pw_protobuf/encoder_test.cc - pigweed/pigweed - Git at Google

 // Copyright 2019 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 "pw_protobuf/encoder.h"

 #include "gtest/gtest.h"

 namespace pw::protobuf {
 namespace {

 // The tests in this file use the following proto message schemas.
 //
 //   message TestProto {
 //     uint32 magic_number = 1;
 //     sint32 ziggy = 2;
 //     fixed64 cycles = 3;
 //     float ratio = 4;
 //     string error_message = 5;
 //     NestedProto nested = 6;
 //   }
 //
 //   message NestedProto {
 //     string hello = 1;
 //     uint32 id = 2;
 //     repeated DoubleNestedProto pair = 3;
 //   }
 //
 //   message DoubleNestedProto {
 //     string key = 1;
 //     string value = 2;
 //   }
 //

 constexpr uint32_t kTestProtoMagicNumberField = 1;
 constexpr uint32_t kTestProtoZiggyField = 2;
 constexpr uint32_t kTestProtoCyclesField = 3;
 constexpr uint32_t kTestProtoRatioField = 4;
 constexpr uint32_t kTestProtoErrorMessageField = 5;
 constexpr uint32_t kTestProtoNestedField = 6;

 constexpr uint32_t kNestedProtoHelloField = 1;
 constexpr uint32_t kNestedProtoIdField = 2;
 constexpr uint32_t kNestedProtoPairField = 3;

 constexpr uint32_t kDoubleNestedProtoKeyField = 1;
 constexpr uint32_t kDoubleNestedProtoValueField = 2;

 TEST(Encoder, EncodePrimitives) {
   // TestProto tp;
   // tp.magic_number = 42;
   // tp.ziggy = -13;
   // tp.cycles = 0xdeadbeef8badf00d;
   // tp.ratio = 1.618034;
   // tp.error_message = "broken 💩";

   // Hand-encoded version of the above.
   // clang-format off
   constexpr uint8_t encoded_proto[] = {
     // magic_number [varint k=1]
     0x08, 0x2a,
     // ziggy [varint k=2]
     0x10, 0x19,
     // cycles [fixed64 k=3]
     0x19, 0x0d, 0xf0, 0xad, 0x8b, 0xef, 0xbe, 0xad, 0xde,
     // ratio [fixed32 k=4]
     0x25, 0xbd, 0x1b, 0xcf, 0x3f,
     // error_message [delimited k=5],
     0x2a, 0x0b, 'b', 'r', 'o', 'k', 'e', 'n', ' ',
     // poop!
     0xf0, 0x9f, 0x92, 0xa9,
   };
   // clang-format on

   std::byte encode_buffer[32];
   NestedEncoder encoder(encode_buffer);

   EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);
   EXPECT_EQ(encoder.WriteSint32(kTestProtoZiggyField, -13), Status::OK);
   EXPECT_EQ(encoder.WriteFixed64(kTestProtoCyclesField, 0xdeadbeef8badf00d),
             Status::OK);
   EXPECT_EQ(encoder.WriteFloat(kTestProtoRatioField, 1.618034), Status::OK);
   EXPECT_EQ(encoder.WriteString(kTestProtoErrorMessageField, "broken 💩"),
             Status::OK);

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
   EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
   EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
 }

 TEST(Encoder, EncodeInsufficientSpace) {
   std::byte encode_buffer[12];
   NestedEncoder encoder(encode_buffer);

   // 2 bytes.
   EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);
   // 2 bytes.
   EXPECT_EQ(encoder.WriteSint32(kTestProtoZiggyField, -13), Status::OK);
   // 9 bytes; not enough space! The encoder will start writing the field but
   // should rollback when it realizes it doesn't have enough space.
   EXPECT_EQ(encoder.WriteFixed64(kTestProtoCyclesField, 0xdeadbeef8badf00d),
             Status::RESOURCE_EXHAUSTED);
   // Any further write operations should fail.
   EXPECT_EQ(encoder.WriteFloat(kTestProtoRatioField, 1.618034),
             Status::RESOURCE_EXHAUSTED);

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::RESOURCE_EXHAUSTED);
   EXPECT_EQ(encoded.size(), 0u);
 }

 TEST(Encoder, EncodeInvalidArguments) {
   std::byte encode_buffer[12];
   NestedEncoder encoder(encode_buffer);

   EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);
   // Invalid proto field numbers.
   EXPECT_EQ(encoder.WriteUint32(0, 1337), Status::INVALID_ARGUMENT);
   encoder.Clear();

   EXPECT_EQ(encoder.WriteString(1u << 31, "ha"), Status::INVALID_ARGUMENT);
   encoder.Clear();

   EXPECT_EQ(encoder.WriteBool(19091, false), Status::INVALID_ARGUMENT);
   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::INVALID_ARGUMENT);
   EXPECT_EQ(encoded.size(), 0u);
 }

 TEST(Encoder, Nested) {
   std::byte encode_buffer[128];
   NestedEncoder<5, 10> encoder(encode_buffer);

   // TestProto test_proto;
   // test_proto.magic_number = 42;
   EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);

   {
     // NestedProto& nested_proto = test_proto.nested;
     EXPECT_EQ(encoder.Push(kTestProtoNestedField), Status::OK);
     // nested_proto.hello = "world";
     EXPECT_EQ(encoder.WriteString(kNestedProtoHelloField, "world"), Status::OK);
     // nested_proto.id = 999;
     EXPECT_EQ(encoder.WriteUint32(kNestedProtoIdField, 999), Status::OK);

     {
       // DoubleNestedProto& double_nested_proto = nested_proto.append_pair();
       EXPECT_EQ(encoder.Push(kNestedProtoPairField), Status::OK);
       // double_nested_proto.key = "version";
       EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoKeyField, "version"),
                 Status::OK);
       // double_nested_proto.value = "2.9.1";
       EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoValueField, "2.9.1"),
                 Status::OK);

       EXPECT_EQ(encoder.Pop(), Status::OK);
     }  // end DoubleNestedProto

     {
       // DoubleNestedProto& double_nested_proto = nested_proto.append_pair();
       EXPECT_EQ(encoder.Push(kNestedProtoPairField), Status::OK);
       // double_nested_proto.key = "device";
       EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoKeyField, "device"),
                 Status::OK);
       // double_nested_proto.value = "left-soc";
       EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoValueField, "left-soc"),
                 Status::OK);

       EXPECT_EQ(encoder.Pop(), Status::OK);
     }  // end DoubleNestedProto

     EXPECT_EQ(encoder.Pop(), Status::OK);
   }  // end NestedProto

   // test_proto.ziggy = -13;
   EXPECT_EQ(encoder.WriteSint32(kTestProtoZiggyField, -13), Status::OK);

   // clang-format off
   constexpr uint8_t encoded_proto[] = {
     // magic_number
     0x08, 0x2a,
     // nested header (key, size)
     0x32, 0x30,
     // nested.hello
     0x0a, 0x05, 'w', 'o', 'r', 'l', 'd',
     // nested.id
     0x10, 0xe7, 0x07,
     // nested.pair[0] header (key, size)
     0x1a, 0x10,
     // nested.pair[0].key
     0x0a, 0x07, 'v', 'e', 'r', 's', 'i', 'o', 'n',
     // nested.pair[0].value
     0x12, 0x05, '2', '.', '9', '.', '1',
     // nested.pair[1] header (key, size)
     0x1a, 0x12,
     // nested.pair[1].key
     0x0a, 0x06, 'd', 'e', 'v', 'i', 'c', 'e',
     // nested.pair[1].value
     0x12, 0x08, 'l', 'e', 'f', 't', '-', 's', 'o', 'c',
     // ziggy
     0x10, 0x19
   };
   // clang-format on

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
   EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
   EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
 }

 TEST(Encoder, NestedDepthLimit) {
   std::byte encode_buffer[128];
   NestedEncoder<2, 10> encoder(encode_buffer);

   // One level of nesting.
   EXPECT_EQ(encoder.Push(2), Status::OK);
   // Two levels of nesting.
   EXPECT_EQ(encoder.Push(1), Status::OK);
   // Three levels of nesting: error!
   EXPECT_EQ(encoder.Push(1), Status::RESOURCE_EXHAUSTED);

   // Further operations should fail.
   EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
   EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
   EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
 }

 TEST(Encoder, NestedBlobLimit) {
   std::byte encode_buffer[128];
   NestedEncoder<5, 3> encoder(encode_buffer);

   // Write first blob.
   EXPECT_EQ(encoder.Push(1), Status::OK);
   EXPECT_EQ(encoder.Pop(), Status::OK);

   // Write second blob.
   EXPECT_EQ(encoder.Push(2), Status::OK);

   // Write nested third blob.
   EXPECT_EQ(encoder.Push(3), Status::OK);
   EXPECT_EQ(encoder.Pop(), Status::OK);

   // End second blob.
   EXPECT_EQ(encoder.Pop(), Status::OK);

   // Write fourth blob: error!.
   EXPECT_EQ(encoder.Push(4), Status::RESOURCE_EXHAUSTED);
   // Nothing to pop.
   EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
 }

 TEST(Encoder, RepeatedField) {
   std::byte encode_buffer[32];
   NestedEncoder encoder(encode_buffer);

   // repeated uint32 values = 1;
   constexpr uint32_t values[] = {0, 50, 100, 150, 200};
   for (int i = 0; i < 5; ++i) {
     encoder.WriteUint32(1, values[i]);
   }

   constexpr uint8_t encoded_proto[] = {
       0x08, 0x00, 0x08, 0x32, 0x08, 0x64, 0x08, 0x96, 0x01, 0x08, 0xc8, 0x01};

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
   EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
   EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
 }

 TEST(Encoder, PackedVarint) {
   std::byte encode_buffer[32];
   NestedEncoder encoder(encode_buffer);

   // repeated uint32 values = 1;
   constexpr uint32_t values[] = {0, 50, 100, 150, 200};
   encoder.WritePackedUint32(1, values);

   constexpr uint8_t encoded_proto[] = {
       0x0a, 0x07, 0x00, 0x32, 0x64, 0x96, 0x01, 0xc8, 0x01};
   //  key   size  v[0]  v[1]  v[2]  v[3]        v[4]

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
   EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
   EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
 }

 TEST(Encoder, PackedVarintInsufficientSpace) {
   std::byte encode_buffer[8];
   NestedEncoder encoder(encode_buffer);

   constexpr uint32_t values[] = {0, 50, 100, 150, 200};
   encoder.WritePackedUint32(1, values);

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::RESOURCE_EXHAUSTED);
   EXPECT_EQ(encoded.size(), 0u);
 }

 TEST(Encoder, PackedFixed) {
   std::byte encode_buffer[32];
   NestedEncoder encoder(encode_buffer);

   // repeated fixed32 values = 1;
   constexpr uint32_t values[] = {0, 50, 100, 150, 200};
   encoder.WritePackedFixed32(1, values);

   // repeated fixed64 values64 = 2;
   constexpr uint64_t values64[] = {0x0102030405060708};
   encoder.WritePackedFixed64(2, values64);

   constexpr uint8_t encoded_proto[] = {
       0x0a, 0x14, 0x00, 0x00, 0x00, 0x00, 0x32, 0x00, 0x00, 0x00, 0x64,
       0x00, 0x00, 0x00, 0x96, 0x00, 0x00, 0x00, 0xc8, 0x00, 0x00, 0x00,
       0x12, 0x08, 0x08, 0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01};

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
   EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
   EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
 }

 TEST(Encoder, PackedZigzag) {
   std::byte encode_buffer[32];
   NestedEncoder encoder(encode_buffer);

   // repeated sint32 values = 1;
   constexpr int32_t values[] = {-100, -25, -1, 0, 1, 25, 100};
   encoder.WritePackedSint32(1, values);

   constexpr uint8_t encoded_proto[] = {
       0x0a, 0x09, 0xc7, 0x01, 0x31, 0x01, 0x00, 0x02, 0x32, 0xc8, 0x01};

   std::span<const std::byte> encoded;
   EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
   EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
   EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
 }

 }  // namespace
 }  // namespace pw::protobuf
	// Copyright 2019 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 "pw_protobuf/encoder.h"

	#include "gtest/gtest.h"

	namespace pw::protobuf {
	namespace {

	// The tests in this file use the following proto message schemas.
	//
	// message TestProto {
	// uint32 magic_number = 1;
	// sint32 ziggy = 2;
	// fixed64 cycles = 3;
	// float ratio = 4;
	// string error_message = 5;
	// NestedProto nested = 6;
	// }
	//
	// message NestedProto {
	// string hello = 1;
	// uint32 id = 2;
	// repeated DoubleNestedProto pair = 3;
	// }
	//
	// message DoubleNestedProto {
	// string key = 1;
	// string value = 2;
	// }
	//

	constexpr uint32_t kTestProtoMagicNumberField = 1;
	constexpr uint32_t kTestProtoZiggyField = 2;
	constexpr uint32_t kTestProtoCyclesField = 3;
	constexpr uint32_t kTestProtoRatioField = 4;
	constexpr uint32_t kTestProtoErrorMessageField = 5;
	constexpr uint32_t kTestProtoNestedField = 6;

	constexpr uint32_t kNestedProtoHelloField = 1;
	constexpr uint32_t kNestedProtoIdField = 2;
	constexpr uint32_t kNestedProtoPairField = 3;

	constexpr uint32_t kDoubleNestedProtoKeyField = 1;
	constexpr uint32_t kDoubleNestedProtoValueField = 2;

	TEST(Encoder, EncodePrimitives) {
	// TestProto tp;
	// tp.magic_number = 42;
	// tp.ziggy = -13;
	// tp.cycles = 0xdeadbeef8badf00d;
	// tp.ratio = 1.618034;
	// tp.error_message = "broken 💩";

	// Hand-encoded version of the above.
	// clang-format off
	constexpr uint8_t encoded_proto[] = {
	// magic_number [varint k=1]
	0x08, 0x2a,
	// ziggy [varint k=2]
	0x10, 0x19,
	// cycles [fixed64 k=3]
	0x19, 0x0d, 0xf0, 0xad, 0x8b, 0xef, 0xbe, 0xad, 0xde,
	// ratio [fixed32 k=4]
	0x25, 0xbd, 0x1b, 0xcf, 0x3f,
	// error_message [delimited k=5],
	0x2a, 0x0b, 'b', 'r', 'o', 'k', 'e', 'n', ' ',
	// poop!
	0xf0, 0x9f, 0x92, 0xa9,
	};
	// clang-format on

	std::byte encode_buffer[32];
	NestedEncoder encoder(encode_buffer);

	EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);
	EXPECT_EQ(encoder.WriteSint32(kTestProtoZiggyField, -13), Status::OK);
	EXPECT_EQ(encoder.WriteFixed64(kTestProtoCyclesField, 0xdeadbeef8badf00d),
	Status::OK);
	EXPECT_EQ(encoder.WriteFloat(kTestProtoRatioField, 1.618034), Status::OK);
	EXPECT_EQ(encoder.WriteString(kTestProtoErrorMessageField, "broken 💩"),
	Status::OK);

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
	EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
	EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
	}

	TEST(Encoder, EncodeInsufficientSpace) {
	std::byte encode_buffer[12];
	NestedEncoder encoder(encode_buffer);

	// 2 bytes.
	EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);
	// 2 bytes.
	EXPECT_EQ(encoder.WriteSint32(kTestProtoZiggyField, -13), Status::OK);
	// 9 bytes; not enough space! The encoder will start writing the field but
	// should rollback when it realizes it doesn't have enough space.
	EXPECT_EQ(encoder.WriteFixed64(kTestProtoCyclesField, 0xdeadbeef8badf00d),
	Status::RESOURCE_EXHAUSTED);
	// Any further write operations should fail.
	EXPECT_EQ(encoder.WriteFloat(kTestProtoRatioField, 1.618034),
	Status::RESOURCE_EXHAUSTED);

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::RESOURCE_EXHAUSTED);
	EXPECT_EQ(encoded.size(), 0u);
	}

	TEST(Encoder, EncodeInvalidArguments) {
	std::byte encode_buffer[12];
	NestedEncoder encoder(encode_buffer);

	EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);
	// Invalid proto field numbers.
	EXPECT_EQ(encoder.WriteUint32(0, 1337), Status::INVALID_ARGUMENT);
	encoder.Clear();

	EXPECT_EQ(encoder.WriteString(1u << 31, "ha"), Status::INVALID_ARGUMENT);
	encoder.Clear();

	EXPECT_EQ(encoder.WriteBool(19091, false), Status::INVALID_ARGUMENT);
	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::INVALID_ARGUMENT);
	EXPECT_EQ(encoded.size(), 0u);
	}

	TEST(Encoder, Nested) {
	std::byte encode_buffer[128];
	NestedEncoder<5, 10> encoder(encode_buffer);

	// TestProto test_proto;
	// test_proto.magic_number = 42;
	EXPECT_EQ(encoder.WriteUint32(kTestProtoMagicNumberField, 42), Status::OK);

	{
	// NestedProto& nested_proto = test_proto.nested;
	EXPECT_EQ(encoder.Push(kTestProtoNestedField), Status::OK);
	// nested_proto.hello = "world";
	EXPECT_EQ(encoder.WriteString(kNestedProtoHelloField, "world"), Status::OK);
	// nested_proto.id = 999;
	EXPECT_EQ(encoder.WriteUint32(kNestedProtoIdField, 999), Status::OK);

	{
	// DoubleNestedProto& double_nested_proto = nested_proto.append_pair();
	EXPECT_EQ(encoder.Push(kNestedProtoPairField), Status::OK);
	// double_nested_proto.key = "version";
	EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoKeyField, "version"),
	Status::OK);
	// double_nested_proto.value = "2.9.1";
	EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoValueField, "2.9.1"),
	Status::OK);

	EXPECT_EQ(encoder.Pop(), Status::OK);
	} // end DoubleNestedProto

	{
	// DoubleNestedProto& double_nested_proto = nested_proto.append_pair();
	EXPECT_EQ(encoder.Push(kNestedProtoPairField), Status::OK);
	// double_nested_proto.key = "device";
	EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoKeyField, "device"),
	Status::OK);
	// double_nested_proto.value = "left-soc";
	EXPECT_EQ(encoder.WriteString(kDoubleNestedProtoValueField, "left-soc"),
	Status::OK);

	EXPECT_EQ(encoder.Pop(), Status::OK);
	} // end DoubleNestedProto

	EXPECT_EQ(encoder.Pop(), Status::OK);
	} // end NestedProto

	// test_proto.ziggy = -13;
	EXPECT_EQ(encoder.WriteSint32(kTestProtoZiggyField, -13), Status::OK);

	// clang-format off
	constexpr uint8_t encoded_proto[] = {
	// magic_number
	0x08, 0x2a,
	// nested header (key, size)
	0x32, 0x30,
	// nested.hello
	0x0a, 0x05, 'w', 'o', 'r', 'l', 'd',
	// nested.id
	0x10, 0xe7, 0x07,
	// nested.pair[0] header (key, size)
	0x1a, 0x10,
	// nested.pair[0].key
	0x0a, 0x07, 'v', 'e', 'r', 's', 'i', 'o', 'n',
	// nested.pair[0].value
	0x12, 0x05, '2', '.', '9', '.', '1',
	// nested.pair[1] header (key, size)
	0x1a, 0x12,
	// nested.pair[1].key
	0x0a, 0x06, 'd', 'e', 'v', 'i', 'c', 'e',
	// nested.pair[1].value
	0x12, 0x08, 'l', 'e', 'f', 't', '-', 's', 'o', 'c',
	// ziggy
	0x10, 0x19
	};
	// clang-format on

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
	EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
	EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
	}

	TEST(Encoder, NestedDepthLimit) {
	std::byte encode_buffer[128];
	NestedEncoder<2, 10> encoder(encode_buffer);

	// One level of nesting.
	EXPECT_EQ(encoder.Push(2), Status::OK);
	// Two levels of nesting.
	EXPECT_EQ(encoder.Push(1), Status::OK);
	// Three levels of nesting: error!
	EXPECT_EQ(encoder.Push(1), Status::RESOURCE_EXHAUSTED);

	// Further operations should fail.
	EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
	EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
	EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
	}

	TEST(Encoder, NestedBlobLimit) {
	std::byte encode_buffer[128];
	NestedEncoder<5, 3> encoder(encode_buffer);

	// Write first blob.
	EXPECT_EQ(encoder.Push(1), Status::OK);
	EXPECT_EQ(encoder.Pop(), Status::OK);

	// Write second blob.
	EXPECT_EQ(encoder.Push(2), Status::OK);

	// Write nested third blob.
	EXPECT_EQ(encoder.Push(3), Status::OK);
	EXPECT_EQ(encoder.Pop(), Status::OK);

	// End second blob.
	EXPECT_EQ(encoder.Pop(), Status::OK);

	// Write fourth blob: error!.
	EXPECT_EQ(encoder.Push(4), Status::RESOURCE_EXHAUSTED);
	// Nothing to pop.
	EXPECT_EQ(encoder.Pop(), Status::RESOURCE_EXHAUSTED);
	}

	TEST(Encoder, RepeatedField) {
	std::byte encode_buffer[32];
	NestedEncoder encoder(encode_buffer);

	// repeated uint32 values = 1;
	constexpr uint32_t values[] = {0, 50, 100, 150, 200};
	for (int i = 0; i < 5; ++i) {
	encoder.WriteUint32(1, values[i]);
	}

	constexpr uint8_t encoded_proto[] = {
	0x08, 0x00, 0x08, 0x32, 0x08, 0x64, 0x08, 0x96, 0x01, 0x08, 0xc8, 0x01};

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
	EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
	EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
	}

	TEST(Encoder, PackedVarint) {
	std::byte encode_buffer[32];
	NestedEncoder encoder(encode_buffer);

	// repeated uint32 values = 1;
	constexpr uint32_t values[] = {0, 50, 100, 150, 200};
	encoder.WritePackedUint32(1, values);

	constexpr uint8_t encoded_proto[] = {
	0x0a, 0x07, 0x00, 0x32, 0x64, 0x96, 0x01, 0xc8, 0x01};
	// key size v[0] v[1] v[2] v[3] v[4]

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
	EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
	EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
	}

	TEST(Encoder, PackedVarintInsufficientSpace) {
	std::byte encode_buffer[8];
	NestedEncoder encoder(encode_buffer);

	constexpr uint32_t values[] = {0, 50, 100, 150, 200};
	encoder.WritePackedUint32(1, values);

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::RESOURCE_EXHAUSTED);
	EXPECT_EQ(encoded.size(), 0u);
	}

	TEST(Encoder, PackedFixed) {
	std::byte encode_buffer[32];
	NestedEncoder encoder(encode_buffer);

	// repeated fixed32 values = 1;
	constexpr uint32_t values[] = {0, 50, 100, 150, 200};
	encoder.WritePackedFixed32(1, values);

	// repeated fixed64 values64 = 2;
	constexpr uint64_t values64[] = {0x0102030405060708};
	encoder.WritePackedFixed64(2, values64);

	constexpr uint8_t encoded_proto[] = {
	0x0a, 0x14, 0x00, 0x00, 0x00, 0x00, 0x32, 0x00, 0x00, 0x00, 0x64,
	0x00, 0x00, 0x00, 0x96, 0x00, 0x00, 0x00, 0xc8, 0x00, 0x00, 0x00,
	0x12, 0x08, 0x08, 0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01};

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
	EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
	EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
	}

	TEST(Encoder, PackedZigzag) {
	std::byte encode_buffer[32];
	NestedEncoder encoder(encode_buffer);

	// repeated sint32 values = 1;
	constexpr int32_t values[] = {-100, -25, -1, 0, 1, 25, 100};
	encoder.WritePackedSint32(1, values);

	constexpr uint8_t encoded_proto[] = {
	0x0a, 0x09, 0xc7, 0x01, 0x31, 0x01, 0x00, 0x02, 0x32, 0xc8, 0x01};

	std::span<const std::byte> encoded;
	EXPECT_EQ(encoder.Encode(&encoded), Status::OK);
	EXPECT_EQ(encoded.size(), sizeof(encoded_proto));
	EXPECT_EQ(std::memcmp(encoded.data(), encoded_proto, encoded.size()), 0);
	}

	} // namespace
	} // namespace pw::protobuf