diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index f24d9c04..ecff59bd 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -76,6 +76,32 @@ jobs:
       - run: npm ci
       - run: npm run bootstrap
       - run: npm test
+  weak-node-api-tests:
+    if: github.ref == 'refs/heads/main' || contains(github.event.pull_request.labels.*.name, 'weak-node-api')
+    strategy:
+      fail-fast: false
+      matrix:
+        runner:
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
+    runs-on: ${{ matrix.runner }}
+    name: Weak Node-API tests (${{ matrix.runner }})
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: lts/jod
+      - run: npm ci
+      - run: npm run build
+      - name: Prepare weak-node-api
+        run: npm run prepare-weak-node-api --workspace weak-node-api
+      - name: Build and run weak-node-api C++ tests
+        run: |
+          cmake -S . -B build -DBUILD_TESTS=ON
+          cmake --build build
+          ctest --test-dir build --output-on-failure
+        working-directory: packages/weak-node-api
   test-ios:
     if: github.ref == 'refs/heads/main' || contains(github.event.pull_request.labels.*.name, 'Apple 🍎')
     name: Test app (iOS)
diff --git a/packages/weak-node-api/.gitignore b/packages/weak-node-api/.gitignore
index 30ea0716..5cc9e939 100644
--- a/packages/weak-node-api/.gitignore
+++ b/packages/weak-node-api/.gitignore
@@ -9,3 +9,6 @@
 
 # Copied from node-api-headers by scripts/copy-node-api-headers.ts
 /include/
+
+# Clang cache
+/.cache/
diff --git a/packages/weak-node-api/CMakeLists.txt b/packages/weak-node-api/CMakeLists.txt
index e53c71cd..d61630f2 100644
--- a/packages/weak-node-api/CMakeLists.txt
+++ b/packages/weak-node-api/CMakeLists.txt
@@ -38,10 +38,17 @@ if(APPLE)
   )
 endif()
 
-target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_17)
+# C++20 is needed to use designated initializers
+target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_20)
 target_compile_definitions(${PROJECT_NAME} PRIVATE NAPI_VERSION=8)
 
 target_compile_options(${PROJECT_NAME} PRIVATE
   $<$<CXX_COMPILER_ID:MSVC>:/W4 /WX>
   $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wall -Wextra -Werror>
 )
+
+option(BUILD_TESTS "Build the tests" OFF)
+if(BUILD_TESTS)
+  enable_testing()
+  add_subdirectory(tests)
+endif()
diff --git a/packages/weak-node-api/scripts/generate-weak-node-api.ts b/packages/weak-node-api/scripts/generate-weak-node-api.ts
index b9a8736c..b47aed27 100644
--- a/packages/weak-node-api/scripts/generate-weak-node-api.ts
+++ b/packages/weak-node-api/scripts/generate-weak-node-api.ts
@@ -18,13 +18,24 @@ export function generateHeader(functions: FunctionDecl[]) {
     "#include <node_api.h>", // Node-API
     "#include <stdio.h>", // fprintf()
     "#include <stdlib.h>", // abort()
+    "",
+    // Ideally we would have just used NAPI_NO_RETURN, but
+    // __declspec(noreturn) (when building with Microsoft Visual C++) cannot be used on members of a struct
+    // TODO: If we targeted C++23 we could use std::unreachable()
+    "#if defined(__GNUC__)",
+    "#define WEAK_NODE_API_UNREACHABLE __builtin_unreachable();",
+    "#else",
+    "#define WEAK_NODE_API_UNREACHABLE __assume(0);",
+    "#endif",
+    "",
     // Generate the struct of function pointers
     "struct WeakNodeApiHost {",
-    ...functions.map(
-      ({ returnType, noReturn, name, argumentTypes }) =>
-        `${returnType} ${
-          noReturn ? " __attribute__((noreturn))" : ""
-        }(*${name})(${argumentTypes.join(", ")});`,
+    ...functions.map(({ returnType, name, argumentTypes }) =>
+      [
+        returnType,
+        // Signature
+        `(*${name})(${argumentTypes.join(", ")});`,
+      ].join(" "),
     ),
     "};",
     "typedef void(*InjectHostFunction)(const WeakNodeApiHost&);",
@@ -46,25 +57,26 @@ export function generateSource(functions: FunctionDecl[]) {
     "};",
     ``,
     // Generate function calling into the host
-    ...functions.flatMap(({ returnType, noReturn, name, argumentTypes }) => {
+    ...functions.flatMap(({ returnType, name, argumentTypes, noReturn }) => {
       return [
-        `extern "C" ${returnType} ${
-          noReturn ? " __attribute__((noreturn))" : ""
-        }${name}(${argumentTypes
-          .map((type, index) => `${type} arg${index}`)
-          .join(", ")}) {`,
+        'extern "C"',
+        returnType,
+        name,
+        "(",
+        argumentTypes.map((type, index) => `${type} arg${index}`).join(", "),
+        ") {",
         `if (g_host.${name} == nullptr) {`,
         `  fprintf(stderr, "Node-API function '${name}' called before it was injected!\\n");`,
         "  abort();",
         "}",
-        (returnType === "void" ? "" : "return ") +
-          "g_host." +
-          name +
-          "(" +
-          argumentTypes.map((_, index) => `arg${index}`).join(", ") +
-          ");",
+        returnType === "void" ? "" : "return ",
+        `g_host.${name}`,
+        "(",
+        argumentTypes.map((_, index) => `arg${index}`).join(", "),
+        ");",
+        noReturn ? "WEAK_NODE_API_UNREACHABLE" : "",
         "};",
-      ];
+      ].join(" ");
     }),
   ].join("\n");
 }
diff --git a/packages/weak-node-api/tests/CMakeLists.txt b/packages/weak-node-api/tests/CMakeLists.txt
new file mode 100644
index 00000000..89b19f84
--- /dev/null
+++ b/packages/weak-node-api/tests/CMakeLists.txt
@@ -0,0 +1,27 @@
+Include(FetchContent)
+
+FetchContent_Declare(
+  Catch2
+  GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+  GIT_TAG v3.11.0
+)
+
+FetchContent_MakeAvailable(Catch2)
+
+add_executable(weak-node-api-tests
+  test_inject.cpp
+)
+target_link_libraries(weak-node-api-tests
+  PRIVATE
+    weak-node-api
+    Catch2::Catch2WithMain
+)
+
+target_compile_features(weak-node-api-tests PRIVATE cxx_std_20)
+target_compile_definitions(weak-node-api-tests PRIVATE NAPI_VERSION=8)
+
+# As per https://github.com/catchorg/Catch2/blob/devel/docs/cmake-integration.md#catchcmake-and-catchaddtestscmake
+list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
+include(CTest)
+include(Catch)
+catch_discover_tests(weak-node-api-tests)
diff --git a/packages/weak-node-api/tests/test_inject.cpp b/packages/weak-node-api/tests/test_inject.cpp
new file mode 100644
index 00000000..e2101c8c
--- /dev/null
+++ b/packages/weak-node-api/tests/test_inject.cpp
@@ -0,0 +1,25 @@
+#include <catch2/catch_test_macros.hpp>
+#include <weak_node_api.hpp>
+
+TEST_CASE("inject_weak_node_api_host") {
+  SECTION("is callable") {
+    WeakNodeApiHost host{};
+    inject_weak_node_api_host(host);
+  }
+
+  SECTION("propagates calls to napi_create_object") {
+    static bool called = false;
+    auto my_create_object = [](napi_env env,
+                               napi_value *result) -> napi_status {
+      called = true;
+      return napi_status::napi_ok;
+    };
+    WeakNodeApiHost host{.napi_create_object = my_create_object};
+    inject_weak_node_api_host(host);
+
+    napi_value result;
+    napi_create_object({}, &result);
+
+    REQUIRE(called);
+  }
+}