diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 245a5c8c8..6f57713ca 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -209,6 +209,22 @@ cet_test(
   LIBRARIES
   phlex::core_internal
 )
+cet_test(
+  transform_node
+  USE_CATCH2_MAIN
+  SOURCE
+  transform_node_test.cpp
+  LIBRARIES
+  phlex::core_internal
+)
+cet_test(
+  multilayer_join
+  USE_CATCH2_MAIN
+  SOURCE
+  multilayer_join_test.cpp
+  LIBRARIES
+  phlex::core_internal
+)
 cet_test(
   replicated
   USE_CATCH2_MAIN
diff --git a/test/multilayer_join_test.cpp b/test/multilayer_join_test.cpp
new file mode 100644
index 000000000..d8300f01e
--- /dev/null
+++ b/test/multilayer_join_test.cpp
@@ -0,0 +1,99 @@
+#include "phlex/core/multilayer_join_node.hpp"
+#include "phlex/model/data_cell_index.hpp"
+#include "phlex/model/product_store.hpp"
+
+#include "catch2/catch_test_macros.hpp"
+#include "oneapi/tbb/flow_graph.h"
+
+#include <memory>
+#include <string>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+using namespace phlex;
+using namespace phlex::detail;
+using namespace phlex::experimental;
+
+namespace {
+  constexpr auto message_id = 42u;
+
+  struct input_type_1 {
+    int value;
+  };
+
+  struct input_type_2 {
+    int value;
+  };
+
+  template <typename T>
+  product_specification spec(char const* creator, char const* suffix)
+  {
+    return {algorithm_name{creator}, identifier{suffix}, make_type_id<T>()};
+  }
+
+  template <typename T>
+  product_store_ptr store_with_product(char const* creator, char const* suffix, T value)
+  {
+    auto store = product_store::base(creator);
+    store->add_product(spec<T>(creator, suffix), std::move(value));
+    return store;
+  }
+}
+
+TEST_CASE("multilayer_join_node joins multiple input products", "[join]")
+{
+  oneapi::tbb::flow::graph graph;
+  auto left_store = store_with_product("left_input", "", input_type_1{17});
+  auto right_store = store_with_product("right_input", "", input_type_2{25});
+
+  // Force repeaters by passing distinct layer names.
+  // The actual routing is performed by matching index hashes between data, index, and flush.
+  auto join = multilayer_join_node<2>{
+    graph,
+    "multilayer_join_test",
+    std::vector<identifier>{identifier{"left_layer"}, identifier{"right_layer"}}};
+
+  oneapi::tbb::flow::queue_node<message_tuple<2>> sink{graph};
+  make_edge(output_port<0>(join), sink);
+
+  auto& left_port = receiver_for<0ull, 2>(join, 0u);
+  auto& right_port = receiver_for<0ull, 2>(join, 1u);
+
+  REQUIRE(left_port.try_put({.store = left_store, .id = message_id}));
+  graph.wait_for_all();
+
+  message_tuple<2> output;
+  CHECK_FALSE(sink.try_get(output));
+
+  REQUIRE(right_port.try_put({.store = right_store, .id = message_id}));
+  graph.wait_for_all();
+  CHECK_FALSE(sink.try_get(output));
+
+  auto index_ports = join.index_ports();
+  REQUIRE(index_ports.size() == 2u);
+  REQUIRE(index_ports[0].index_port->try_put(
+    {.index = left_store->index(), .msg_id = message_id, .cache = true}));
+  graph.wait_for_all();
+  CHECK_FALSE(sink.try_get(output));
+
+  REQUIRE(index_ports[1].index_port->try_put(
+    {.index = right_store->index(), .msg_id = message_id, .cache = true}));
+  graph.wait_for_all();
+
+  REQUIRE(sink.try_get(output));
+  CHECK_FALSE(sink.try_get(output));
+
+  CHECK(std::get<0>(output).id == message_id);
+  CHECK(std::get<1>(output).id == message_id);
+  REQUIRE(std::get<0>(output).store);
+  REQUIRE(std::get<1>(output).store);
+  CHECK(std::get<0>(output).store->index() == left_store->index());
+  CHECK(std::get<1>(output).store->index() == right_store->index());
+
+  // Do what is necessary to have the tokens flushed, so that the test does not generate
+  // warnings.
+  REQUIRE(index_ports[0].token_port->try_put({.index = left_store->index(), .count = 1}));
+  REQUIRE(index_ports[1].token_port->try_put({.index = right_store->index(), .count = 1}));
+  graph.wait_for_all();
+}
diff --git a/test/transform_node_test.cpp b/test/transform_node_test.cpp
new file mode 100644
index 000000000..fff626ba6
--- /dev/null
+++ b/test/transform_node_test.cpp
@@ -0,0 +1,153 @@
+#include "phlex/core/declared_transform.hpp"
+#include "phlex/metaprogramming/delegate.hpp"
+#include "phlex/model/data_cell_index.hpp"
+#include "phlex/model/product_store.hpp"
+
+#include "catch2/catch_test_macros.hpp"
+#include "oneapi/tbb/flow_graph.h"
+
+#include <memory>
+#include <string>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+using namespace phlex;
+using namespace phlex::detail;
+using namespace phlex::experimental;
+
+namespace {
+  constexpr auto message_id = 42u;
+
+  struct input_type_1 {
+    int value;
+    auto operator<=>(input_type_1 const&) const = default;
+  };
+
+  struct input_type_2 {
+    int value;
+    auto operator<=>(input_type_2 const&) const = default;
+  };
+
+  struct output_type_1 {
+    int value;
+    auto operator<=>(output_type_1 const&) const = default;
+  };
+
+  struct output_type_2 {
+    std::string value;
+    auto operator<=>(output_type_2 const&) const = default;
+  };
+
+  output_type_1 double_value(input_type_1 const& input) { return {input.value * 2}; }
+
+  auto number_and_label(input_type_1 const& input)
+  {
+    return std::tuple{output_type_1{input.value}, output_type_2{std::to_string(input.value)}};
+  }
+
+  template <typename T>
+  product_specification spec(char const* creator, char const* suffix)
+  {
+    return {algorithm_name{creator}, identifier{suffix}, make_type_id<T>()};
+  }
+
+  template <typename T>
+  product_selector selector(char const* creator, char const* suffix)
+  {
+    return {.creator = creator, .layer = "job", .suffix = suffix, .type = make_type_id<T>()};
+  }
+
+  template <typename T>
+  product_store_ptr store_with_product(char const* creator, char const* suffix, T value)
+  {
+    auto store = product_store::base(creator);
+    store->add_product(spec<T>(creator, suffix), std::move(value));
+    return store;
+  }
+
+  template <typename F>
+  auto algorithm_bits_for(F function)
+  {
+    return algorithm_bits{std::shared_ptr<void_tag>{}, std::move(function)};
+  }
+}
+
+TEST_CASE("transform_node directly transforms one input product", "[transform_node]")
+{
+  oneapi::tbb::flow::graph graph;
+  auto input_selector = selector<input_type_1>("input", "");
+  auto input_store = store_with_product("input", "", input_type_1{21});
+  auto alg = algorithm_bits_for(double_value);
+
+  transform_node<decltype(alg)> node{
+    algorithm_name{"double_value"}, 1u, {}, graph, std::move(alg), {input_selector}, {}};
+  declared_transform& transform = node;
+
+  auto const& output_specs = transform.output();
+  REQUIRE(output_specs.size() == 1u);
+  CHECK(output_specs[0].creator() == algorithm_name{"double_value"});
+  CHECK(output_specs[0].suffix() == identifier{""});
+  CHECK(output_specs[0].type() == make_type_id<output_type_1>());
+
+  oneapi::tbb::flow::queue_node<message> sink{graph};
+  make_edge(transform.output_port(), sink);
+
+  REQUIRE(node.port(input_selector).try_put({.store = input_store, .id = message_id}));
+  graph.wait_for_all();
+
+  message output;
+  REQUIRE(sink.try_get(output));
+
+  CHECK(output.id == message_id);
+  REQUIRE(output.store);
+  CHECK(output.store->index() == input_store->index());
+  CHECK(output.store->source() == algorithm_name{"double_value"});
+  CHECK(output.store->get_product<output_type_1>(output_specs[0]) == output_type_1{42});
+
+  CHECK(transform.num_calls() == 1u);
+  CHECK(transform.product_count() == 1u);
+}
+
+TEST_CASE("transform_node stores multiple output products", "[transform_node]")
+{
+  oneapi::tbb::flow::graph graph;
+  auto input_selector = selector<input_type_1>("input", "");
+  auto input_store = store_with_product("input", "", input_type_1{7});
+  auto alg = algorithm_bits_for(number_and_label);
+
+  transform_node<decltype(alg)> node{algorithm_name{"number_and_label"},
+                                     1u,
+                                     {},
+                                     graph,
+                                     std::move(alg),
+                                     {input_selector},
+                                     {"number", "label"}};
+  declared_transform& transform = node;
+
+  oneapi::tbb::flow::queue_node<message> sink{graph};
+  make_edge(transform.output_port(), sink);
+
+  REQUIRE(node.port(input_selector).try_put({.store = input_store, .id = message_id}));
+  graph.wait_for_all();
+
+  message output;
+  REQUIRE(sink.try_get(output));
+  CHECK_FALSE(sink.try_get(output));
+
+  auto const& output_specs = transform.output();
+  REQUIRE(output_specs.size() == 2u);
+  CHECK(output_specs[0].creator() == algorithm_name{"number_and_label"});
+  CHECK(output_specs[0].suffix() == identifier{"number"});
+  CHECK(output_specs[0].type() == make_type_id<output_type_1>());
+  CHECK(output_specs[1].creator() == algorithm_name{"number_and_label"});
+  CHECK(output_specs[1].suffix() == identifier{"label"});
+  CHECK(output_specs[1].type() == make_type_id<output_type_2>());
+
+  REQUIRE(output.store);
+  CHECK(output.store->get_product<output_type_1>(output_specs[0]) == output_type_1{7});
+  CHECK(output.store->get_product<output_type_2>(output_specs[1]) == output_type_2{"7"});
+
+  CHECK(transform.num_calls() == 1u);
+  CHECK(transform.product_count() == 1u);
+}