Add testcase for issue nanopb#229

tests/regression/issue_229/SConscript

@@ -0,0 +1,13 @@
+# Regression test for Issue 229: problem encoding message that has
+# multiple oneof fields
+Import('env')
+
+env.NanopbProto('multiple_oneof')
+
+p = env.Program(["multiple_oneof.c",
+                 "multiple_oneof.pb.c",
+                 "$COMMON/pb_decode.o",
+                 "$COMMON/pb_encode.o",
+                 "$COMMON/pb_common.o"])
+env.RunTest(p)
+

tests/regression/issue_229/multiple_oneof.c

@@ -0,0 +1,35 @@
+#include "multiple_oneof.pb.h"
+#include <unittests.h>
+#include <pb_encode.h>
+#include <pb_decode.h>
+
+int main()
+{
+    int status = 0;
+    uint8_t buf[128];
+    size_t msglen;
+
+    {
+        pb_ostream_t stream = pb_ostream_from_buffer(buf, sizeof(buf));
+        MainMessage msg = MainMessage_init_zero;
+        msg.which_oneof1 = MainMessage_oneof1_uint32_tag;
+        msg.oneof1.oneof1_uint32 = 1234;
+        msg.which_oneof2 = MainMessage_oneof2_uint32_tag;
+        msg.oneof2.oneof2_uint32 = 5678;
+        TEST(pb_encode(&stream, MainMessage_fields, &msg));
+        msglen = stream.bytes_written;
+    }
+
+    {
+        pb_istream_t stream = pb_istream_from_buffer(buf, msglen);
+        MainMessage msg = MainMessage_init_zero;
+        TEST(pb_decode(&stream, MainMessage_fields, &msg));
+        TEST(msg.which_oneof1 == MainMessage_oneof1_uint32_tag);
+        TEST(msg.oneof1.oneof1_uint32 == 1234);
+        TEST(msg.which_oneof2 == MainMessage_oneof2_uint32_tag);
+        TEST(msg.oneof2.oneof2_uint32 == 5678);
+    }
+
+    return status;
+}
+

tests/regression/issue_229/multiple_oneof.proto

@@ -0,0 +1,11 @@
+syntax = "proto2";
+
+message MainMessage {
+    oneof oneof1 {
+        uint32 oneof1_uint32 = 1;
+    }
+    oneof oneof2 {
+        uint32 oneof2_uint32 = 2;
+    }
+}
+