From 772861fc5fae1c126fcc63a8809b0a9c729bd152 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Tue, 2 Jun 2026 13:43:49 +0200
Subject: kernel/vfs: add type registry tests

---
 kernel/CMakeLists.txt                              |  1 +
 kernel/include/kernel/filesystem/type_registry.hpp |  8 ++-
 kernel/src/filesystem/type_registry.cpp            | 11 +++-
 kernel/src/filesystem/type_registry.tests.cpp      | 77 ++++++++++++++++++++++
 kernel/src/filesystem/vfs.cpp                      |  1 -
 5 files changed, 93 insertions(+), 5 deletions(-)
 create mode 100644 kernel/src/filesystem/type_registry.tests.cpp

(limited to 'kernel')

diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt
index 3dd84ba..2388370 100644
--- a/kernel/CMakeLists.txt
+++ b/kernel/CMakeLists.txt
@@ -201,6 +201,7 @@ if(BUILD_TESTING)
         "src/filesystem/mount.tests.cpp"
         "src/filesystem/open_file_descriptor.tests.cpp"
         "src/filesystem/open_file_table.tests.cpp"
+        "src/filesystem/type_registry.tests.cpp"
         "src/filesystem/vfs.tests.cpp"
         
         # Storage Subsystem Tests
diff --git a/kernel/include/kernel/filesystem/type_registry.hpp b/kernel/include/kernel/filesystem/type_registry.hpp
index 2f5e708..3be7295 100644
--- a/kernel/include/kernel/filesystem/type_registry.hpp
+++ b/kernel/include/kernel/filesystem/type_registry.hpp
@@ -7,6 +7,7 @@
 #include <kstd/memory>
 #include <kstd/string>
 
+#include <cstddef>
 #include <span>
 #include <string_view>
 
@@ -35,7 +36,12 @@ namespace kernel::filesystem
     //! Get all currently registered type descriptors.
     //!
     //! @return A span containing all currently registered filesystem type descriptors.
-    [[nodiscard]] auto all() const noexcept -> std::span<pointer>;
+    [[nodiscard]] auto all() const noexcept -> std::span<pointer const>;
+
+    //! Get the number of registered filesystem types.
+    //!
+    //! @return The number of filesystem descriptors currently registered with this registry.
+    [[nodiscard]] auto size() const noexcept -> std::size_t;
 
   private:
     //! A map from filesystem names (identifiers) to filesystem type descriptors.
diff --git a/kernel/src/filesystem/type_registry.cpp b/kernel/src/filesystem/type_registry.cpp
index 033b879..d917c81 100644
--- a/kernel/src/filesystem/type_registry.cpp
+++ b/kernel/src/filesystem/type_registry.cpp
@@ -6,6 +6,7 @@
 #include <kstd/print>
 
 #include <algorithm>
+#include <cstddef>
 #include <optional>
 #include <ranges>
 #include <span>
@@ -58,10 +59,14 @@ namespace kernel::filesystem
     return result.second;
   }
 
-  [[nodiscard]] auto type_registry::all() const noexcept -> std::span<pointer>
+  auto type_registry::all() const noexcept -> std::span<pointer const>
   {
-    // TODO: implement value accessor for flat_map
-    return {};
+    return {m_descriptors.values().begin(), m_descriptors.values().end()};
+  }
+
+  auto type_registry::size() const noexcept -> std::size_t
+  {
+    return m_descriptors.size();
   }
 
 }  // namespace kernel::filesystem
diff --git a/kernel/src/filesystem/type_registry.tests.cpp b/kernel/src/filesystem/type_registry.tests.cpp
new file mode 100644
index 0000000..8382579
--- /dev/null
+++ b/kernel/src/filesystem/type_registry.tests.cpp
@@ -0,0 +1,77 @@
+#include <kernel/filesystem/type_registry.hpp>
+
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/filesystem/type.hpp>
+
+#include <kstd/memory>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <iterator>
+#include <string_view>
+
+struct test_type final : kernel::filesystem::type
+{
+  [[nodiscard]] auto name() const noexcept -> std::string_view override
+  {
+    return "bht_testfs";
+  }
+
+  [[nodiscard]] auto requires_device() const noexcept -> bool override
+  {
+    return false;
+  }
+
+  [[nodiscard]] auto make_instance() const -> kstd::shared_ptr<kernel::filesystem::filesystem> override
+  {
+    return nullptr;
+  }
+};
+
+SCENARIO("Filesystem type registry initialization and construction", "[filesystem]")
+{
+  GIVEN("A default constructed type_registry")
+  {
+    auto instance = kernel::filesystem::type_registry{};
+
+    WHEN("getting the span of filesystem descriptors")
+    {
+      auto descriptors = instance.all();
+
+      THEN("the span is empty")
+      {
+        REQUIRE(descriptors.empty());
+      }
+    }
+  }
+}
+
+SCENARIO("Filesystem type registry modifiers", "[filesystem]")
+{
+  GIVEN("A default constructed type_registry")
+  {
+    auto instance = kernel::filesystem::type_registry{};
+
+    WHEN("adding a type descriptor")
+    {
+      auto descriptor = test_type{};
+
+      instance.add(kstd::make_observer(&descriptor));
+
+      THEN("the size of the registry is one")
+      {
+        REQUIRE(instance.size() == 1);
+      }
+
+      THEN("the span is not empty")
+      {
+        REQUIRE_FALSE(instance.all().empty());
+      }
+
+      THEN("the span's size is equal to the registry size")
+      {
+        REQUIRE(std::size(instance.all()) == std::size(instance));
+      }
+    }
+  }
+}
diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp
index 8d1fd23..e5dff8c 100644
--- a/kernel/src/filesystem/vfs.cpp
+++ b/kernel/src/filesystem/vfs.cpp
@@ -12,7 +12,6 @@
 #include <kapi/system.hpp>
 
 #include <kstd/memory>
-#include <kstd/print>
 #include <kstd/vector>
 
 #include <algorithm>
-- 
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