[protocol] Add unittest for libhoth_payload_update_read_chunk (#241)

This function is being used within libhoth host command and needs a
check.

Signed-off-by: Ellis Nguyen <sarzanguyen@google.com>

Author: esnguyen

protocol/payload_update_test.cc

@@ -16,9 +16,13 @@
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
+#include <unistd.h>
 
 #include <cstdint>
+#include <cstdlib>
+#include <cstring>
 #include <memory>
+#include <string>
 
 #include "command_version.h"
 #include "payload_info.h"
@@ -38,15 +42,35 @@ constexpr int64_t kAlign = 1 << 16;
 constexpr int64_t kDummy = 0;
 
 MATCHER_P2(IsEraseRequest, offset, len, "") {
-  const uint8_t* data = static_cast<const uint8_t*>(arg);
+  const struct hoth_host_request* req =
+      static_cast<const struct hoth_host_request*>(arg);
+  if (req->struct_version != HOTH_HOST_REQUEST_VERSION ||
+      req->command != kCmd) {
+    return false;
+  }
   const struct payload_update_packet* p =
       reinterpret_cast<const struct payload_update_packet*>(
-          data + sizeof(struct hoth_host_request));
+          static_cast<const uint8_t*>(arg) + sizeof(struct hoth_host_request));
   return p->type == PAYLOAD_UPDATE_ERASE &&
          p->offset == static_cast<uint32_t>(offset) &&
          p->len == static_cast<uint32_t>(len);
 }
 
+MATCHER_P2(IsReadRequest, offset, len, "") {
+  const struct hoth_host_request* req =
+      static_cast<const struct hoth_host_request*>(arg);
+  if (req->struct_version != HOTH_HOST_REQUEST_VERSION ||
+      req->command != kCmd) {
+    return false;
+  }
+  const struct payload_update_packet* p =
+      reinterpret_cast<const struct payload_update_packet*>(
+          static_cast<const uint8_t*>(arg) + sizeof(struct hoth_host_request));
+  return p->type == PAYLOAD_UPDATE_READ &&
+         p->offset == static_cast<uint32_t>(offset) &&
+         p->len == static_cast<uint32_t>(len);
+}
+
 TEST_F(LibHothTest, payload_update_bad_image_test) {
   EXPECT_CALL(mock_, send(_, UsesCommand(kCmd), _))
       .WillRepeatedly(Return(LIBHOTH_OK));
@@ -496,3 +520,31 @@ TEST_F(LibHothTest, payload_update_erase_cmd_range_overflow_test) {
   EXPECT_EQ(libhoth_payload_update_erase(&hoth_dev_, kOffset, kSize),
             PAYLOAD_UPDATE_INVALID_ARGS);
 }
+
+TEST_F(LibHothTest, payload_update_read_chunk_test) {
+  uint8_t expected_data[] = {0x11, 0x22, 0x33, 0x44, 0x55};
+  size_t offset = 0x100;
+  size_t len = sizeof(expected_data);
+
+  EXPECT_CALL(mock_, send(_, IsReadRequest(offset, len), _))
+      .WillOnce(Return(LIBHOTH_OK));
+  EXPECT_CALL(mock_, receive)
+      .WillOnce(DoAll(CopyResp(expected_data, len), Return(LIBHOTH_OK)));
+
+  std::string temp_path = testing::TempDir() + "libhoth_payload_read_XXXXXX";
+  int fd = mkstemp(&temp_path[0]);
+  ASSERT_GE(fd, 0);
+  unlink(temp_path.c_str());
+  struct FdGuard {
+    int fd;
+    ~FdGuard() { close(fd); }
+  } guard = {fd};
+
+  EXPECT_EQ(libhoth_payload_update_read_chunk(&hoth_dev_, fd, len, offset),
+            PAYLOAD_UPDATE_OK);
+
+  ASSERT_EQ(lseek(fd, 0, SEEK_SET), 0);
+  uint8_t actual_data[sizeof(expected_data)] = {0};
+  ASSERT_EQ(read(fd, actual_data, len), static_cast<ssize_t>(len));
+  EXPECT_THAT(actual_data, ::testing::ElementsAreArray(expected_data));
+}