Add tests for accessing host from function callbacks

Author: kraenhansen

packages/weak-node-api/tests/test_inject.cpp

@@ -23,3 +23,42 @@ TEST_CASE("inject_weak_node_api_host") {
     REQUIRE(called);
   }
 }
+
+TEST_CASE("calling into host from functions") {
+  auto my_create_function = [](napi_env arg0, const char *arg1, size_t arg2,
+                               napi_callback arg3, void *arg4,
+                               napi_value *arg5) -> napi_status {
+    // This is a failing noop as we're not actually creating a JS functions
+    return napi_status::napi_generic_failure;
+  };
+  NodeApiHost host{.napi_create_function = my_create_function};
+  inject_weak_node_api_host(host);
+  napi_env raw_env{};
+
+  SECTION("directly") {
+    napi_value result;
+    napi_callback cb = [](napi_env env, napi_callback_info info) -> napi_value {
+      napi_value obj;
+      napi_status status = napi_create_object(env, &obj);
+      return obj;
+    };
+
+    napi_create_function(raw_env, "foo", 3, cb, nullptr, &result);
+  }
+
+  SECTION("via callback info") {
+    napi_value result;
+    napi_callback cb = [](napi_env env, napi_callback_info info) -> napi_value {
+      // Get host via callback info
+      void *data;
+      napi_get_cb_info(env, info, nullptr, nullptr, nullptr, &data);
+      auto *host_ptr = static_cast<decltype(&host)>(data);
+
+      napi_value obj;
+      napi_status status = host_ptr->napi_create_object(env, &obj);
+      return obj;
+    };
+
+    napi_create_function(raw_env, "foo", 3, cb, &host, &result);
+  }
+}