From eacc1becd1308a01a7ffcddf7c8910c8dc708939 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Tue, 14 Apr 2026 13:52:19 +0200
Subject: acpi: begin test implementation

---
 .clangd                                |  1 +
 .devcontainer/x86-64/devcontainer.json |  2 +-
 libs/acpi/CMakeLists.txt               | 19 +++++++++++++++++++
 libs/acpi/acpi/pointers.cpp            |  4 ++--
 libs/acpi/acpi/pointers.test.cpp       | 29 +++++++++++++++++++++++++++++
 5 files changed, 52 insertions(+), 3 deletions(-)
 create mode 100644 libs/acpi/acpi/pointers.test.cpp

diff --git a/.clangd b/.clangd
index fac5c82..ce14df5 100644
--- a/.clangd
+++ b/.clangd
@@ -11,6 +11,7 @@ Documentation:
 If:
   PathMatch:
     - "libs/.*/tests/.*\\.cpp"
+    - "libs/.*/.*\\.test\\.cpp"
     - "kernel/.*\\.tests.cpp"
 Diagnostics:
   ClangTidy:
diff --git a/.devcontainer/x86-64/devcontainer.json b/.devcontainer/x86-64/devcontainer.json
index 6bf1616..775da72 100644
--- a/.devcontainer/x86-64/devcontainer.json
+++ b/.devcontainer/x86-64/devcontainer.json
@@ -5,7 +5,7 @@
     "ghcr.io/devcontainers/features/git:1": {},
     "ghcr.io/devcontainers/features/git-lfs:1": {},
     "ghcr.io/devcontainers-extra/features/apt-packages:1": {
-      "packages": "build-essential,clang-tidy,clangd,cmake,grub2-common,grub-pc,mtools,ninja-build,qemu-system-x86,ssh,xorriso,gdb"
+      "packages": "acpica-tools,build-essential,clang-tidy,clangd,cmake,grub2-common,grub-pc,mtools,ninja-build,qemu-system-x86,ssh,xorriso,gdb"
     }
   },
   "customizations": {
diff --git a/libs/acpi/CMakeLists.txt b/libs/acpi/CMakeLists.txt
index c6e63b9..b8face4 100644
--- a/libs/acpi/CMakeLists.txt
+++ b/libs/acpi/CMakeLists.txt
@@ -27,3 +27,22 @@ target_sources("acpi" PUBLIC
 target_link_libraries("acpi" PUBLIC
   "libs::kstd"
 )
+
+if(NOT CMAKE_CROSSCOMPILING)
+  add_executable("acpi_tests"
+    "acpi/pointers.test.cpp"
+  )
+
+  target_link_libraries("acpi_tests" PRIVATE
+    "Catch2::Catch2WithMain"
+    "libs::acpi"
+  )
+
+  set_target_properties("acpi_tests" PROPERTIES
+    C_CLANG_TIDY ""
+    CXX_CLANG_TIDY ""
+    EXCLUDE_FROM_ALL NO
+  )
+
+  catch_discover_tests("acpi_tests")
+endif()
diff --git a/libs/acpi/acpi/pointers.cpp b/libs/acpi/acpi/pointers.cpp
index b206cc6..8a8629f 100644
--- a/libs/acpi/acpi/pointers.cpp
+++ b/libs/acpi/acpi/pointers.cpp
@@ -34,7 +34,7 @@ namespace acpi
 
   auto rsdp::validate() const noexcept -> bool
   {
-    return validate_checksum({reinterpret_cast<std::byte const *>(this), sizeof(rsdp)});
+    return signature() == "RSD PTR " && validate_checksum({reinterpret_cast<std::byte const *>(this), sizeof(rsdp)});
   }
 
   auto xsdp::length() const noexcept -> kstd::units::bytes
@@ -49,7 +49,7 @@ namespace acpi
 
   auto xsdp::validate() const noexcept -> bool
   {
-    return validate_checksum({reinterpret_cast<std::byte const *>(this), m_length});
+    return signature() == "RSD PTR " && validate_checksum({reinterpret_cast<std::byte const *>(this), m_length});
   }
 
 }  // namespace acpi
diff --git a/libs/acpi/acpi/pointers.test.cpp b/libs/acpi/acpi/pointers.test.cpp
new file mode 100644
index 0000000..06ce1a4
--- /dev/null
+++ b/libs/acpi/acpi/pointers.test.cpp
@@ -0,0 +1,29 @@
+#include <acpi/pointers.hpp>
+#include <catch2/catch_test_macros.hpp>
+
+#include <array>
+#include <bit>
+#include <cstddef>
+
+SCENARIO("ACPI root pointer parsing", "[acpi]")
+{
+  GIVEN("A null-filled pointer")
+  {
+    auto data = std::array<std::byte, sizeof(acpi::rsdp)>{};
+
+    WHEN("parsing the data")
+    {
+      auto rsdp = std::bit_cast<acpi::rsdp>(data);
+
+      THEN("the signature is invalid")
+      {
+        REQUIRE(rsdp.signature() != "RSD PTR ");
+      }
+
+      THEN("validate returns false")
+      {
+        REQUIRE_FALSE(rsdp.validate());
+      }
+    }
+  }
+}
-- 
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