2 files changed, 45 insertions, 1 deletions
diff --git a/kernel/kapi/filesystem.tests.cpp b/kernel/kapi/filesystem.tests.cpp
index d1e01db6..2c2a8d1e 100644
--- a/kernel/kapi/filesystem.tests.cpp
+++ b/kernel/kapi/filesystem.tests.cpp
@@ -39,6 +39,30 @@ SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_vfs_fixture, "Kap
       REQUIRE(kapi::filesystem::close(fd));
     }
 
+    THEN("files can be opened, written to, read from and closed again")
+    {
+      auto write_fd = kapi::filesystem::open("/information/info_1.txt");
+      REQUIRE(write_fd >= 0);
+
+      auto write_buffer = std::vector<std::byte>{std::byte{'H'}, std::byte{'e'}};
+
+      auto const bytes_written = kapi::filesystem::write(write_fd, write_buffer.data(), write_buffer.size());
+      REQUIRE(bytes_written == 2);
+
+      auto read_fd = kapi::filesystem::open("/information/info_1.txt");
+      REQUIRE(read_fd >= 0);
+
+      auto read_buffer = std::vector<std::byte>(6);
+      auto const bytes_read = kapi::filesystem::read(read_fd, read_buffer.data(), read_buffer.size());
+      REQUIRE(bytes_read >= 0);
+
+      std::string_view buffer_as_str{reinterpret_cast<char *>(read_buffer.data()), static_cast<size_t>(bytes_read)};
+      REQUIRE(buffer_as_str == "Hefo_1");
+
+      REQUIRE(kapi::filesystem::close(write_fd) == 0);
+      REQUIRE(kapi::filesystem::close(read_fd) == 0);
+    }
+
     THEN("files can be opened through absolute symbolic link, read and closed again")
     {
       auto fd = kapi::filesystem::open("/symlinks/information_directory_absolute/info_1.txt").value();
diff --git a/kernel/kernel/filesystem/open_file_descriptor.tests.cpp b/kernel/kernel/filesystem/open_file_descriptor.tests.cpp
index 06488ba0..daf9327f 100644
--- a/kernel/kernel/filesystem/open_file_descriptor.tests.cpp
+++ b/kernel/kernel/filesystem/open_file_descriptor.tests.cpp
@@ -95,7 +95,7 @@ SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_vfs_fixture, "Ope
       REQUIRE(buffer_as_str == "info_1\n");
     }
 
-    THEN("the file can be read multiple times")
+    THEN("the file can be read multiple times and the offset is updated")
     {
       kstd::vector<std::byte> buffer(4);
       auto bytes_read_1 = ofd->read(buffer.data(), buffer.size() / 2);
@@ -109,5 +109,25 @@ SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_vfs_fixture, "Ope
       std::string_view buffer_as_str{reinterpret_cast<char *>(buffer.data()), *bytes_read_1 + *bytes_read_2};
       REQUIRE(buffer_as_str == "info");
     }
+
+    THEN("the file can be written to and the offset is updated")
+    {
+      auto write_buffer = kstd::vector<std::byte>(12, std::byte{0xAA});
+      auto const bytes_written = ofd->write(write_buffer.data(), write_buffer.size());
+      REQUIRE(bytes_written == 7);
+      REQUIRE(ofd->offset() == 7);
+    }
+
+    THEN("the file can be written to multiple times and the offset is updated")
+    {
+      auto write_buffer = kstd::vector<std::byte>(8, std::byte{0xAA});
+      auto const bytes_written_1 = ofd->write(write_buffer.data(), write_buffer.size() / 2);
+      REQUIRE(bytes_written_1 == write_buffer.size() / 2);
+      REQUIRE(ofd->offset() == write_buffer.size() / 2);
+
+      auto const bytes_written_2 = ofd->write(write_buffer.data() + write_buffer.size() / 2, write_buffer.size() / 2);
+      REQUIRE(bytes_written_2 == 3);
+      REQUIRE(ofd->offset() == 7);
+    }
   }
 }