Tests/Kernel: Add test cases for proper types in dirent for various FSes

Tests/Kernel/CMakeLists.txt

@@ -41,6 +41,7 @@ set(LIBTEST_BASED_SOURCES
     TestEmptyPrivateInodeVMObject.cpp
     TestEmptySharedInodeVMObject.cpp
     TestExt2FS.cpp
+    TestFileSystemDirentTypes.cpp
     TestInvalidUIDSet.cpp
     TestSharedInodeVMObject.cpp
     TestPosixFallocate.cpp

Tests/Kernel/TestFileSystemDirentTypes.cpp

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2024, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/API/POSIX/dirent.h>
+#include <LibTest/TestCase.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+TEST_CASE(test_sysfs_root_directory)
+{
+    auto dirfd = open("/sys/", O_RDONLY | O_DIRECTORY);
+    auto cleanup_guard = ScopeGuard([&] {
+        close(dirfd);
+    });
+
+    DIR* dir = fdopendir(dirfd);
+    EXPECT(dir != nullptr);
+
+    auto cleanup_dir_guard = ScopeGuard([&] {
+        closedir(dir);
+    });
+
+    auto* _dirent = readdir(dir);
+    EXPECT(_dirent != nullptr);
+    // NOTE: We should see '.'
+    EXPECT_EQ(_dirent->d_type, DT_DIR);
+
+    _dirent = readdir(dir);
+    EXPECT(_dirent != nullptr);
+    // NOTE: We should see '..'
+    EXPECT_EQ(_dirent->d_type, DT_DIR);
+
+    while (true) {
+        _dirent = readdir(dir);
+        if (_dirent == nullptr)
+            break;
+        // NOTE: We should only see a directory entry in the /sys directory
+        EXPECT_EQ(_dirent->d_type, DT_DIR);
+    }
+}
+
+TEST_CASE(test_devpts_root_directory)
+{
+    auto dirfd = open("/dev/pts/", O_RDONLY | O_DIRECTORY);
+    auto cleanup_guard = ScopeGuard([&] {
+        close(dirfd);
+    });
+
+    DIR* dir = fdopendir(dirfd);
+    EXPECT(dir != nullptr);
+
+    auto cleanup_dir_guard = ScopeGuard([&] {
+        closedir(dir);
+    });
+
+    auto* _dirent = readdir(dir);
+    EXPECT(_dirent != nullptr);
+    // NOTE: We should see '.'
+    EXPECT_EQ(_dirent->d_type, DT_DIR);
+
+    _dirent = readdir(dir);
+    EXPECT(_dirent != nullptr);
+    // NOTE: We should see '..'
+    EXPECT_EQ(_dirent->d_type, DT_DIR);
+}
+
+TEST_CASE(test_procfs_root_directory)
+{
+    auto dirfd = open("/proc/", O_RDONLY | O_DIRECTORY);
+    auto cleanup_guard = ScopeGuard([&] {
+        close(dirfd);
+    });
+
+    DIR* dir = fdopendir(dirfd);
+    EXPECT(dir != nullptr);
+
+    auto cleanup_dir_guard = ScopeGuard([&] {
+        closedir(dir);
+    });
+
+    auto* _dirent = readdir(dir);
+    EXPECT(_dirent != nullptr);
+    // NOTE: We should see '.' now
+    EXPECT_EQ(_dirent->d_type, DT_DIR);
+
+    _dirent = readdir(dir);
+    EXPECT(_dirent != nullptr);
+    // NOTE: We should see '..' now
+    EXPECT_EQ(_dirent->d_type, DT_DIR);
+
+    _dirent = readdir(dir);
+    EXPECT(_dirent != nullptr);
+    // NOTE: We should see 'self' now
+    EXPECT_EQ(_dirent->d_type, DT_LNK);
+}