libc/test/src/unistd/truncate_test.cpp

   1 //===-- Unittests for truncate --------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/__support/CPP/string_view.h"
  10 #include "src/fcntl/open.h"
  11 #include "src/unistd/close.h"
  12 #include "src/unistd/read.h"
  13 #include "src/unistd/truncate.h"
  14 #include "src/unistd/unlink.h"
  15 #include "src/unistd/write.h"
  16 #include "test/ErrnoSetterMatcher.h"
  17 #include "test/UnitTest/Test.h"
  18
  19 #include <errno.h>
  20
  21 namespace cpp = __llvm_libc::cpp;
  22
  23 TEST(LlvmLibcTruncateTest, CreateAndTruncate) {
  24   using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
  25   constexpr const char TEST_FILE[] = "testdata/truncate.test";
  26   constexpr const char WRITE_DATA[] = "hello, truncate";
  27   constexpr size_t WRITE_SIZE = sizeof(WRITE_DATA);
  28   char buf[WRITE_SIZE];
  29
  30   // The test strategy is as follows:
  31   //   1. Create a normal file with some data in it.
  32   //   2. Read it to make sure what was written is actually in the file.
  33   //   3. Truncate to 1 byte.
  34   //   4. Try to read more than 1 byte and fail.
  35   errno = 0;
  36   int fd = __llvm_libc::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
  37   ASSERT_EQ(errno, 0);
  38   ASSERT_GT(fd, 0);
  39   ASSERT_EQ(ssize_t(WRITE_SIZE),
  40             __llvm_libc::write(fd, WRITE_DATA, WRITE_SIZE));
  41   ASSERT_THAT(__llvm_libc::close(fd), Succeeds(0));
  42
  43   fd = __llvm_libc::open(TEST_FILE, O_RDONLY);
  44   ASSERT_EQ(errno, 0);
  45   ASSERT_GT(fd, 0);
  46   ASSERT_EQ(ssize_t(WRITE_SIZE), __llvm_libc::read(fd, buf, WRITE_SIZE));
  47   ASSERT_EQ(cpp::string_view(buf), cpp::string_view(WRITE_DATA));
  48   ASSERT_THAT(__llvm_libc::close(fd), Succeeds(0));
  49
  50   ASSERT_THAT(__llvm_libc::truncate(TEST_FILE, off_t(1)), Succeeds(0));
  51
  52   fd = __llvm_libc::open(TEST_FILE, O_RDONLY);
  53   ASSERT_EQ(errno, 0);
  54   ASSERT_GT(fd, 0);
  55   ASSERT_EQ(ssize_t(1), __llvm_libc::read(fd, buf, WRITE_SIZE));
  56   ASSERT_EQ(buf[0], WRITE_DATA[0]);
  57   ASSERT_THAT(__llvm_libc::close(fd), Succeeds(0));
  58
  59   ASSERT_THAT(__llvm_libc::unlink(TEST_FILE), Succeeds(0));
  60 }
  61
  62 TEST(LlvmLibcTruncateTest, TruncateNonExistentFile) {
  63   using __llvm_libc::testing::ErrnoSetterMatcher::Fails;
  64   ASSERT_THAT(
  65       __llvm_libc::truncate("non-existent-dir/non-existent-file", off_t(1)),
  66       Fails(ENOENT));
  67 }