fmt/test/gtest-extra.h

/*
 Custom Google Test assertions.

 Copyright (c) 2012-2014, Victor Zverovich
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:

 1. Redistributions of source code must retain the above copyright notice, this
    list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef FMT_GTEST_EXTRA_H
#define FMT_GTEST_EXTRA_H

#include <string>
#include <gtest/gtest.h>

#include "format.h"

#ifndef FMT_USE_FILE_DESCRIPTORS
# define FMT_USE_FILE_DESCRIPTORS 0
#endif

#if FMT_USE_FILE_DESCRIPTORS
# include "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::StringRef message);

#define EXPECT_SYSTEM_ERROR(statement, error_code, message) \
  EXPECT_THROW_MSG(statement, fmt::SystemError, \
      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(true);

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

#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.RestoreAndRead(); \
    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_)

#endif  // FMT_USE_FILE_DESCRIPTORS

#endif  // FMT_GTEST_EXTRA_H