1 files changed, 73 insertions, 0 deletions
diff --git a/pw_protobuf/varint_size_test.cc b/pw_protobuf/varint_size_test.cc
new file mode 100644
index 000000000..246b26582
--- /dev/null
+++ b/pw_protobuf/varint_size_test.cc
@@ -0,0 +1,73 @@
+// Copyright 2021 The Pigweed Authors
+//
+// 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
+//
+//     https://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.
+
+#include "gtest/gtest.h"
+#include "pw_bytes/array.h"
+#include "pw_protobuf/encoder.h"
+
+namespace pw::protobuf {
+namespace {
+
+TEST(Encoder, SizeTypeIsConfigured) {
+  static_assert(sizeof(Encoder::SizeType) == sizeof(uint8_t));
+}
+
+TEST(Encoder, NestedWriteSmallerThanVarintSize) {
+  std::array<std::byte, 256> buffer;
+  NestedEncoder<2, 2> encoder(buffer);
+
+  encoder.Push(1);
+  // 1 byte key + 1 byte size + 125 byte value = 127 byte nested length.
+  EXPECT_EQ(encoder.WriteBytes(2, bytes::Initialized<125>(0xaa)), OkStatus());
+  encoder.Pop();
+
+  auto result = encoder.Encode();
+  EXPECT_EQ(result.status(), OkStatus());
+}
+
+TEST(Encoder, NestedWriteLargerThanVarintSizeReturnsOutOfRange) {
+  std::array<std::byte, 256> buffer;
+  NestedEncoder<2, 2> encoder(buffer);
+
+  // Try to write a larger nested message than the max nested varint value.
+  encoder.Push(1);
+  // 1 byte key + 1 byte size + 126 byte value = 128 byte nested length.
+  EXPECT_EQ(encoder.WriteBytes(2, bytes::Initialized<126>(0xaa)),
+            Status::OutOfRange());
+  EXPECT_EQ(encoder.WriteUint32(3, 42), Status::OutOfRange());
+  encoder.Pop();
+
+  auto result = encoder.Encode();
+  EXPECT_EQ(result.status(), Status::OutOfRange());
+}
+
+TEST(Encoder, NestedMessageLargerThanVarintSizeReturnsOutOfRange) {
+  std::array<std::byte, 256> buffer;
+  NestedEncoder<2, 2> encoder(buffer);
+
+  // Try to write a larger nested message than the max nested varint value as
+  // multiple smaller writes.
+  encoder.Push(1);
+  EXPECT_EQ(encoder.WriteBytes(2, bytes::Initialized<60>(0xaa)), OkStatus());
+  EXPECT_EQ(encoder.WriteBytes(3, bytes::Initialized<60>(0xaa)), OkStatus());
+  EXPECT_EQ(encoder.WriteBytes(4, bytes::Initialized<60>(0xaa)),
+            Status::OutOfRange());
+  encoder.Pop();
+
+  auto result = encoder.Encode();
+  EXPECT_EQ(result.status(), Status::OutOfRange());
+}
+
+}  // namespace
+}  // namespace pw::protobuf