libc/test/src/stdio/fgetc_test.cpp

//===-- Unittests for fgetc -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "src/__support/CPP/scope.h"
#include "src/stdio/clearerr.h"
#include "src/stdio/fclose.h"
#include "src/stdio/feof.h"
#include "src/stdio/ferror.h"
#include "src/stdio/fgetc.h"
#include "src/stdio/fopen.h"
#include "src/stdio/fwrite.h"
#include "src/stdio/getc.h"
#include "test/UnitTest/ErrnoCheckingTest.h"
#include "test/UnitTest/ErrnoSetterMatcher.h"
#include "test/UnitTest/Test.h"

#include "hdr/stdio_macros.h"

using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
using LIBC_NAMESPACE::cpp::scope_exit;

class LlvmLibcGetcTest : public LIBC_NAMESPACE::testing::ErrnoCheckingTest {
public:
  using GetcFunc = int(FILE *);
  void test_with_func(GetcFunc *func, const char *filename) {
    constexpr char CONTENT[] = "123456789";
    constexpr size_t WRITE_SIZE = sizeof(CONTENT) - 1;

    {
      ::FILE *file = LIBC_NAMESPACE::fopen(filename, "w");
      ASSERT_FALSE(file == nullptr);
      scope_exit close_file(
          [&] { ASSERT_THAT(LIBC_NAMESPACE::fclose(file), Succeeds()); });

      ASSERT_THAT(LIBC_NAMESPACE::fwrite(CONTENT, 1, WRITE_SIZE, file),
                  Succeeds(WRITE_SIZE));
      // This is a write-only file so reads should fail.
      ASSERT_THAT(func(file), Fails(EBADF, EOF));
      // This is an error and not a real EOF.
      ASSERT_EQ(LIBC_NAMESPACE::feof(file), 0);
      ASSERT_NE(LIBC_NAMESPACE::ferror(file), 0);
    }

    {
      ::FILE *file = LIBC_NAMESPACE::fopen(filename, "r");
      ASSERT_FALSE(file == nullptr);
      scope_exit close_file(
          [&] { ASSERT_THAT(LIBC_NAMESPACE::fclose(file), Succeeds()); });

      for (size_t i = 0; i < WRITE_SIZE; ++i) {
        ASSERT_THAT(func(file), Succeeds(int('1' + i)));
      }
      // Reading more should return EOF but not set error.
      ASSERT_THAT(func(file), Succeeds(EOF));
      ASSERT_NE(LIBC_NAMESPACE::feof(file), 0);
      ASSERT_EQ(LIBC_NAMESPACE::ferror(file), 0);
    }
  }
};

TEST_F(LlvmLibcGetcTest, WriteAndReadCharactersWithFgetc) {
  test_with_func(&LIBC_NAMESPACE::fgetc, "testdata/fgetc.test");
}

TEST_F(LlvmLibcGetcTest, WriteAndReadCharactersWithGetc) {
  test_with_func(&LIBC_NAMESPACE::getc, "testdata/getc.test");
}