Tests: Add a generic test for reported file sizes

Tests/Kernel/CMakeLists.txt

@@ -43,6 +43,7 @@ set(LIBTEST_BASED_SOURCES
  TestEmptySharedInodeVMObject.cpp
  TestExt2FS.cpp
  TestFileSystemDirentTypes.cpp
+ TestFileSystemReportedSize.cpp
  TestInvalidUIDSet.cpp
  TestSharedInodeVMObject.cpp
  TestPosixFallocate.cpp

Tests/Kernel/TestFileSystemReportedSize.cpp

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2024, sdomi <[email protected]>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibTest/TestCase.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+static void test_write_path(const char* path)
+{
+ struct stat st;
+
+ auto fd = open(path, O_RDWR | O_CREAT);
+ EXPECT_NE(fd, -1);
+
+ EXPECT_NE(fstat(fd, &st), -1);
+ EXPECT(st.st_blocks == 0);
+ EXPECT_EQ(st.st_size, 0);
+
+ auto rc = write(fd, "meow", 4);
+ EXPECT_NE(rc, 0);
+
+ EXPECT_NE(fstat(fd, &st), -1);
+
+ EXPECT(st.st_blocks > 0);
+ EXPECT(st.st_size > 0);
+ close(fd);
+ unlink(path);
+}
+
+TEST_CASE(reported_blocksize_ramfs)
+{
+ test_write_path("/tmp/asdf");
+}
+
+TEST_CASE(reported_blocksize_ext2fs)
+{
+ test_write_path("/home/anon/asdf");
+}
+
+// TODO: automate testing of FatFS/FUSE/...