fmt/test/gtest-extra.h

// Formatting library for C++ - custom Google Test assertions
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.

#ifndef FMT_GTEST_EXTRA_H_
#define FMT_GTEST_EXTRA_H_

#include <string>
#include "gmock.h"

#include "fmt/core.h"

#ifndef FMT_USE_FILE_DESCRIPTORS
# define FMT_USE_FILE_DESCRIPTORS 0
#endif

#if FMT_USE_FILE_DESCRIPTORS
# include "fmt/posix.h"
#endif

#define FMT_TEST_THROW_(statement, expected_exception, expected_message, fail) \
  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
  if (::testing::AssertionResult gtest_ar = ::testing::AssertionSuccess()) { \
    std::string gtest_expected_message = expected_message; \
    bool gtest_caught_expected = false; \
    try { \
      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
    } \
    catch (expected_exception const& e) { \
      if (gtest_expected_message != e.what()) { \
        gtest_ar \
          << #statement " throws an exception with a different message.\n" \
          << "Expected: " << gtest_expected_message << "\n" \
          << "  Actual: " << e.what(); \
        goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__); \
      } \
      gtest_caught_expected = true; \
    } \
    catch (...) { \
      gtest_ar << \
          "Expected: " #statement " throws an exception of type " \
          #expected_exception ".\n  Actual: it throws a different type."; \
      goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__); \
    } \
    if (!gtest_caught_expected) { \
      gtest_ar << \
          "Expected: " #statement " throws an exception of type " \
          #expected_exception ".\n  Actual: it throws nothing."; \
      goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__); \
    } \
  } else \
    GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__): \
      fail(gtest_ar.failure_message())

// Tests that the statement throws the expected exception and the exception's
// what() method returns expected message.
#define EXPECT_THROW_MSG(statement, expected_exception, expected_message) \
  FMT_TEST_THROW_(statement, expected_exception, \
      expected_message, GTEST_NONFATAL_FAILURE_)

std::string format_system_error(int error_code, fmt::string_view message);

#define EXPECT_SYSTEM_ERROR(statement, error_code, message) \
  EXPECT_THROW_MSG(statement, fmt::system_error, \
      format_system_error(error_code, message))

#if FMT_USE_FILE_DESCRIPTORS

// Captures file output by redirecting it to a pipe.
// The output it can handle is limited by the pipe capacity.
class OutputRedirect {
 private:
  FILE *file_;
  fmt::file original_;  // Original file passed to redirector.
  fmt::file read_end_;  // Read end of the pipe where the output is redirected.

  GTEST_DISALLOW_COPY_AND_ASSIGN_(OutputRedirect);

  void flush();
  void restore();

 public:
  explicit OutputRedirect(FILE *file);
  ~OutputRedirect() FMT_NOEXCEPT;

  // Restores the original file, reads output from the pipe into a string
  // and returns it.
  std::string restore_and_read();
};

#define FMT_TEST_WRITE_(statement, expected_output, file, fail) \
  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
  if (::testing::AssertionResult gtest_ar = ::testing::AssertionSuccess()) { \
    std::string gtest_expected_output = expected_output; \
    OutputRedirect gtest_redir(file); \
    GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
    std::string gtest_output = gtest_redir.restore_and_read(); \
    if (gtest_output != gtest_expected_output) { \
      gtest_ar \
        << #statement " produces different output.\n" \
        << "Expected: " << gtest_expected_output << "\n" \
        << "  Actual: " << gtest_output; \
      goto GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__); \
    } \
  } else \
    GTEST_CONCAT_TOKEN_(gtest_label_testthrow_, __LINE__): \
      fail(gtest_ar.failure_message())

// Tests that the statement writes the expected output to file.
#define EXPECT_WRITE(file, statement, expected_output) \
    FMT_TEST_WRITE_(statement, expected_output, file, GTEST_NONFATAL_FAILURE_)

#ifdef _MSC_VER

// Suppresses Windows assertions on invalid file descriptors, making
// POSIX functions return proper error codes instead of crashing on Windows.
class SuppressAssert {
 private:
  _invalid_parameter_handler original_handler_;
  int original_report_mode_;

  static void handle_invalid_parameter(const wchar_t *,
      const wchar_t *, const wchar_t *, unsigned , uintptr_t) {}

 public:
  SuppressAssert()
  : original_handler_(_set_invalid_parameter_handler(handle_invalid_parameter)),
    original_report_mode_(_CrtSetReportMode(_CRT_ASSERT, 0)) {
  }
  ~SuppressAssert() {
    _set_invalid_parameter_handler(original_handler_);
    _CrtSetReportMode(_CRT_ASSERT, original_report_mode_);
  }
};

# define SUPPRESS_ASSERT(statement) { SuppressAssert sa; statement; }
#else
# define SUPPRESS_ASSERT(statement) statement
#endif  // _MSC_VER

#define EXPECT_SYSTEM_ERROR_NOASSERT(statement, error_code, message) \
  EXPECT_SYSTEM_ERROR(SUPPRESS_ASSERT(statement), error_code, message)

// Attempts to read count characters from a file.
std::string read(fmt::file &f, std::size_t count);

#define EXPECT_READ(file, expected_content) \
  EXPECT_EQ(expected_content, read(file, std::strlen(expected_content)))

#endif  // FMT_USE_FILE_DESCRIPTORS

template <typename Mock>
struct ScopedMock : testing::StrictMock<Mock> {
  ScopedMock() { Mock::instance = this; }
  ~ScopedMock() { Mock::instance = nullptr; }
};

#endif  // FMT_GTEST_EXTRA_H_