diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
index 502ec61..c4c644b 100644
--- a/.gitea/workflows/ci.yml
+++ b/.gitea/workflows/ci.yml
@@ -99,6 +99,8 @@ jobs:
         run: python3 modulus.py configure --target x86_64_gcc12_release
       - name: Build native release
         run: python3 modulus.py build --target x86_64_gcc12_release
+      - name: Test native release
+        run: python3 modulus.py test --target x86_64_gcc12_release
       - name: Fetch Pico SDK
         if: ${{ gitea.event_name == 'workflow_dispatch' || (gitea.event_name == 'push' && gitea.ref == 'refs/heads/master') }}
         env:
diff --git a/TECHNICAL_GUIDE.md b/TECHNICAL_GUIDE.md
index 3ac70ed..16f3f44 100644
--- a/TECHNICAL_GUIDE.md
+++ b/TECHNICAL_GUIDE.md
@@ -30,8 +30,8 @@ The AP setup pins NetworkManager to 2.4 GHz channel 6 with WPA2/RSN and CCMP cip
 
 On Raspberry Pi OS Lite, the installed display service owns `tty1`, conflicts with `getty@tty1.service`, and starts the Zero container through `product-vamp-start-zero`. The wrapper switches to the display VT when `chvt` is available and runs `vamp-zero` inside the container through `setsid --wait --ctty` with `/dev/tty1` as stdin, giving raylib's DRM backend a real virtual terminal while keeping Docker attached to the long-running display process. SSH remains the normal admin path and `tty2` is enabled as the fallback local console.
 
-At startup the Zero scans `share/product-vamp/songs/*.json` and `share/product-vamp/practice/<type>/<lesson_group>/<exercise>/<key>.json`, parses generated score JSON, imports both catalogs into SQLite with Noto, then reloads runtime menu state from the database. Runtime navigation and rendering use that loaded Noto-backed state instead of rescanning asset folders. The UI supports a top-level mode menu, Performance song/part/score menus, and Practice type/lesson/exercise/key/score menus. Melody practice offers key selection by choosing a pre-generated score variant; chord practice skips key selection and renders the authored score key directly. The score renderer is intentionally local and compact for now: it draws title/composer/part metadata, systems, measures, enlarged chord symbols and section labels, Petaluma SMuFL noteheads/rests/flags/dots/accidentals, simple vector stems/ties, and lyrics. Slash notation is represented explicitly with `notehead: "slash"` in generated JSON.
-Petaluma music symbols are placed from SMuFL bounding boxes and stem/flag anchors instead of rough font-size offsets, which keeps noteheads, rests, dots, accidentals, and eighth-note flags aligned to staff-space coordinates.
+At startup the Zero scans `share/product-vamp/songs/*.json` and `share/product-vamp/practice/<type>/<lesson_group>/<exercise>/<key>.json`, parses generated score JSON, imports both catalogs into SQLite with Noto, then reloads runtime menu state from the database. Runtime navigation and rendering use that loaded Noto-backed state instead of rescanning asset folders. The UI supports a top-level mode menu, Performance song/part/score menus, and Practice type/lesson/exercise/key/score menus. Melody practice offers key selection by choosing a pre-generated score variant; chord practice skips key selection and renders the authored score key directly. The score renderer draws title/composer/part metadata, systems, measures, clef/key/time preambles, enlarged chord symbols and section labels, Petaluma SMuFL noteheads/rests/flags/dots/accidentals, simple vector stems/ties, and lyrics. Slash notation is represented explicitly with `notehead: "slash"` in generated JSON.
+Petaluma music symbols are placed from SMuFL bounding boxes and stem/flag anchors instead of rough font-size offsets, which keeps clefs, noteheads, rests, dots, accidentals, and eighth-note flags aligned to staff-space coordinates. Printed accidentals are derived from the active key signature and per-measure accidental state, so natural signs are shown only when they are musically required.
 
 ## Score Generation
 
diff --git a/cmake/vamp_options.cmake b/cmake/vamp_options.cmake
index 78eb585..d54c722 100644
--- a/cmake/vamp_options.cmake
+++ b/cmake/vamp_options.cmake
@@ -1,7 +1,7 @@
 option(VAMP_PICO_FIRMWARE_PROJECT "Configure this CMake invocation as the Pi Pico 2 W firmware project" OFF)
 option(VAMP_BUILD_PICO_FIRMWARE "Build the Pi Pico 2 W UF2 firmware artifact" OFF)
 option(VAMP_BUILD_ZERO_IMAGE "Build the Pi Zero 2 W Docker image archive artifact" OFF)
-option(BUILD_TESTING "Compatibility option accepted by Modulus; Product Vamp does not currently define tests" OFF)
+option(BUILD_TESTING "Build Product Vamp tests" OFF)
 
 set(VAMP_PICO_SDK_VERSION "2.3.0" CACHE STRING "Raspberry Pi Pico SDK git tag used when fetching the SDK")
 set(VAMP_PICO_WIFI_SSID "Vamp Control" CACHE STRING "Default Pico Wi-Fi SSID")
diff --git a/cmake/zero.cmake b/cmake/zero.cmake
index 797742d..ffa0d61 100644
--- a/cmake/zero.cmake
+++ b/cmake/zero.cmake
@@ -1,4 +1,5 @@
 include(GNUInstallDirs)
+include(CTest)
 
 set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
@@ -82,6 +83,10 @@ add_executable(vamp-zero src/vamp_zero/main.cpp)
 target_compile_features(vamp-zero PRIVATE cxx_std_23)
 target_link_libraries(vamp-zero PRIVATE vamp-zero-core)
 
+if(BUILD_TESTING)
+  add_subdirectory(tests)
+endif()
+
 set(VAMP_BUNDLE_DIR ${CMAKE_CURRENT_BINARY_DIR}/bundle)
 set(VAMP_MANIFEST ${VAMP_BUNDLE_DIR}/manifest.json)
 configure_file(package/manifest.json.in ${VAMP_MANIFEST} @ONLY)
diff --git a/conanfile.py b/conanfile.py
index 232f8dd..4607899 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -1,4 +1,5 @@
 import conan
+import conan.tools.build
 import conan.tools.cmake
 
 class product_vamp_conan(conan.ConanFile):
@@ -47,6 +48,9 @@ class product_vamp_conan(conan.ConanFile):
     "src/vamp_pico/*.cpp",
     "src/vamp_protocol/*.cpp",
     "src/vamp_zero/*.cpp",
+    "tests/CMakeLists.txt",
+    "tests/*.cpp",
+    "tests/*.hpp",
   )
 
   def requirements(self):
@@ -72,12 +76,15 @@ class product_vamp_conan(conan.ConanFile):
     toolchain = conan.tools.cmake.CMakeToolchain(self)
     if hasattr(toolchain, "user_presets_path"):
       toolchain.user_presets_path = False
+    toolchain.variables["BUILD_TESTING"] = bool(self.options.with_tests)
     toolchain.generate()
 
   def build(self):
     cmake = conan.tools.cmake.CMake(self)
     cmake.configure()
     cmake.build()
+    if self.options.with_tests and conan.tools.build.can_run(self):
+      cmake.test(target="check")
 
   def package_id(self):
     self.info.options.rm_safe("with_tests")
diff --git a/include/vamp_zero/score.hpp b/include/vamp_zero/score.hpp
index 814ab16..ac85e99 100644
--- a/include/vamp_zero/score.hpp
+++ b/include/vamp_zero/score.hpp
@@ -1,6 +1,8 @@
 #pragma once
 
 #include <cstddef>
+#include <string_view>
+#include <vector>
 
 #include <luma.hpp>
 
@@ -8,10 +10,18 @@
 
 namespace vamp_zero {
 
+enum class score_accidental_mark {
+  NONE,
+  FLAT,
+  NATURAL,
+  SHARP,
+};
+
 constexpr auto score_measures_per_system = std::size_t{4};
 constexpr auto score_systems_per_page = std::size_t{3};
 constexpr auto score_measures_per_page = score_measures_per_system * score_systems_per_page;
 
+auto notated_accidentals_for_measure(vamp_zero::score_measure const& measure, std::string_view inherited_key_signature) -> std::vector<vamp_zero::score_accidental_mark>;
 auto draw_score_page(luma::draw_context& context, luma::rect bounds, vamp_zero::score_document const& score, std::size_t page_index) -> void;
 
 }
diff --git a/include/vamp_zero/types.hpp b/include/vamp_zero/types.hpp
index 7c674b9..da55abb 100644
--- a/include/vamp_zero/types.hpp
+++ b/include/vamp_zero/types.hpp
@@ -48,6 +48,8 @@ struct score_document {
   std::string title{};
   std::string composer{};
   std::string key_signature{};
+  std::string time_signature{};
+  std::string clef{};
   std::string part{};
   std::string arrangement_part_type{};
   std::string source_path{};
diff --git a/src/vamp_zero/library.cpp b/src/vamp_zero/library.cpp
index a2c99f9..3f528cf 100644
--- a/src/vamp_zero/library.cpp
+++ b/src/vamp_zero/library.cpp
@@ -359,8 +359,9 @@ auto vamp_zero::parse_score_document(std::string_view json, std::string source_p
   auto title = required_string(**metadata, "title");
   auto composer = optional_string_value(**metadata, "composer", {});
   auto key = optional_string_value(**metadata, "key_signature", {});
-  if (!title || !composer || !key) {
-    return std::unexpected(!title ? title.error() : (!composer ? composer.error() : key.error()));
+  auto time = optional_string_value(**metadata, "time_signature", {});
+  if (!title || !composer || !key || !time) {
+    return std::unexpected(!title ? title.error() : (!composer ? composer.error() : (!key ? key.error() : time.error())));
   }
 
   auto staves = require_array(**root, "staves");
@@ -381,6 +382,10 @@ auto vamp_zero::parse_score_document(std::string_view json, std::string source_p
   if (!part) {
     return std::unexpected(part.error());
   }
+  auto clef = optional_string_value(staff, "clef", "treble");
+  if (!clef) {
+    return std::unexpected(clef.error());
+  }
 
   auto measures = require_array(staff, "measures");
   if (!measures) {
@@ -391,6 +396,8 @@ auto vamp_zero::parse_score_document(std::string_view json, std::string source_p
     .title = std::move(*title),
     .composer = std::move(*composer),
     .key_signature = std::move(*key),
+    .time_signature = std::move(*time),
+    .clef = clef->empty() ? std::string{"treble"} : std::move(*clef),
     .part = human_label(*part),
     .arrangement_part_type = std::move(*part),
     .source_path = std::move(source_path),
@@ -401,8 +408,20 @@ auto vamp_zero::parse_score_document(std::string_view json, std::string source_p
     if (!measure) {
       return std::unexpected(measure.error());
     }
+    if (document.key_signature.empty() && !measure->key_signature.empty()) {
+      document.key_signature = measure->key_signature;
+    }
+    if (document.time_signature.empty() && !measure->time_signature.empty()) {
+      document.time_signature = measure->time_signature;
+    }
     document.measures.push_back(std::move(*measure));
   }
+  if (document.key_signature.empty()) {
+    document.key_signature = "C";
+  }
+  if (document.time_signature.empty()) {
+    document.time_signature = "4/4";
+  }
   return document;
 }
 
diff --git a/src/vamp_zero/score.cpp b/src/vamp_zero/score.cpp
index 69cb22c..88badcd 100644
--- a/src/vamp_zero/score.cpp
+++ b/src/vamp_zero/score.cpp
@@ -1,13 +1,16 @@
 #include <vamp_zero/score.hpp>
 
 #include <algorithm>
+#include <array>
 #include <cmath>
 #include <cstddef>
 #include <cstdint>
+#include <map>
 #include <optional>
 #include <string>
 #include <string_view>
 #include <unordered_map>
+#include <utility>
 #include <vector>
 
 #include <raylib.h>
@@ -52,6 +55,13 @@ struct notehead_instance {
   luma::point origin{};
 };
 
+struct key_signature_position {
+  std::char_t letter{};
+  std::int32_t octave{};
+};
+
+constexpr auto glyph_g_clef = std::int32_t{0xe050};
+constexpr auto glyph_f_clef = std::int32_t{0xe062};
 constexpr auto glyph_notehead_whole = std::int32_t{0xe0a2};
 constexpr auto glyph_notehead_half = std::int32_t{0xe0a3};
 constexpr auto glyph_notehead_black = std::int32_t{0xe0a4};
@@ -66,6 +76,7 @@ constexpr auto glyph_augmentation_dot = std::int32_t{0xe1e7};
 constexpr auto glyph_accidental_flat = std::int32_t{0xe260};
 constexpr auto glyph_accidental_natural = std::int32_t{0xe261};
 constexpr auto glyph_accidental_sharp = std::int32_t{0xe262};
+constexpr auto glyph_time_sig_0 = std::int32_t{0xe080};
 
 auto to_raylib(luma::color color) -> Color {
   return {
@@ -104,6 +115,8 @@ auto music_font(std::float32_t size) -> Font {
   }
 
   auto codepoints = std::vector<std::int32_t>{
+    glyph_g_clef,
+    glyph_f_clef,
     glyph_notehead_whole,
     glyph_notehead_half,
     glyph_notehead_black,
@@ -118,6 +131,16 @@ auto music_font(std::float32_t size) -> Font {
     glyph_accidental_flat,
     glyph_accidental_natural,
     glyph_accidental_sharp,
+    glyph_time_sig_0,
+    glyph_time_sig_0 + 1,
+    glyph_time_sig_0 + 2,
+    glyph_time_sig_0 + 3,
+    glyph_time_sig_0 + 4,
+    glyph_time_sig_0 + 5,
+    glyph_time_sig_0 + 6,
+    glyph_time_sig_0 + 7,
+    glyph_time_sig_0 + 8,
+    glyph_time_sig_0 + 9,
   };
   auto path = std::string{vamp_style::score_music_font_path};
   auto loaded = LoadFontEx(path.c_str(), key, codepoints.data(), static_cast<std::int32_t>(codepoints.size()));
@@ -130,6 +153,10 @@ auto music_font(std::float32_t size) -> Font {
 
 auto glyph_box(std::int32_t codepoint) -> smufl_box {
   switch (codepoint) {
+  case glyph_g_clef:
+    return {.west = 0.0F, .south = -2.236F, .east = 2.656F, .north = 4.036F};
+  case glyph_f_clef:
+    return {.west = 0.0F, .south = -1.984F, .east = 3.104F, .north = 0.864F};
   case glyph_notehead_whole:
     return {.west = 0.0F, .south = -0.744684F, .east = 1.520666F, .north = 0.66F};
   case glyph_notehead_half:
@@ -158,6 +185,26 @@ auto glyph_box(std::int32_t codepoint) -> smufl_box {
     return {.west = 0.0F, .south = -1.824F, .east = 0.854F, .north = 1.848F};
   case glyph_accidental_sharp:
     return {.west = -0.088F, .south = -1.536F, .east = 1.56F, .north = 1.532F};
+  case glyph_time_sig_0:
+    return {.west = 0.08F, .south = -1.432638F, .east = 2.052F, .north = 1.436F};
+  case glyph_time_sig_0 + 1:
+    return {.west = 0.08F, .south = -1.456F, .east = 1.132F, .north = 1.464F};
+  case glyph_time_sig_0 + 2:
+    return {.west = 0.08F, .south = -1.514881F, .east = 2.641855F, .north = 1.528F};
+  case glyph_time_sig_0 + 3:
+    return {.west = 0.079297F, .south = -1.568F, .east = 2.16F, .north = 1.568F};
+  case glyph_time_sig_0 + 4:
+    return {.west = 0.08F, .south = -1.958364F, .east = 2.532314F, .north = 1.964742F};
+  case glyph_time_sig_0 + 5:
+    return {.west = 0.078655F, .south = -1.556F, .east = 2.332F, .north = 1.556F};
+  case glyph_time_sig_0 + 6:
+    return {.west = 0.08F, .south = -1.452F, .east = 2.26F, .north = 1.452F};
+  case glyph_time_sig_0 + 7:
+    return {.west = 0.081447F, .south = -1.38F, .east = 2.368F, .north = 1.38F};
+  case glyph_time_sig_0 + 8:
+    return {.west = 0.08F, .south = -1.712F, .east = 2.016604F, .north = 1.712F};
+  case glyph_time_sig_0 + 9:
+    return {.west = 0.08F, .south = -1.684F, .east = 1.976F, .north = 1.684F};
   default:
     return {};
   }
@@ -192,26 +239,22 @@ auto draw_music_origin(std::int32_t codepoint, luma::point origin, std::float32_
   DrawTextEx(font, text.c_str(), {.x = draw_x, .y = draw_y}, font_size, 0.0F, to_raylib(color));
 }
 
-auto origin_for_center(std::int32_t codepoint, std::float32_t center_x, std::float32_t center_y, std::float32_t staff_spacing) -> luma::point {
+auto origin_for_centered_baseline(std::int32_t codepoint, std::float32_t center_x, std::float32_t baseline_y, std::float32_t staff_spacing) -> luma::point {
   return {
     .x = center_x - glyph_center_x(codepoint) * staff_spacing,
-    .y = center_y + glyph_center_y(codepoint) * staff_spacing,
+    .y = baseline_y,
   };
 }
 
-auto draw_music_centered(std::int32_t codepoint, std::float32_t center_x, std::float32_t center_y, std::float32_t staff_spacing, luma::color color) -> void {
-  draw_music_origin(codepoint, origin_for_center(codepoint, center_x, center_y, staff_spacing), staff_spacing, color);
+auto draw_music_centered(std::int32_t codepoint, std::float32_t center_x, std::float32_t baseline_y, std::float32_t staff_spacing, luma::color color) -> void {
+  draw_music_origin(codepoint, origin_for_centered_baseline(codepoint, center_x, baseline_y, staff_spacing), staff_spacing, color);
 }
 
-auto draw_music_centered_at_origin_y(std::int32_t codepoint, std::float32_t center_x, std::float32_t origin_y, std::float32_t staff_spacing, luma::color color) -> void {
-  draw_music_origin(codepoint, {.x = center_x - glyph_center_x(codepoint) * staff_spacing, .y = origin_y}, staff_spacing, color);
-}
-
-auto draw_music_left_of(std::int32_t codepoint, std::float32_t right_x, std::float32_t center_y, std::float32_t staff_spacing, luma::color color) -> void {
+auto draw_music_left_of(std::int32_t codepoint, std::float32_t right_x, std::float32_t baseline_y, std::float32_t staff_spacing, luma::color color) -> void {
   auto box = glyph_box(codepoint);
   auto origin = luma::point{
     .x = right_x - box.east * staff_spacing,
-    .y = center_y + glyph_center_y(codepoint) * staff_spacing,
+    .y = baseline_y,
   };
   draw_music_origin(codepoint, origin, staff_spacing, color);
 }
@@ -359,19 +402,185 @@ auto pitch_y(vamp_zero::score_pitch const& pitch, std::float32_t staff_top, std:
   return bottom_line - static_cast<std::float32_t>(pitch_index - e4_index) * (staff_spacing * 0.5F);
 }
 
-auto accidental_glyph(std::string const& accidental) -> std::optional<std::int32_t> {
-  if (accidental == "#" || accidental == "sharp") {
-    return glyph_accidental_sharp;
-  }
-  if (accidental == "b" || accidental == "flat") {
+auto accidental_glyph(vamp_zero::score_accidental_mark mark) -> std::optional<std::int32_t> {
+  switch (mark) {
+  case vamp_zero::score_accidental_mark::FLAT:
     return glyph_accidental_flat;
-  }
-  if (accidental == "natural" || accidental == "n") {
+  case vamp_zero::score_accidental_mark::NATURAL:
     return glyph_accidental_natural;
+  case vamp_zero::score_accidental_mark::SHARP:
+    return glyph_accidental_sharp;
+  case vamp_zero::score_accidental_mark::NONE:
+    return std::nullopt;
   }
   return std::nullopt;
 }
 
+auto normalized_letter(std::char_t letter) -> std::char_t {
+  if (letter >= 'A' && letter <= 'Z') {
+    return static_cast<std::char_t>(letter + ('a' - 'A'));
+  }
+  return letter;
+}
+
+auto pitch_alteration(std::string_view accidental) -> std::int32_t {
+  if (accidental == "#" || accidental == "sharp") {
+    return 1;
+  }
+  if (accidental == "b" || accidental == "flat") {
+    return -1;
+  }
+  return 0;
+}
+
+auto alteration_mark(std::int32_t alteration) -> vamp_zero::score_accidental_mark {
+  if (alteration < 0) {
+    return vamp_zero::score_accidental_mark::FLAT;
+  }
+  if (alteration > 0) {
+    return vamp_zero::score_accidental_mark::SHARP;
+  }
+  return vamp_zero::score_accidental_mark::NATURAL;
+}
+
+auto normalized_key(std::string_view key_signature) -> std::string {
+  auto key = std::string{key_signature};
+  key.erase(std::remove(key.begin(), key.end(), ' '), key.end());
+  if (key.empty()) {
+    return "C";
+  }
+  key.front() = static_cast<std::char_t>(key.front() >= 'a' && key.front() <= 'z' ? key.front() - ('a' - 'A') : key.front());
+  for (auto index = std::size_t{1}; index < key.size(); ++index) {
+    if (key[index] >= 'A' && key[index] <= 'Z') {
+      key[index] = static_cast<std::char_t>(key[index] + ('a' - 'A'));
+    }
+  }
+  return key;
+}
+
+auto key_signature_count(std::string_view key_signature) -> std::int32_t {
+  auto key = normalized_key(key_signature);
+  if (key == "C") {
+    return 0;
+  }
+  if (key == "G") {
+    return 1;
+  }
+  if (key == "D") {
+    return 2;
+  }
+  if (key == "A") {
+    return 3;
+  }
+  if (key == "E") {
+    return 4;
+  }
+  if (key == "B") {
+    return 5;
+  }
+  if (key == "F#" || key == "Gb") {
+    return key == "F#" ? 6 : -6;
+  }
+  if (key == "C#") {
+    return 7;
+  }
+  if (key == "F") {
+    return -1;
+  }
+  if (key == "Bb") {
+    return -2;
+  }
+  if (key == "Eb") {
+    return -3;
+  }
+  if (key == "Ab") {
+    return -4;
+  }
+  if (key == "Db") {
+    return -5;
+  }
+  if (key == "Cb") {
+    return -7;
+  }
+  return 0;
+}
+
+auto key_signature_alterations(std::string_view key_signature) -> std::array<std::int32_t, 7> {
+  auto alterations = std::array<std::int32_t, 7>{};
+  constexpr auto sharp_order = std::array<std::char_t, 7>{'f', 'c', 'g', 'd', 'a', 'e', 'b'};
+  constexpr auto flat_order = std::array<std::char_t, 7>{'b', 'e', 'a', 'd', 'g', 'c', 'f'};
+  auto count = key_signature_count(key_signature);
+  if (count > 0) {
+    for (auto index = std::int32_t{}; index < count; ++index) {
+      alterations[static_cast<std::size_t>(letter_index(sharp_order[static_cast<std::size_t>(index)]))] = 1;
+    }
+  } else if (count < 0) {
+    for (auto index = std::int32_t{}; index < -count; ++index) {
+      alterations[static_cast<std::size_t>(letter_index(flat_order[static_cast<std::size_t>(index)]))] = -1;
+    }
+  }
+  return alterations;
+}
+
+struct accidental_state {
+  std::array<std::int32_t, 7> key_alterations{};
+  std::map<std::pair<std::int32_t, std::int32_t>, std::int32_t> measure_alterations{};
+};
+
+auto make_accidental_state(std::string_view key_signature) -> accidental_state {
+  return {
+    .key_alterations = key_signature_alterations(key_signature),
+  };
+}
+
+auto notated_accidental_for_pitch(accidental_state& state, vamp_zero::score_pitch const& pitch, std::bool_t tied_from_previous) -> vamp_zero::score_accidental_mark {
+  if (tied_from_previous) {
+    return vamp_zero::score_accidental_mark::NONE;
+  }
+  auto const letter = letter_index(normalized_letter(pitch.letter));
+  auto const desired = pitch_alteration(pitch.accidental);
+  auto const key = std::pair{letter, pitch.octave};
+  auto const found = state.measure_alterations.find(key);
+  auto const current = found == state.measure_alterations.end() ? state.key_alterations[static_cast<std::size_t>(letter)] : found->second;
+  if (desired == current) {
+    return vamp_zero::score_accidental_mark::NONE;
+  }
+  state.measure_alterations[key] = desired;
+  return alteration_mark(desired);
+}
+
+auto notated_accidentals_for_note(accidental_state& state, vamp_zero::score_note const& note, std::bool_t slash) -> std::vector<vamp_zero::score_accidental_mark> {
+  auto marks = std::vector<vamp_zero::score_accidental_mark>{};
+  if (note.hidden || note.kind == "rest" || slash) {
+    return marks;
+  }
+  marks.reserve(note.pitches.size());
+  for (auto const& pitch : note.pitches) {
+    marks.push_back(notated_accidental_for_pitch(state, pitch, note.tie_from_previous));
+  }
+  return marks;
+}
+
+auto effective_key_signature(vamp_zero::score_document const& score, vamp_zero::score_measure const& measure) -> std::string_view {
+  if (!measure.key_signature.empty()) {
+    return measure.key_signature;
+  }
+  if (!score.key_signature.empty()) {
+    return score.key_signature;
+  }
+  return "C";
+}
+
+auto effective_time_signature(vamp_zero::score_document const& score, vamp_zero::score_measure const* measure) -> std::string_view {
+  if (measure != nullptr && !measure->time_signature.empty()) {
+    return measure->time_signature;
+  }
+  if (!score.time_signature.empty()) {
+    return score.time_signature;
+  }
+  return "4/4";
+}
+
 auto draw_curve(luma::draw_context& context, luma::point start, luma::point control, luma::point end, std::float32_t thickness, luma::color color) -> void {
   constexpr auto segments = std::int32_t{10};
   auto previous = start;
@@ -395,6 +604,142 @@ auto draw_staff(luma::draw_context& context, std::float32_t x, std::float32_t y,
   }
 }
 
+auto normalized_clef(std::string_view clef) -> std::string {
+  auto value = std::string{clef};
+  for (auto& ch : value) {
+    if (ch >= 'A' && ch <= 'Z') {
+      ch = static_cast<std::char_t>(ch + ('a' - 'A'));
+    }
+  }
+  return value;
+}
+
+auto draw_clef(luma::draw_context&, std::string_view clef, std::float32_t x, std::float32_t staff_top, std::float32_t spacing, luma::color ink) -> std::float32_t {
+  auto name = normalized_clef(clef);
+  auto codepoint = name == "bass" || name == "f" ? glyph_f_clef : glyph_g_clef;
+  auto baseline_y = codepoint == glyph_f_clef ? staff_top + spacing : staff_top + spacing * 3.0F;
+  draw_music_origin(codepoint, {.x = x, .y = baseline_y}, spacing, ink);
+  return glyph_width(codepoint, spacing) + spacing * 0.95F;
+}
+
+auto key_signature_pitch(std::int32_t count, std::size_t index) -> vamp_zero::score_pitch {
+  constexpr auto sharp_positions = std::array<key_signature_position, 7>{{
+    {.letter = 'f', .octave = 5},
+    {.letter = 'c', .octave = 5},
+    {.letter = 'g', .octave = 5},
+    {.letter = 'd', .octave = 5},
+    {.letter = 'a', .octave = 4},
+    {.letter = 'e', .octave = 5},
+    {.letter = 'b', .octave = 4},
+  }};
+  constexpr auto flat_positions = std::array<key_signature_position, 7>{{
+    {.letter = 'b', .octave = 4},
+    {.letter = 'e', .octave = 5},
+    {.letter = 'a', .octave = 4},
+    {.letter = 'd', .octave = 5},
+    {.letter = 'g', .octave = 4},
+    {.letter = 'c', .octave = 5},
+    {.letter = 'f', .octave = 4},
+  }};
+  auto const position = count > 0 ? sharp_positions[index] : flat_positions[index];
+  return {
+    .letter = position.letter,
+    .octave = position.octave,
+  };
+}
+
+auto draw_key_signature(luma::draw_context&, std::string_view key_signature, std::float32_t x, std::float32_t staff_top, std::float32_t spacing, luma::color ink) -> std::float32_t {
+  auto count = key_signature_count(key_signature);
+  if (count == 0) {
+    return 0.0F;
+  }
+  auto const glyph = count > 0 ? glyph_accidental_sharp : glyph_accidental_flat;
+  auto const step = glyph_width(glyph, spacing) * (count > 0 ? 0.72F : 0.86F);
+  auto current_x = x;
+  auto const total = static_cast<std::size_t>(std::abs(count));
+  for (auto index = std::size_t{}; index < total; ++index) {
+    auto pitch = key_signature_pitch(count, index);
+    draw_music_origin(glyph, {.x = current_x, .y = pitch_y(pitch, staff_top, spacing)}, spacing, ink);
+    current_x += step;
+  }
+  return current_x - x + spacing * 0.45F;
+}
+
+auto time_signature_digit(std::char_t digit) -> std::optional<std::int32_t> {
+  if (digit < '0' || digit > '9') {
+    return std::nullopt;
+  }
+  return glyph_time_sig_0 + static_cast<std::int32_t>(digit - '0');
+}
+
+auto time_signature_run_width(std::string_view text, std::float32_t spacing) -> std::float32_t {
+  auto width = std::float32_t{};
+  for (auto digit : text) {
+    auto codepoint = time_signature_digit(digit);
+    if (!codepoint) {
+      continue;
+    }
+    if (width > 0.0F) {
+      width += spacing * 0.16F;
+    }
+    width += glyph_width(*codepoint, spacing);
+  }
+  return width;
+}
+
+auto draw_time_signature_run(std::string_view text, std::float32_t x, std::float32_t baseline_y, std::float32_t spacing, luma::color ink) -> void {
+  auto current_x = x;
+  for (auto digit : text) {
+    auto codepoint = time_signature_digit(digit);
+    if (!codepoint) {
+      continue;
+    }
+    draw_music_origin(*codepoint, {.x = current_x, .y = baseline_y}, spacing, ink);
+    current_x += glyph_width(*codepoint, spacing) + spacing * 0.16F;
+  }
+}
+
+auto draw_time_signature(luma::draw_context&, std::string_view time_signature, std::float32_t x, std::float32_t staff_top, std::float32_t spacing, luma::color ink) -> std::float32_t {
+  auto slash = time_signature.find('/');
+  if (slash == std::string_view::npos) {
+    return 0.0F;
+  }
+  auto numerator = time_signature.substr(0, slash);
+  auto denominator = time_signature.substr(slash + 1U);
+  auto numerator_width = time_signature_run_width(numerator, spacing);
+  auto denominator_width = time_signature_run_width(denominator, spacing);
+  auto width = std::max(numerator_width, denominator_width);
+  if (width <= 0.0F) {
+    return 0.0F;
+  }
+  draw_time_signature_run(numerator, x + (width - numerator_width) * 0.5F, staff_top + spacing, spacing, ink);
+  draw_time_signature_run(denominator, x + (width - denominator_width) * 0.5F, staff_top + spacing * 3.0F, spacing, ink);
+  return width + spacing * 0.95F;
+}
+
+auto draw_system_preamble(
+  luma::draw_context& context,
+  vamp_zero::score_document const& score,
+  vamp_zero::score_measure const* first_measure,
+  std::float32_t x,
+  std::float32_t staff_top,
+  std::float32_t spacing,
+  std::bool_t show_time_signature
+) -> std::float32_t {
+  auto ink = vamp_zero::to_luma(vamp_style::paper_ink);
+  auto current_x = x + spacing * 0.35F;
+  current_x += draw_clef(context, score.clef, current_x, staff_top, spacing, ink);
+  auto key_width = draw_key_signature(context, first_measure == nullptr ? score.key_signature : effective_key_signature(score, *first_measure), current_x, staff_top, spacing, ink);
+  current_x += key_width;
+  if (key_width == 0.0F) {
+    current_x += spacing * 0.35F;
+  }
+  if (show_time_signature) {
+    current_x += draw_time_signature(context, effective_time_signature(score, first_measure), current_x, staff_top, spacing, ink);
+  }
+  return current_x + spacing * 0.25F;
+}
+
 auto draw_duration_dot(luma::draw_context& context, std::float32_t x, std::float32_t y, std::float32_t spacing, luma::color ink) -> void {
   static_cast<void>(context);
   draw_music_centered(glyph_augmentation_dot, x, y, spacing, ink);
@@ -450,7 +795,7 @@ auto draw_rest(luma::draw_context& context, duration_shape duration, std::float3
   if (centered) {
     draw_music_centered(codepoint, x, center, spacing, ink);
   } else {
-    draw_music_centered_at_origin_y(codepoint, x, origin_y, spacing, ink);
+    draw_music_centered(codepoint, x, origin_y, spacing, ink);
   }
   if (duration.dots != 0) {
     draw_duration_dot(context, x + glyph_width(codepoint, spacing) * 0.5F + spacing, center, spacing, ink);
@@ -475,12 +820,21 @@ auto notehead_codepoint(duration_shape duration, std::bool_t slash) -> std::int3
 
 auto draw_notehead(duration_shape duration, std::bool_t slash, std::float32_t x, std::float32_t y, std::float32_t spacing, luma::color ink) -> notehead_instance {
   auto codepoint = notehead_codepoint(duration, slash);
-  auto origin = origin_for_center(codepoint, x, y, spacing);
+  auto origin = origin_for_centered_baseline(codepoint, x, y, spacing);
   draw_music_origin(codepoint, origin, spacing, ink);
   return {.center_y = y, .origin = origin};
 }
 
-auto draw_note(luma::draw_context& context, vamp_zero::score_note const& note, std::float32_t x, std::float32_t staff_top, std::float32_t spacing, std::float32_t next_x, std::bool_t slash) -> void {
+auto draw_note(
+  luma::draw_context& context,
+  vamp_zero::score_note const& note,
+  std::float32_t x,
+  std::float32_t staff_top,
+  std::float32_t spacing,
+  std::float32_t next_x,
+  std::bool_t slash,
+  std::vector<vamp_zero::score_accidental_mark> const& accidentals
+) -> void {
   if (note.hidden) {
     return;
   }
@@ -508,11 +862,13 @@ auto draw_note(luma::draw_context& context, vamp_zero::score_note const& note, s
       low_y = std::max(low_y, yy);
       high_y = std::min(high_y, yy);
     }
-    for (auto const& pitch : note.pitches) {
+    for (auto pitch_index = std::size_t{}; pitch_index < note.pitches.size(); ++pitch_index) {
+      auto const& pitch = note.pitches[pitch_index];
       auto yy = std::clamp(pitch_y(pitch, staff_top, spacing), staff_top - spacing * 2.0F, bottom + spacing * 2.0F);
       draw_ledger_lines(context, x, yy, staff_top, spacing, ink);
-      if (auto accidental = accidental_glyph(pitch.accidental)) {
-        auto head_origin = origin_for_center(notehead_codepoint(duration, false), x, yy, spacing);
+      auto mark = pitch_index < accidentals.size() ? accidentals[pitch_index] : vamp_zero::score_accidental_mark::NONE;
+      if (auto accidental = accidental_glyph(mark)) {
+        auto head_origin = origin_for_centered_baseline(notehead_codepoint(duration, false), x, yy, spacing);
         auto head_left = head_origin.x + glyph_box(notehead_codepoint(duration, false)).west * spacing;
         draw_music_left_of(*accidental, head_left - spacing * 0.65F, yy, spacing, ink);
       }
@@ -524,7 +880,7 @@ auto draw_note(luma::draw_context& context, vamp_zero::score_note const& note, s
   if (has_stem(duration) && !heads.empty()) {
     auto stem_up = (low_y + high_y) * 0.5F >= center;
     if (stem_up) {
-      auto base_origin = origin_for_center(notehead, x, low_y, spacing);
+      auto base_origin = origin_for_centered_baseline(notehead, x, low_y, spacing);
       auto base = anchor_point(base_origin, stem_up_anchor(notehead), spacing);
       auto stem_top = std::min(high_y, center) - spacing * 3.6F;
       context.stroke_line(base, {.x = base.x, .y = stem_top}, 1.6F, ink);
@@ -532,7 +888,7 @@ auto draw_note(luma::draw_context& context, vamp_zero::score_note const& note, s
         draw_eighth_flag(true, base.x, stem_top, spacing, ink);
       }
     } else {
-      auto base_origin = origin_for_center(notehead, x, high_y, spacing);
+      auto base_origin = origin_for_centered_baseline(notehead, x, high_y, spacing);
       auto base = anchor_point(base_origin, stem_down_anchor(notehead), spacing);
       auto stem_bottom = std::max(low_y, center) + spacing * 3.6F;
       context.stroke_line(base, {.x = base.x, .y = stem_bottom}, 1.6F, ink);
@@ -543,7 +899,7 @@ auto draw_note(luma::draw_context& context, vamp_zero::score_note const& note, s
   }
 
   if (duration.dots != 0) {
-    auto dot_origin = origin_for_center(notehead, x, low_y, spacing);
+    auto dot_origin = origin_for_centered_baseline(notehead, x, low_y, spacing);
     auto dot_x = dot_origin.x + glyph_box(notehead).east * spacing + spacing * 0.85F;
     draw_duration_dot(context, dot_x, dot_y_for(low_y, staff_top, spacing), spacing, ink);
   }
@@ -558,22 +914,26 @@ auto note_x(std::float32_t start_x, std::float32_t width, std::int64_t total_tic
   return start_x + width * ratio;
 }
 
-auto draw_measure(luma::draw_context& context, vamp_zero::score_measure const& measure, luma::rect bounds, std::size_t measure_number) -> void {
-  constexpr auto spacing = std::float32_t{8.0F};
-  auto staff_top = bounds.y + 52.0F;
-  draw_text(context, bounds.x + 5.0F, bounds.y + 1.0F, std::to_string(measure_number), 1, vamp_style::muted, 42.0F);
+auto draw_measure(
+  luma::draw_context& context,
+  vamp_zero::score_document const& score,
+  vamp_zero::score_measure const& measure,
+  luma::rect bounds,
+  std::size_t measure_number,
+  std::float32_t staff_top,
+  std::float32_t spacing
+) -> void {
+  draw_text(context, bounds.x + spacing * 0.2F, bounds.y + spacing * 0.05F, std::to_string(measure_number), 1, vamp_style::muted, spacing * 4.0F);
   if (!measure.section_label.empty()) {
-    draw_text(context, bounds.x + 28.0F, bounds.y - 2.0F, measure.section_label, 2, vamp_style::selection, bounds.width - 32.0F);
-  }
-  if (!measure.time_signature.empty() && measure_number == 1U) {
-    draw_text(context, bounds.x + 8.0F, staff_top + 2.0F, measure.time_signature, 1, vamp_style::paper_ink, 42.0F);
+    draw_text(context, bounds.x + spacing * 2.3F, bounds.y - spacing * 0.25F, measure.section_label, 2, vamp_style::selection, bounds.width - spacing * 2.7F);
   }
 
-  auto notation_x = bounds.x + (measure_number == 1U ? 43.0F : 24.0F);
-  auto notation_width = std::max(24.0F, bounds.width - (notation_x - bounds.x) - 16.0F);
+  auto notation_x = bounds.x + spacing * 1.4F;
+  auto notation_width = std::max(spacing * 3.0F, bounds.width - (notation_x - bounds.x) - spacing);
   auto total_ticks = measure_ticks(measure);
   auto elapsed = std::int64_t{};
   auto previous_chord = std::string{};
+  auto accidentals = make_accidental_state(effective_key_signature(score, measure));
   for (auto index = std::size_t{}; index < measure.notes.size(); ++index) {
     auto const& note = measure.notes[index];
     auto duration_ticks = spacing_ticks(note);
@@ -581,12 +941,14 @@ auto draw_measure(luma::draw_context& context, vamp_zero::score_measure const& m
     auto next_duration = index + 1U < measure.notes.size() ? spacing_ticks(measure.notes[index + 1U]) : duration_ticks;
     auto next_x = note_x(notation_x, notation_width, total_ticks, elapsed + duration_ticks, next_duration);
     if (!note.hidden && !note.chord_symbol.empty() && note.chord_symbol != previous_chord) {
-      draw_text(context, x - 18.0F, bounds.y + 24.0F, note.chord_symbol, 2, vamp_style::paper_ink, std::min(92.0F, bounds.width - (x - bounds.x)));
+      draw_text(context, x - spacing * 1.5F, bounds.y + spacing * 2.0F, note.chord_symbol, 2, vamp_style::paper_ink, std::min(spacing * 10.0F, bounds.width - (x - bounds.x)));
       previous_chord = note.chord_symbol;
     }
-    draw_note(context, note, x, staff_top, spacing, next_x, note.notehead == "slash");
+    auto const slash = note.notehead == "slash";
+    auto accidental_marks = notated_accidentals_for_note(accidentals, note, slash);
+    draw_note(context, note, x, staff_top, spacing, next_x, slash, accidental_marks);
     if (!note.hidden && !note.lyric.empty()) {
-      draw_text(context, x - 12.0F, staff_top + 46.0F, note.lyric, 1, vamp_style::muted, 66.0F);
+      draw_text(context, x - spacing, staff_top + spacing * 5.4F, note.lyric, 1, vamp_style::muted, spacing * 8.0F);
     }
     elapsed += duration_ticks;
   }
@@ -594,11 +956,22 @@ auto draw_measure(luma::draw_context& context, vamp_zero::score_measure const& m
 
 }
 
+auto vamp_zero::notated_accidentals_for_measure(vamp_zero::score_measure const& measure, std::string_view inherited_key_signature) -> std::vector<vamp_zero::score_accidental_mark> {
+  auto state = make_accidental_state(measure.key_signature.empty() ? inherited_key_signature : measure.key_signature);
+  auto accidentals = std::vector<vamp_zero::score_accidental_mark>{};
+  for (auto const& note : measure.notes) {
+    auto marks = notated_accidentals_for_note(state, note, note.notehead == "slash");
+    accidentals.insert(accidentals.end(), marks.begin(), marks.end());
+  }
+  return accidentals;
+}
+
 auto vamp_zero::draw_score_page(luma::draw_context& context, luma::rect bounds, vamp_zero::score_document const& score, std::size_t page_index) -> void {
   context.fill_rect(bounds, vamp_zero::to_luma(vamp_style::paper));
   context.stroke_rect(bounds, 2.0F, vamp_zero::to_luma(vamp_style::rule));
   context.push_clip(bounds);
 
+  constexpr auto spacing = std::float32_t{12.0F};
   auto margin = std::float32_t{28.0F};
   auto header_y = bounds.y + 16.0F;
   draw_text(context, bounds.x + margin, header_y, score.title, 3, vamp_style::paper_ink, bounds.width * 0.55F);
@@ -610,22 +983,26 @@ auto vamp_zero::draw_score_page(luma::draw_context& context, luma::rect bounds,
   auto content_y = bounds.y + 84.0F;
   auto content_width = bounds.width - margin * 2.0F;
   auto system_height = (bounds.height - 108.0F) / static_cast<std::float32_t>(vamp_zero::score_systems_per_page);
-  auto measure_width = content_width / static_cast<std::float32_t>(vamp_zero::score_measures_per_system);
   auto first_measure = page_index * vamp_zero::score_measures_per_page;
 
   for (auto system = std::size_t{}; system < vamp_zero::score_systems_per_page; ++system) {
     auto system_y = content_y + static_cast<std::float32_t>(system) * system_height;
-    auto staff_top = system_y + 52.0F;
-    draw_staff(context, content_x, staff_top, content_width, 8.0F);
+    auto staff_top = system_y + spacing * 4.25F;
+    auto system_first_measure = first_measure + system * vamp_zero::score_measures_per_system;
+    auto const* first_system_measure = system_first_measure < score.measures.size() ? &score.measures[system_first_measure] : nullptr;
+    draw_staff(context, content_x, staff_top, content_width, spacing);
+    auto measure_start_x = draw_system_preamble(context, score, first_system_measure, content_x, staff_top, spacing, page_index == 0U && system == 0U);
+    auto measure_area_width = std::max(spacing * 12.0F, content_x + content_width - measure_start_x);
+    auto measure_width = measure_area_width / static_cast<std::float32_t>(vamp_zero::score_measures_per_system);
     for (auto measure = std::size_t{}; measure < vamp_zero::score_measures_per_system; ++measure) {
-      auto measure_index = first_measure + system * vamp_zero::score_measures_per_system + measure;
-      auto x = content_x + static_cast<std::float32_t>(measure) * measure_width;
-      context.stroke_line({.x = x, .y = staff_top}, {.x = x, .y = staff_top + 32.0F}, 1.2F, vamp_zero::to_luma(vamp_style::paper_ink));
+      auto measure_index = system_first_measure + measure;
+      auto x = measure_start_x + static_cast<std::float32_t>(measure) * measure_width;
+      context.stroke_line({.x = x, .y = staff_top}, {.x = x, .y = staff_top + spacing * 4.0F}, 1.2F, vamp_zero::to_luma(vamp_style::paper_ink));
       if (measure_index < score.measures.size()) {
-        draw_measure(context, score.measures[measure_index], {.x = x, .y = system_y, .width = measure_width, .height = system_height}, measure_index + 1U);
+        draw_measure(context, score, score.measures[measure_index], {.x = x, .y = system_y, .width = measure_width, .height = system_height}, measure_index + 1U, staff_top, spacing);
       }
     }
-    context.stroke_line({.x = content_x + content_width, .y = staff_top}, {.x = content_x + content_width, .y = staff_top + 32.0F}, 2.0F, vamp_zero::to_luma(vamp_style::paper_ink));
+    context.stroke_line({.x = content_x + content_width, .y = staff_top}, {.x = content_x + content_width, .y = staff_top + spacing * 4.0F}, 2.0F, vamp_zero::to_luma(vamp_style::paper_ink));
   }
 
   context.pop_clip();
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 0000000..f1eed4c
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,20 @@
+add_executable(product-vamp-test
+  test.cpp
+)
+target_include_directories(product-vamp-test PRIVATE
+  ${CMAKE_CURRENT_SOURCE_DIR}
+)
+target_link_libraries(product-vamp-test PRIVATE
+  vamp-zero-core
+)
+target_compile_features(product-vamp-test PRIVATE cxx_std_23)
+add_test(NAME product-vamp COMMAND product-vamp-test)
+set_tests_properties(product-vamp PROPERTIES TIMEOUT 60)
+add_custom_target(check
+  COMMAND ${CMAKE_CTEST_COMMAND}
+    --test-dir ${CMAKE_BINARY_DIR}
+    -R ^product-vamp$
+    --output-on-failure
+    --timeout 60
+  USES_TERMINAL
+)
diff --git a/tests/test.cpp b/tests/test.cpp
new file mode 100644
index 0000000..92ce306
--- /dev/null
+++ b/tests/test.cpp
@@ -0,0 +1,218 @@
+#include <test.hpp>
+
+#include <initializer_list>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include <vamp_zero/library.hpp>
+#include <vamp_zero/score.hpp>
+#include <vamp_zero/types.hpp>
+
+namespace {
+
+auto pitch(std::char_t letter, std::string accidental, std::int32_t octave = 4) -> vamp_zero::score_pitch {
+  return {
+    .letter = letter,
+    .octave = octave,
+    .accidental = std::move(accidental),
+  };
+}
+
+auto note(
+  std::initializer_list<vamp_zero::score_pitch> pitches,
+  std::bool_t tie_from_previous = false,
+  std::string notehead = {},
+  std::bool_t hidden = false
+) -> vamp_zero::score_note {
+  return {
+    .kind = "note",
+    .hidden = hidden,
+    .duration_ticks = 4096,
+    .display_ticks = 4096,
+    .notehead = std::move(notehead),
+    .tie_from_previous = tie_from_previous,
+    .pitches = std::vector<vamp_zero::score_pitch>{pitches},
+  };
+}
+
+auto rest(std::initializer_list<vamp_zero::score_pitch> pitches) -> vamp_zero::score_note {
+  return {
+    .kind = "rest",
+    .duration_ticks = 4096,
+    .display_ticks = 4096,
+    .pitches = std::vector<vamp_zero::score_pitch>{pitches},
+  };
+}
+
+auto mark_name(vamp_zero::score_accidental_mark mark) -> std::string {
+  switch (mark) {
+  case vamp_zero::score_accidental_mark::NONE:
+    return "none";
+  case vamp_zero::score_accidental_mark::FLAT:
+    return "flat";
+  case vamp_zero::score_accidental_mark::NATURAL:
+    return "natural";
+  case vamp_zero::score_accidental_mark::SHARP:
+    return "sharp";
+  }
+  return {};
+}
+
+auto mark_names(std::vector<vamp_zero::score_accidental_mark> const& marks) -> std::vector<std::string> {
+  auto names = std::vector<std::string>{};
+  names.reserve(marks.size());
+  for (auto mark : marks) {
+    names.push_back(mark_name(mark));
+  }
+  return names;
+}
+
+void expect_marks(std::vector<vamp_zero::score_accidental_mark> const& marks, std::initializer_list<std::string_view> expected) {
+  auto actual_names = mark_names(marks);
+  BOOST_REQUIRE_EQUAL(actual_names.size(), expected.size());
+  auto index = std::size_t{};
+  for (auto name : expected) {
+    BOOST_TEST(actual_names[index] == std::string{name});
+    ++index;
+  }
+}
+
+}
+
+BOOST_AUTO_TEST_CASE(score_parser_preserves_notation_preamble) {
+  auto parsed = vamp_zero::parse_score_document(R"json(
+{
+  "version": 1,
+  "metadata": {
+    "title": "Standard Tune",
+    "composer": "Composer",
+    "key_signature": "Eb",
+    "time_signature": "3/4"
+  },
+  "staves": [
+    {
+      "id": "staff-lead",
+      "name": "Lead",
+      "clef": "treble",
+      "role": "lead",
+      "measures": [
+        {
+          "id": "measure-1",
+          "time_signature": "3/4",
+          "key_signature": "Eb",
+          "voices": [
+            {
+              "id": "voice-1",
+              "notes": [
+                {
+                  "id": "note-1",
+                  "kind": "note",
+                  "duration_ticks": 4096,
+                  "pitches": [
+                    {
+                      "letter": "b",
+                      "octave": 4,
+                      "accidental": "b"
+                    }
+                  ]
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}
+)json", "standard-tune.json");
+
+  BOOST_REQUIRE(static_cast<std::bool_t>(parsed));
+  BOOST_TEST(parsed->title == "Standard Tune");
+  BOOST_TEST(parsed->composer == "Composer");
+  BOOST_TEST(parsed->key_signature == "Eb");
+  BOOST_TEST(parsed->time_signature == "3/4");
+  BOOST_TEST(parsed->clef == "treble");
+  BOOST_TEST(parsed->part == "Lead");
+  BOOST_REQUIRE_EQUAL(parsed->measures.size(), 1U);
+  BOOST_TEST(parsed->measures.front().key_signature == "Eb");
+  BOOST_TEST(parsed->measures.front().time_signature == "3/4");
+}
+
+BOOST_AUTO_TEST_CASE(accidentals_are_suppressed_when_the_key_signature_already_covers_the_pitch) {
+  auto c_major = vamp_zero::score_measure{
+    .key_signature = "C",
+    .notes = {
+      note({pitch('c', "n")}),
+      note({pitch('d', "n")}),
+      note({pitch('e', "n")}),
+    },
+  };
+  expect_marks(vamp_zero::notated_accidentals_for_measure(c_major, "C"), {"none", "none", "none"});
+
+  auto f_major = vamp_zero::score_measure{
+    .key_signature = "F",
+    .notes = {
+      note({pitch('b', "b")}),
+      note({pitch('e', "n")}),
+    },
+  };
+  expect_marks(vamp_zero::notated_accidentals_for_measure(f_major, "C"), {"none", "none"});
+
+  auto d_major = vamp_zero::score_measure{
+    .key_signature = "D",
+    .notes = {
+      note({pitch('f', "#")}),
+      note({pitch('c', "#")}),
+    },
+  };
+  expect_marks(vamp_zero::notated_accidentals_for_measure(d_major, "C"), {"none", "none"});
+}
+
+BOOST_AUTO_TEST_CASE(accidentals_follow_measure_state_after_the_first_printed_change) {
+  auto measure = vamp_zero::score_measure{
+    .key_signature = "F",
+    .notes = {
+      note({pitch('b', "b")}),
+      note({pitch('b', "n")}),
+      note({pitch('b', "n")}),
+      note({pitch('b', "b")}),
+      note({pitch('b', "b")}),
+    },
+  };
+  expect_marks(vamp_zero::notated_accidentals_for_measure(measure, "C"), {"none", "natural", "none", "flat", "none"});
+}
+
+BOOST_AUTO_TEST_CASE(measure_state_resets_for_each_measure) {
+  auto first = vamp_zero::score_measure{
+    .key_signature = "C",
+    .notes = {
+      note({pitch('f', "#")}),
+      note({pitch('f', "#")}),
+    },
+  };
+  expect_marks(vamp_zero::notated_accidentals_for_measure(first, "C"), {"sharp", "none"});
+
+  auto second = vamp_zero::score_measure{
+    .key_signature = "C",
+    .notes = {
+      note({pitch('f', "#")}),
+    },
+  };
+  expect_marks(vamp_zero::notated_accidentals_for_measure(second, "C"), {"sharp"});
+}
+
+BOOST_AUTO_TEST_CASE(tied_rests_hidden_and_slash_notes_do_not_emit_accidentals) {
+  auto measure = vamp_zero::score_measure{
+    .key_signature = "C",
+    .notes = {
+      note({pitch('f', "#")}, true),
+      rest({pitch('b', "b")}),
+      note({pitch('c', "#")}, false, "slash"),
+      note({pitch('d', "#")}, false, {}, true),
+      note({pitch('e', "b")}),
+    },
+  };
+  expect_marks(vamp_zero::notated_accidentals_for_measure(measure, "C"), {"none", "flat"});
+}
diff --git a/tests/test.hpp b/tests/test.hpp
new file mode 100644
index 0000000..581973e
--- /dev/null
+++ b/tests/test.hpp
@@ -0,0 +1,4 @@
+#pragma once
+
+#define BOOST_TEST_MODULE product_vamp
+#include <boost/test/included/unit_test.hpp>