJECT"].freeze
+
+    Book = Google::Example::Library::V1::Book
+    FieldMask = Google::Protobuf::FieldMask
+    LibraryServiceClient = Library::V1::LibraryServiceClient
+    Rating = Google::Example::Library::V1::Book::Rating
+    UpdateBookRequest = Google::Example::Library::V1::UpdateBookRequest
+
+    library_service_client = LibraryServiceClient.new
+    formatted_name = LibraryServiceClient.book_path("testShelf-" + Time.new.to_i.to_s, project_id)
+    rating = Rating::GOOD
+    book = Book.new(rating: rating)
+    response = library_service_client.update_book(formatted_name, book)
+  end
+end