Add tests for JavaNano maps.

javanano/pom.xml

@@ -94,6 +94,7 @@
                   <arg value="src/test/java/com/google/protobuf/nano/unittest_multiple_nameclash_nano.proto" />
                   <arg value="src/test/java/com/google/protobuf/nano/unittest_enum_class_nano.proto" />
                   <arg value="src/test/java/com/google/protobuf/nano/unittest_repeated_merge_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/map_test.proto" />
                 </exec>
                 <exec executable="../src/protoc">
                   <arg value="--javanano_out=store_unknown_fields=true,generate_equals=true:target/generated-test-sources" />

javanano/src/test/java/com/google/protobuf/nano/map_test.proto

@@ -0,0 +1,52 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 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.
+
+syntax = "proto3";
+
+package map_test;
+
+mesasge TestMap {
+  message MessageValue {
+    int32 value = 1;
+  }
+  enum EnumValue {
+    FOO = 0;
+    BAR = 1;
+    BAZ = 2;
+    QUX = 3;
+  }
+
+  map<int32, int32>        int32_to_int32_field = 1;
+  map<int32, string>       int32_to_string_field = 2;
+  map<int32, bytes>        int32_to_bytes_field = 3;
+  map<int32, EnumValue>    int32_to_enum_field = 4;
+  map<int32, MessageValue> int32_to_message_field = 5;
+  map<string, int32>       string_to_int32_field = 6;
+}