add file_descriptor_table tests

2 files changed, 160 insertions, 0 deletions

diff --git a/kernel/src/filesystem/file_descriptor_table.cpp b/kernel/src/filesystem/file_descriptor_table.cpp
index 287aea2..a31e2e6 100644
--- a/kernel/src/filesystem/file_descriptor_table.cpp
+++ b/kernel/src/filesystem/file_descriptor_table.cpp
@@ -37,6 +37,11 @@ namespace kernel::filesystem
     return *global_file_descriptor_table;
   }
 
+  auto file_descriptor_table::reset() -> void
+  {
+    global_file_descriptor_table.reset();
+  }
+
   auto file_descriptor_table::add_file(kstd::shared_ptr<open_file_description> const & file_description) -> int
   {
     if (!file_description)
diff --git a/kernel/src/filesystem/file_descriptor_table.tests.cpp b/kernel/src/filesystem/file_descriptor_table.tests.cpp
new file mode 100644
index 0000000..c431d01
--- /dev/null
+++ b/kernel/src/filesystem/file_descriptor_table.tests.cpp
@@ -0,0 +1,155 @@
+#include "kernel/filesystem/file_descriptor_table.hpp"
+
+#include "kernel/filesystem/open_file_description.hpp"
+#include "kernel/test_support/cpu.hpp"
+#include "kernel/test_support/filesystem/inode.hpp"
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+struct file_descriptor_table_RAII
+{
+  file_descriptor_table_RAII()
+  {
+    kernel::filesystem::file_descriptor_table::init();
+  }
+  ~file_descriptor_table_RAII()
+  {
+    kernel::filesystem::file_descriptor_table::reset();
+  }
+};
+
+struct file_descriptor_table_reset_only
+{
+  ~file_descriptor_table_reset_only()
+  {
+    kernel::filesystem::file_descriptor_table::reset();
+  }
+};
+
+SCENARIO_METHOD(file_descriptor_table_reset_only, "File descriptor table initialization",
+                "[filesystem][file_descriptor_table]")
+{
+  THEN("accessing the file descriptor table before initialization panics")
+  {
+    REQUIRE_THROWS_AS(kernel::filesystem::file_descriptor_table::get(), kernel::tests::cpu::halt);
+  }
+
+  THEN("the file descriptor table can be initialized and accessed")
+  {
+    kernel::filesystem::file_descriptor_table::init();
+    REQUIRE_NOTHROW(kernel::filesystem::file_descriptor_table::get());
+  }
+
+  THEN("initializing the file descriptor table more than once panics")
+  {
+    kernel::filesystem::file_descriptor_table::init();
+    REQUIRE_THROWS_AS(kernel::filesystem::file_descriptor_table::init(), kernel::tests::cpu::halt);
+  }
+}
+
+SCENARIO_METHOD(file_descriptor_table_RAII, "File descriptor table add/get file", "[filesystem][file_descriptor_table]")
+{
+  GIVEN("a file descriptor table and an open file description")
+  {
+    auto & table = kernel::filesystem::file_descriptor_table::get();
+    auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+    auto file_description_1 = kstd::make_shared<kernel::filesystem::open_file_description>(inode);
+    auto file_description_2 = kstd::make_shared<kernel::filesystem::open_file_description>(inode);
+
+    WHEN("adding the open file description to the file descriptor table")
+    {
+      auto fd_1 = table.add_file(file_description_1);
+      auto fd_2 = table.add_file(file_description_2);
+      auto fd_3 = table.add_file(file_description_2);
+
+      THEN("a valid file descriptor is returned")
+      {
+        REQUIRE(fd_1 == 0);
+        REQUIRE(fd_2 == 1);
+        REQUIRE(fd_3 == 1);
+      }
+
+      THEN("the file description can be retrieved using the returned file descriptor")
+      {
+        auto retrieved_description = table.get_file(fd_1);
+        REQUIRE(retrieved_description == file_description_1);
+      }
+    }
+  }
+
+  GIVEN("a invalid open file description")
+  {
+    auto & table = kernel::filesystem::file_descriptor_table::get();
+
+    THEN("adding a null file description returns an error code")
+    {
+      auto fd = table.add_file(nullptr);
+      REQUIRE(fd == -1);
+    }
+
+    THEN("retrieving a file description with a negative file descriptor returns a null pointer")
+    {
+      auto retrieved_description = table.get_file(-1);
+      REQUIRE(retrieved_description == nullptr);
+    }
+
+    THEN("retrieving a file description with an out-of-bounds file descriptor returns a null pointer")
+    {
+      auto retrieved_description = table.get_file(1000);
+      REQUIRE(retrieved_description == nullptr);
+    }
+  }
+}
+
+SCENARIO_METHOD(file_descriptor_table_RAII, "File descriptor table remove file", "[filesystem][file_descriptor_table]")
+{
+  GIVEN("a file descriptor table with an open file description")
+  {
+    auto & table = kernel::filesystem::file_descriptor_table::get();
+    auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+    auto file_description = kstd::make_shared<kernel::filesystem::open_file_description>(inode);
+    auto fd = table.add_file(file_description);
+
+    WHEN("removing the file description using the file descriptor")
+    {
+      table.remove_file(fd);
+
+      THEN("the file description can no longer be retrieved using the file descriptor")
+      {
+        auto retrieved_description = table.get_file(fd);
+        REQUIRE(retrieved_description == nullptr);
+      }
+    }
+
+    WHEN("removing a file description the other file descriptor keep the same index")
+    {
+      auto fd2 = table.add_file(file_description);
+      table.remove_file(fd);
+
+      THEN("the second file description can still be retrieved using its file descriptor")
+      {
+        auto retrieved_description = table.get_file(fd2);
+        REQUIRE(retrieved_description == file_description);
+      }
+    }
+  }
+
+  GIVEN("an invalid file descriptor")
+  {
+    auto & table = kernel::filesystem::file_descriptor_table::get();
+
+    THEN("removing a file with a negative file descriptor does nothing")
+    {
+      REQUIRE_NOTHROW(table.remove_file(-1));
+    }
+
+    THEN("removing a file with an out-of-bounds file descriptor does nothing")
+    {
+      REQUIRE_NOTHROW(table.remove_file(1000));
+    }
+  }
+}
\ No newline at end of file