Add a simple test to make sure RPC Services are ignored (#2)

testdata/test7.proto

@@ -0,0 +1,13 @@
+syntax = "proto3";
+package example;
+
+message Example {
+  string foo = 1;
+  string bar = 2;
+  string baz = 3;
+}
+
+// Make sure that services are ignored.
+service ExampleService {
+  rpc DoExample(Example) returns (Example);
+}

testdata/test7.rules

@@ -0,0 +1,15 @@
+// @@START_GENERATED_FUNCTIONS@@
+function is_ExampleMessage(resource) {
+  return ((resource.keys().hasAll([]) && resource.size() == 0)) ||
+          (resource.keys().hasAll(['foo']) && resource.size() == 1)) ||
+          (resource.keys().hasAll(['bar']) && resource.size() == 1)) ||
+          (resource.keys().hasAll(['baz']) && resource.size() == 1)) ||
+          (resource.keys().hasAll(['bar','foo']) && resource.size() == 2)) ||
+          (resource.keys().hasAll(['baz','foo']) && resource.size() == 2)) ||
+          (resource.keys().hasAll(['baz','bar']) && resource.size() == 2)) ||
+          (resource.keys().hasAll(['baz','bar','foo']) && resource.size() == 3))) &&
+          ((resource.foo == null) || (resource.foo is string)) &&
+          ((resource.bar == null) || (resource.bar is string)) &&
+          ((resource.baz == null) || (resource.baz is string));
+}
+// @@END_GENERATED_FUNCTIONS@@