4 files changed, 166 insertions, 0 deletions
diff --git a/kernel/src/test_support/kapi/cio.cpp b/kernel/src/test_support/kapi/cio.cpp
new file mode 100644
index 0000000..35452d4
--- /dev/null
+++ b/kernel/src/test_support/kapi/cio.cpp
@@ -0,0 +1,43 @@
+#include <kapi/cio.hpp>
+
+#include "kernel/test_support/log_buffer.hpp"
+
+#include <iostream>
+#include <string>
+#include <string_view>
+
+namespace kapi::cio
+{
+
+  namespace
+  {
+
+    class test_output_device : public output_device
+    {
+    public:
+      test_output_device() = default;
+
+      auto write(output_stream stream, std::string_view text) -> void override
+      {
+        auto & standard_stream = stream == output_stream::stdout ? std::cout : std::cerr;
+        standard_stream << text;
+        if (text != "\n")
+        {
+          kernel::tests::log_buffer::append(std::string{text});
+        }
+      }
+    } device{};
+
+  }  // namespace
+
+  auto init() -> void
+  {
+    set_output_device(device);
+  }
+
+  auto reset() -> void
+  {
+    kernel::tests::log_buffer::clear();
+  }
+
+}  // namespace kapi::cio
+\ No newline at end of file
diff --git a/kernel/src/test_support/kapi/cpu.cpp b/kernel/src/test_support/kapi/cpu.cpp
new file mode 100644
index 0000000..6592d15
--- /dev/null
+++ b/kernel/src/test_support/kapi/cpu.cpp
@@ -0,0 +1,41 @@
+#include "kernel/test_support/cpu.hpp"
+
+#include <kapi/cpu.hpp>
+
+#include <atomic>
+#include <stdexcept>
+
+namespace kapi::cpu
+{
+
+  namespace
+  {
+    auto static initialized = std::atomic_flag{};
+  }
+
+  auto reset() -> void
+  {
+    if (!initialized.test())
+    {
+      throw std::logic_error{"kapi::cpu::reset() called before kapi::cpu::init()"};
+    }
+
+    initialized.clear();
+  }
+
+  auto init() -> void
+  {
+    if (initialized.test_and_set())
+    {
+      throw std::logic_error("kapi::cpu::init() called more than once");
+    }
+
+    // TODO: make sure that simulated interrupt can run.
+  }
+
+  auto halt() -> void
+  {
+    throw kernel::tests::cpu::halt{};
+  }
+
+}  // namespace kapi::cpu
+\ No newline at end of file
diff --git a/kernel/src/test_support/kapi/interrupts.cpp b/kernel/src/test_support/kapi/interrupts.cpp
new file mode 100644
index 0000000..0077266
--- /dev/null
+++ b/kernel/src/test_support/kapi/interrupts.cpp
@@ -0,0 +1,11 @@
+#include <kapi/interrupts.hpp>
+
+namespace kapi::interrupts
+{
+
+  auto enable() -> void
+  {
+    // TODO: enable simulated interrupts.
+  }
+
+}  // namespace kapi::interrupts
+\ No newline at end of file
diff --git a/kernel/src/test_support/kapi/memory.cpp b/kernel/src/test_support/kapi/memory.cpp
new file mode 100644
index 0000000..f244b7f
--- /dev/null
+++ b/kernel/src/test_support/kapi/memory.cpp
@@ -0,0 +1,71 @@
+#include "kapi/memory.hpp"
+
+#include <kapi/memory.hpp>
+
+#include "kernel/test_support/bump_frame_allocator.hpp"
+#include "kernel/test_support/page_mapper.hpp"
+
+#include <kstd/units>
+
+#include <optional>
+
+namespace
+{
+  //! The size of the simulated RAM.
+  constexpr auto memory_size = kstd::units::MiB(32);
+  constexpr auto number_of_frames = memory_size / kapi::memory::frame::size;
+
+  auto constinit bump_allocator = std::optional<kernel::tests::bump_frame_allocator>{};
+  auto constinit test_mapper = std::optional<kernel::tests::page_mapper>{};
+
+  auto constinit old_allocator = std::optional<kapi::memory::frame_allocator *>{};
+  auto constinit old_mapper = std::optional<kapi::memory::page_mapper *>{};
+
+  auto handoff_to_kernel_pmm(kapi::memory::frame_allocator & new_allocator) -> void
+  {
+    auto first_free_frame = bump_allocator->next_free_frame;
+    auto number_of_free_frames = number_of_frames - first_free_frame;
+    new_allocator.release_many({kapi::memory::frame{first_free_frame}, number_of_free_frames});
+  }
+
+}  // namespace
+
+namespace kapi::memory
+{
+
+  auto init() -> void
+  {
+    bump_allocator.emplace();
+    test_mapper.emplace(memory_size);
+
+    old_allocator = set_frame_allocator(*bump_allocator);
+    old_mapper = set_page_mapper(*test_mapper);
+
+    init_pmm(memory_size / frame::size, handoff_to_kernel_pmm);
+  }
+
+  auto reset() -> void
+  {
+    if (old_allocator && *old_allocator)
+    {
+      set_frame_allocator(**old_allocator);
+    }
+
+    if (old_mapper && *old_mapper)
+    {
+      set_page_mapper(**old_mapper);
+    }
+
+    bump_allocator.reset();
+    test_mapper.reset();
+  }
+
+}  // namespace kapi::memory
+
+namespace kernel::tests::memory
+{
+  auto heap_base() -> kapi::memory::linear_address
+  {
+    return test_mapper->memory.heap_base();
+  }
+}  // namespace kernel::tests::memory
+\ No newline at end of file