diff --git a/include/continuable/continuable-testing.hpp b/include/continuable/continuable-testing.hpp
index 7ca501f..4dcaebf 100644
--- a/include/continuable/continuable-testing.hpp
+++ b/include/continuable/continuable-testing.hpp
@@ -42,6 +42,13 @@
 #define ASSERT_ASYNC_COMPLETION(CONTINUABLE)                                   \
   cti::detail::testing::assert_async_completion(CONTINUABLE);
 
+/// Asserts that the final callback of the given continuable was called
+/// with any exceptional result.
+///
+/// \since version 2.0.0
+#define ASSERT_ASYNC_EXCEPTION_COMPLETION(CONTINUABLE)                         \
+  cti::detail::testing::assert_async_exception_completion(CONTINUABLE);
+
 /// Asserts that the final callback of the given continuable is never called
 /// with any result.
 ///
@@ -85,6 +92,18 @@
 #define ASSERT_ASYNC_BINARY_VALIDATION(VALIDATOR, ...)                         \
   cti::detail::testing::assert_async_binary_validation(VALIDATOR, __VA_ARGS__);
 
+/// Asserts that the continuation was resolved through an error and forwards
+/// it's error result to the given validator which can then do assertions on the
+/// error result.
+///
+/// \note This macro is mainly present for building other assertions
+///       relying on custom validation logic.
+///
+/// \since version 2.0.0
+#define ASSERT_ASYNC_BINARY_EXCEPTION_VALIDATION(VALIDATOR, ...)               \
+  cti::detail::testing::assert_async_binary_exception_validation(VALIDATOR,    \
+                                                                 __VA_ARGS__);
+
 /// Expects that the continuable is finished with the given result
 ///
 /// ```cpp
@@ -99,6 +118,13 @@
   ASSERT_ASYNC_BINARY_VALIDATION(cti::detail::testing::expecting_eq_check(),   \
                                  __VA_ARGS__)
 
+/// Asserts that the continuable is finished with the given exception
+///
+/// \since version 2.0.0
+#define EXPECT_ASYNC_EXCEPTION_RESULT(...)                                     \
+  ASSERT_ASYNC_BINARY_EXCEPTION_VALIDATION(                                    \
+      cti::detail::testing::expecting_eq_check(), __VA_ARGS__)
+
 /// Asserts that the continuable is finished with the given result
 ///
 /// ```cpp
@@ -130,11 +156,11 @@
   cti::detail::testing::assert_async_types(                                    \
       CONTINUABLE, cti::detail::traits::identity<__VA_ARGS__>{})
 
-/// Asserts that the continuable is finished with the given error
-/// TODO
+/// Asserts that the continuable is finished with the given exception
+///
 /// \since version 2.0.0
-#define ASSERT_ASYNC_ERROR(...)                                               \
-  ASSERT_ASYNC_BINARY_VALIDATION(cti::detail::testing::asserting_eq_check(),   \
-                                 __VA_ARGS__)
+#define ASSERT_ASYNC_EXCEPTION_RESULT(...)                                     \
+  ASSERT_ASYNC_BINARY_EXCEPTION_VALIDATION(                                    \
+      cti::detail::testing::asserting_eq_check(), __VA_ARGS__)
 
 #endif // CONTINUABLE_TESTING_HPP_INCLUDED__
diff --git a/include/continuable/detail/testing.hpp b/include/continuable/detail/testing.hpp
index c0f21aa..d504aad 100644
--- a/include/continuable/detail/testing.hpp
+++ b/include/continuable/detail/testing.hpp
@@ -31,9 +31,15 @@
 #ifndef CONTINUABLE_DETAIL_TESTING_HPP_INCLUDED__
 #define CONTINUABLE_DETAIL_TESTING_HPP_INCLUDED__
 
+#include <type_traits>
+#include <utility>
+
 #include <gtest/gtest.h>
 
-#include <continuable/continuable-base.hpp>
+#include <continuable/detail/api.hpp>
+#include <continuable/detail/traits.hpp>
+#include <continuable/detail/types.hpp>
+#include <continuable/detail/util.hpp>
 
 namespace cti {
 namespace detail {
@@ -41,25 +47,54 @@ namespace testing {
 template <typename C>
 void assert_async_completion(C&& continuable) {
   auto called = std::make_shared<bool>(false);
-  std::forward<C>(continuable).then([called](auto&&... args) {
-    ASSERT_FALSE(*called);
-    *called = true;
+  std::forward<C>(continuable)
+      .then([called](auto&&... args) {
+        ASSERT_FALSE(*called);
+        *called = true;
 
-    // Workaround for our known GCC bug.
-    util::unused(std::forward<decltype(args)>(args)...);
-  });
+        // Workaround for our known GCC bug.
+        util::unused(std::forward<decltype(args)>(args)...);
+      })
+      .fail([](cti::error_type /*error*/) {
+        // ...
+        FAIL();
+      });
+
+  ASSERT_TRUE(*called);
+}
+
+template <typename C>
+void assert_async_exception_completion(C&& continuable) {
+  auto called = std::make_shared<bool>(false);
+  std::forward<C>(continuable)
+      .then([](auto&&... args) {
+        // Workaround for our known GCC bug.
+        util::unused(std::forward<decltype(args)>(args)...);
+
+        // ...
+        FAIL();
+      })
+      .fail([called](cti::error_type /*error*/) {
+        ASSERT_FALSE(*called);
+        *called = true;
+      });
 
   ASSERT_TRUE(*called);
 }
 
 template <typename C>
 void assert_async_never_completed(C&& continuable) {
-  std::forward<C>(continuable).then([](auto&&... args) {
-    // Workaround for our known GCC bug.
-    util::unused(std::forward<decltype(args)>(args)...);
+  std::forward<C>(continuable)
+      .then([](auto&&... args) {
+        // Workaround for our known GCC bug.
+        util::unused(std::forward<decltype(args)>(args)...);
 
-    FAIL();
-  });
+        FAIL();
+      })
+      .fail([](cti::error_type /*error*/) {
+        // ...
+        FAIL();
+      });
 }
 
 template <typename C, typename V>
@@ -94,6 +129,43 @@ void assert_async_binary_validation(V&& validator, C&& continuable,
   });
 }
 
+/// Expects that the continuable is finished with the given arguments
+template <typename V, typename C, typename Args>
+void assert_async_binary_exception_validation(V&& validator, C&& continuable,
+                                              Args&& expected) {
+  auto called = std::make_shared<bool>(false);
+  std::forward<C>(continuable)
+      .then([](auto&&... args) {
+        // Workaround for our known GCC bug.
+        util::unused(std::forward<decltype(args)>(args)...);
+
+        // ...
+        FAIL();
+      })
+      .fail([
+        called, validator = std::forward<decltype(validator)>(validator),
+        expected = std::forward<decltype(expected)>(expected)
+      ](types::error_type error) {
+        ASSERT_FALSE(*called);
+        *called = true;
+
+#if !defined(CONTINUABLE_WITH_CUSTOM_ERROR_TYPE) &&                            \
+    !defined(CONTINUABLE_WITH_NO_EXCEPTIONS)
+        try {
+          std::rethrow_exception(error);
+        } catch (std::decay_t<decltype(expected)> const& exception) {
+          validator(exception, expected);
+        } catch (...) {
+          FAIL();
+        }
+#else
+        validator(error, expected);
+#endif
+      });
+
+  ASSERT_TRUE(*called);
+}
+
 inline auto expecting_eq_check() {
   return [](auto&& expected, auto&& actual) {
     EXPECT_EQ(std::forward<decltype(expected)>(expected),
diff --git a/include/continuable/detail/traits.hpp b/include/continuable/detail/traits.hpp
index 99674c3..8ac134b 100644
--- a/include/continuable/detail/traits.hpp
+++ b/include/continuable/detail/traits.hpp
@@ -32,6 +32,7 @@
 #define CONTINUABLE_DETAIL_TRAITS_HPP_INCLUDED__
 
 #include <cstdint>
+#include <initializer_list>
 #include <tuple>
 #include <type_traits>
 #include <utility>
@@ -347,8 +348,8 @@ constexpr void static_for_each_in(Sequenceable&& sequenceable,
   unpack(
       std::forward<Sequenceable>(sequenceable), [&](auto&&... entries) mutable {
         // Apply the consume function to every entry inside the pack
-        (void)std::initializer_list<int>{0,
-               ((void)handler(std::forward<decltype(entries)>(entries)), 0)...};
+        (void)std::initializer_list<int>{
+            0, ((void)handler(std::forward<decltype(entries)>(entries)), 0)...};
       });
 }
 
diff --git a/include/continuable/detail/util.hpp b/include/continuable/detail/util.hpp
index 2c701f9..7754630 100644
--- a/include/continuable/detail/util.hpp
+++ b/include/continuable/detail/util.hpp
@@ -31,6 +31,7 @@
 #ifndef CONTINUABLE_DETAIL_UTIL_HPP_INCLUDED__
 #define CONTINUABLE_DETAIL_UTIL_HPP_INCLUDED__
 
+#include <cassert>
 #include <tuple>
 #include <type_traits>
 #include <utility>
@@ -45,14 +46,7 @@ namespace detail {
 namespace util {
 /// Helper to trick compilers about that a parameter pack is used
 template <typename... T>
-void unused(T&&... args) {
-  auto use = [](auto&& type) mutable {
-    (void)type;
-    return 0;
-  };
-  auto deduce = {0, use(std::forward<decltype(args)>(args))...};
-  (void)deduce;
-  (void)use;
+void unused(T&&...) {
 }
 
 namespace detail {
diff --git a/test/unit-test/test-continuable-base-errors.cpp b/test/unit-test/test-continuable-base-errors.cpp
index 62a4f4f..70659e0 100644
--- a/test/unit-test/test-continuable-base-errors.cpp
+++ b/test/unit-test/test-continuable-base-errors.cpp
@@ -21,10 +21,53 @@
   SOFTWARE.
 **/
 
+#include <string>
+
+#include <continuable/detail/features.hpp>
+
 #include "test-continuable.hpp"
 
-TYPED_TEST(single_dimension_tests, are_using_errors) {
-  /*ASSERT_ASYNC_ERROR(this->supply().then([] {
-    return; // void
-  }));*/
+#if !defined(CONTINUABLE_WITH_NO_EXCEPTIONS)
+struct test_exception : std::exception {
+  explicit test_exception() {
+  }
+
+  bool operator==(test_exception const&) const noexcept {
+    return true;
+  }
+};
+
+static auto get_test_exception_proto() {
+  return test_exception{};
+}
+
+static auto supply_test_exception() {
+  try {
+    throw get_test_exception_proto();
+  } catch (...) {
+    return std::current_exception();
+  }
+}
+#else
+struct my_error_category : std::error_category {
+  const char* name() const override noexcept {return "generic name"}
+
+  std::string message(int) const override {
+    return "generic"
+  }
+};
+
+static auto get_test_exception_proto() {
+  static const my_error_category cat;
+  return std::error_condition(123, cat);
+}
+
+static auto supply_test_exception() {
+  return get_test_exception_proto();
+}
+#endif
+
+TYPED_TEST(single_dimension_tests, are_using_errors) {
+  ASSERT_ASYNC_EXCEPTION_COMPLETION(
+      this->supply_exception(supply_test_exception()));
 }
diff --git a/test/unit-test/test-continuable.hpp b/test/unit-test/test-continuable.hpp
index 6c635fe..fc06e03 100644
--- a/test/unit-test/test-continuable.hpp
+++ b/test/unit-test/test-continuable.hpp
@@ -24,57 +24,15 @@
 #ifndef TEST_CONTINUABLE_HPP__
 #define TEST_CONTINUABLE_HPP__
 
-#if UNIT_TEST_STEP >= 3
-#define THIRD_PARTY_TESTS
-#endif
-
-#ifdef THIRD_PARTY_TESTS
-// #if _MSC_VER
-// #pragma warning(push, 0)
-// #endif
-#endif // THIRD_PARTY_TESTS
-
 #include <cassert>
 
-#include "continuable/continuable-base.hpp"
-#include "continuable/continuable-testing.hpp"
-#include "continuable/continuable.hpp"
-#include "gtest/gtest.h"
+#include <gtest/gtest.h>
+
 #include <functional>
 
-#ifdef THIRD_PARTY_TESTS
-
-#include "cxx_function/cxx_function.hpp"
-
-template <typename T>
-using cxx_function_fn = cxx_function::function<T>;
-
-template <typename... Args>
-using cxx_trait_of =
-    cti::continuable_trait<cxx_function_fn, cxx_function_fn, Args...>;
-
-template <typename... Args>
-using cxx_continuable = typename cxx_trait_of<Args...>::continuable;
-
-template <typename T>
-using cxx_function_unique_fn = cxx_function::unique_function<T>;
-
-template <typename... Args>
-using unique_cxx_trait_of =
-    cti::continuable_trait<cxx_function_unique_fn, cxx_function_unique_fn,
-                           Args...>;
-
-template <typename... Args>
-using cxx_unique_continuable =
-    typename unique_cxx_trait_of<Args...>::continuable;
-#endif // THIRD_PARTY_TESTS
-
-template <typename... Args>
-using std_trait_of =
-    cti::continuable_trait<std::function, std::function, Args...>;
-
-template <typename... Args>
-using std_continuable = typename std_trait_of<Args...>::continuable;
+#include <continuable/continuable-base.hpp>
+#include <continuable/continuable-testing.hpp>
+#include <continuable/continuable.hpp>
 
 using cti::detail::traits::identity;
 
@@ -96,6 +54,13 @@ auto supplier_of(Args&&... args) {
   };
 }
 
+template <typename Arg>
+auto exception_supplier_of(Arg&& arg) {
+  return [arg = std::forward<Arg>(arg)](auto&& promise) mutable {
+    promise.set_exception(std::move(arg));
+  };
+}
+
 template <typename Provider>
 class continuation_provider : public ::testing::Test, public Provider {
 public:
@@ -115,6 +80,15 @@ public:
     return this->make(arg_types, hint_types,
                       supplier_of(std::forward<Args>(args)...));
   }
+
+  template <typename Arg>
+  auto supply_exception(Arg&& arg) {
+    identity<> arg_types;
+    auto hint_types = to_hint(arg_types);
+
+    return this->make(arg_types, hint_types,
+                      exception_supplier_of(std::forward<Arg>(arg)));
+  }
 };
 
 inline auto empty_caller() {