pandaproxy/sr: protobuf rendering: add test for message oneofs normal…

…ization ordering

(cherry picked from commit 3e4e26a)

src/v/pandaproxy/schema_registry/test/protobuf_rendering.cc

@@ -165,4 +165,5 @@ INSTANTIATE_TEST_SUITE_P(
     "repeated_custom_options",
     "enum_ordering",
     "message_ordering",
-    "service_ordering"));
+    "service_ordering",
+    "oneof_ordering"));

src/v/pandaproxy/schema_registry/test/testdata/protobuf/oneof_ordering_input.proto

@@ -0,0 +1,24 @@
+syntax = "proto3";
+
+// Oneof fields should be ordered by their index, regardless
+// of what field values they have internally. Fields internally
+// are safe to reorder
+
+message OneofsMessage {
+  oneof first_oneof {
+    float third_f = 7;
+    double third_d = 3;
+  }
+  double d = 6;
+  uint32 ui32 = 5;
+  int64 i64 = 4;
+  oneof second_oneof {
+    float second_f = 8;
+    double second_d = 2;
+  }
+  oneof third_oneof {
+    float first_f = 9;
+    double first_d = 1;
+  }
+}
+

src/v/pandaproxy/schema_registry/test/testdata/protobuf/oneof_ordering_normalized.proto

@@ -0,0 +1,20 @@
+syntax = "proto3";
+
+message OneofsMessage {
+  int64 i64 = 4;
+  uint32 ui32 = 5;
+  double d = 6;
+  oneof first_oneof {
+    double third_d = 3;
+    float third_f = 7;
+  }
+  oneof second_oneof {
+    double second_d = 2;
+    float second_f = 8;
+  }
+  oneof third_oneof {
+    double first_d = 1;
+    float first_f = 9;
+  }
+}
+

src/v/pandaproxy/schema_registry/test/testdata/protobuf/oneof_ordering_sanitized.proto

@@ -0,0 +1,20 @@
+syntax = "proto3";
+
+message OneofsMessage {
+  oneof first_oneof {
+    float third_f = 7;
+    double third_d = 3;
+  }
+  double d = 6;
+  uint32 ui32 = 5;
+  int64 i64 = 4;
+  oneof second_oneof {
+    float second_f = 8;
+    double second_d = 2;
+  }
+  oneof third_oneof {
+    float first_f = 9;
+    double first_d = 1;
+  }
+}
+