diff --git a/src/utils/result.hpp b/src/utils/result.hpp
index 6293549..0af019c 100644
--- a/src/utils/result.hpp
+++ b/src/utils/result.hpp
@@ -60,19 +60,19 @@ namespace detail {
         }
 
         NODISCARD optional<T> value() const & {
-            return has_value() ? value_ : nullopt;
+            return has_value() ? optional<T>(value_) : nullopt;
         }
 
         NODISCARD optional<E> error() const & {
-            return is_error() ? error_ : nullopt;
+            return is_error() ? optional<E>(error_) : nullopt;
         }
 
         NODISCARD optional<T> value() && {
-            return has_value() ? std::move(value_) : nullopt;
+            return has_value() ? optional<T>(std::move(value_)) : nullopt;
         }
 
         NODISCARD optional<E> error() && {
-            return is_error() ? std::move(error_) : nullopt;
+            return is_error() ? optional<E>(std::move(error_)) : nullopt;
         }
 
         NODISCARD T& unwrap_value() & {
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 42e5a69..2642471 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -81,12 +81,14 @@ if(NOT CPPTRACE_SKIP_UNIT)
   add_executable(
     unittest
     unit/main.cpp
-    unit/raw_trace.cpp
-    unit/object_trace.cpp
-    unit/stacktrace.cpp
-    unit/from_current.cpp
-    unit/from_current_z.cpp
-    unit/traced_exception.cpp
+    unit/tracing/raw_trace.cpp
+    unit/tracing/object_trace.cpp
+    unit/tracing/stacktrace.cpp
+    unit/tracing/from_current.cpp
+    unit/tracing/from_current_z.cpp
+    unit/tracing/traced_exception.cpp
+    unit/internals/optional.cpp
+    unit/internals/result.cpp
   )
   target_compile_features(unittest PRIVATE cxx_std_20)
   target_link_libraries(unittest PRIVATE ${target_name} GTest::gtest_main GTest::gmock_main)
@@ -101,5 +103,6 @@ if(NOT CPPTRACE_SKIP_UNIT)
   if(CPPTRACE_SANITIZER_BUILD)
     target_compile_definitions(unittest PRIVATE CPPTRACE_SANITIZER_BUILD)
   endif()
+  target_include_directories(unittest PRIVATE ../src)
   add_test(NAME unittest COMMAND unittest)
 endif()
diff --git a/test/unit/internals/optional.cpp b/test/unit/internals/optional.cpp
new file mode 100644
index 0000000..f69d915
--- /dev/null
+++ b/test/unit/internals/optional.cpp
@@ -0,0 +1,119 @@
+#include <gtest/gtest.h>
+
+#include "utils/optional.hpp"
+
+using namespace cpptrace::detail;
+
+TEST(OptionalTest, DefaultConstructor) {
+    optional<int> o;
+    EXPECT_FALSE(o.has_value());
+    EXPECT_FALSE(static_cast<bool>(o));
+}
+
+TEST(OptionalTest, ConstructWithNullopt) {
+    optional<int> o(nullopt);
+    EXPECT_FALSE(o.has_value());
+}
+
+TEST(OptionalTest, ValueConstructor) {
+    optional<int> o(42);
+    EXPECT_TRUE(o.has_value());
+    EXPECT_EQ(o.unwrap(), 42);
+
+    int x = 100;
+    optional<int> o2(x);
+    EXPECT_TRUE(o2.has_value());
+    EXPECT_EQ(o2.unwrap(), 100);
+}
+
+TEST(OptionalTest, CopyConstructor) {
+    optional<int> o1(42);
+    optional<int> o2(o1);
+    EXPECT_TRUE(o2.has_value());
+    EXPECT_EQ(o2.unwrap(), 42);
+
+    optional<int> o3(nullopt);
+    optional<int> o4(o3);
+    EXPECT_FALSE(o4.has_value());
+}
+
+TEST(OptionalTest, MoveConstructor) {
+    optional<int> o1(42);
+    optional<int> o2(std::move(o1));
+    EXPECT_TRUE(o2.has_value());
+    EXPECT_EQ(o2.unwrap(), 42);
+
+    optional<int> o3(nullopt);
+    optional<int> o4(std::move(o3));
+    EXPECT_FALSE(o4.has_value());
+}
+
+TEST(OptionalTest, CopyAssignmentOperator) {
+    optional<int> o1(42);
+    optional<int> o2;
+    o2 = o1;
+    EXPECT_TRUE(o2.has_value());
+    EXPECT_EQ(o2.unwrap(), 42);
+
+    optional<int> o3(nullopt);
+    optional<int> o4(100);
+    o4 = o3;
+    EXPECT_FALSE(o4.has_value());
+}
+
+TEST(OptionalTest, MoveAssignmentOperator) {
+    optional<int> o1(42);
+    optional<int> o2;
+    o2 = std::move(o1);
+    EXPECT_TRUE(o2.has_value());
+    EXPECT_EQ(o2.unwrap(), 42);
+
+    optional<int> o3(nullopt);
+    optional<int> o4(99);
+    o4 = std::move(o3);
+    EXPECT_FALSE(o4.has_value());
+}
+
+TEST(OptionalTest, AssignmentFromValue) {
+    optional<int> o;
+    o = 123;
+    EXPECT_TRUE(o.has_value());
+    EXPECT_EQ(o.unwrap(), 123);
+
+    o = nullopt;
+    EXPECT_FALSE(o.has_value());
+}
+
+TEST(OptionalTest, Reset) {
+    optional<int> o(42);
+    EXPECT_TRUE(o.has_value());
+    o.reset();
+    EXPECT_FALSE(o.has_value());
+}
+
+TEST(OptionalTest, Swap) {
+    optional<int> o1(42);
+    optional<int> o2(100);
+
+    o1.swap(o2);
+    EXPECT_TRUE(o1.has_value());
+    EXPECT_TRUE(o2.has_value());
+    EXPECT_EQ(o1.unwrap(), 100);
+    EXPECT_EQ(o2.unwrap(), 42);
+
+    // Swap a value-holding optional with an empty optional
+    optional<int> o3(7);
+    optional<int> o4(nullopt);
+    o3.swap(o4);
+    EXPECT_FALSE(o3.has_value());
+    EXPECT_TRUE(o4.has_value());
+    EXPECT_EQ(o4.unwrap(), 7);
+}
+
+TEST(OptionalTest, ValueOr) {
+    optional<int> o1(42);
+    EXPECT_EQ(o1.value_or(100), 42);
+
+    optional<int> o2(nullopt);
+    EXPECT_EQ(o2.value_or(100), 100);
+}
diff --git a/test/unit/internals/result.cpp b/test/unit/internals/result.cpp
new file mode 100644
index 0000000..b942139
--- /dev/null
+++ b/test/unit/internals/result.cpp
@@ -0,0 +1,98 @@
+#include <gtest/gtest.h>
+
+#include "utils/result.hpp"
+
+using namespace cpptrace::detail;
+
+// A simple custom error type that behaves like a standard exception.
+struct error {
+    int x;
+    const char* what() const {
+        return "error...";
+    }
+};
+
+class ResultFixture : public testing::Test {
+public:
+    ResultFixture() {
+        cpptrace::absorb_trace_exceptions(true);
+    }
+
+    ~ResultFixture() override {
+        cpptrace::absorb_trace_exceptions(false);
+    }
+};
+
+TEST_F(ResultFixture, ConstructWithValueRValue) {
+    cpptrace::detail::Result<std::string, error> result("test");
+    EXPECT_TRUE(result.has_value());
+    EXPECT_FALSE(result.is_error());
+    EXPECT_TRUE(static_cast<bool>(result));
+
+    EXPECT_EQ(result.unwrap_value(), "test");
+    EXPECT_FALSE(result.error().has_value());
+}
+
+TEST_F(ResultFixture, ConstructWithValueLValue) {
+    std::string s = "test";
+    cpptrace::detail::Result<std::string, error> result(s);
+
+    EXPECT_TRUE(result.has_value());
+    EXPECT_FALSE(result.is_error());
+    EXPECT_EQ(result.unwrap_value(), "test");
+
+    s = "x";
+    EXPECT_EQ(result.unwrap_value(), "test");
+}
+
+TEST_F(ResultFixture, ConstructWithErrorRValue) {
+    cpptrace::detail::Result<std::string, error> result(error{1});
+    EXPECT_FALSE(result.has_value());
+    EXPECT_TRUE(result.is_error());
+    EXPECT_FALSE(static_cast<bool>(result));
+
+    EXPECT_EQ(result.unwrap_error().x, 1);
+
+    // Check that value() returns nullopt in this scenario
+    EXPECT_FALSE(result.value().has_value());
+}
+
+TEST_F(ResultFixture, ConstructWithErrorLValue) {
+    error e{1};
+    cpptrace::detail::Result<std::string, error> result(e);
+
+    EXPECT_FALSE(result.has_value());
+    EXPECT_TRUE(result.is_error());
+    EXPECT_EQ(result.unwrap_error().x, 1);
+}
+
+TEST_F(ResultFixture, MoveConstructorValue) {
+    cpptrace::detail::Result<std::string, error> original(std::string("move"));
+    cpptrace::detail::Result<std::string, error> moved(std::move(original));
+
+    EXPECT_TRUE(moved.has_value());
+    EXPECT_EQ(moved.unwrap_value(), "move");
+    EXPECT_TRUE(original.has_value());
+}
+
+TEST_F(ResultFixture, MoveConstructorError) {
+    cpptrace::detail::Result<std::string, error> original(error{1});
+    cpptrace::detail::Result<std::string, error> moved(std::move(original));
+
+    EXPECT_TRUE(moved.is_error());
+    EXPECT_EQ(moved.unwrap_error().x, 1);
+    EXPECT_TRUE(original.is_error());
+}
+
+TEST_F(ResultFixture, ValueOr) {
+    {
+        cpptrace::detail::Result<int, error> res_with_value(42);
+        EXPECT_EQ(res_with_value.value_or(-1), 42);
+        EXPECT_EQ(std::move(res_with_value).value_or(-1), 42);
+    }
+    {
+        cpptrace::detail::Result<int, error> res_with_error(error{});
+        EXPECT_EQ(res_with_error.value_or(-1), -1);
+        EXPECT_EQ(std::move(res_with_error).value_or(-1), -1);
+    }
+}
diff --git a/test/unit/from_current.cpp b/test/unit/tracing/from_current.cpp
similarity index 100%
rename from test/unit/from_current.cpp
rename to test/unit/tracing/from_current.cpp
diff --git a/test/unit/from_current_z.cpp b/test/unit/tracing/from_current_z.cpp
similarity index 100%
rename from test/unit/from_current_z.cpp
rename to test/unit/tracing/from_current_z.cpp
diff --git a/test/unit/object_trace.cpp b/test/unit/tracing/object_trace.cpp
similarity index 100%
rename from test/unit/object_trace.cpp
rename to test/unit/tracing/object_trace.cpp
diff --git a/test/unit/raw_trace.cpp b/test/unit/tracing/raw_trace.cpp
similarity index 100%
rename from test/unit/raw_trace.cpp
rename to test/unit/tracing/raw_trace.cpp
diff --git a/test/unit/stacktrace.cpp b/test/unit/tracing/stacktrace.cpp
similarity index 100%
rename from test/unit/stacktrace.cpp
rename to test/unit/tracing/stacktrace.cpp
diff --git a/test/unit/traced_exception.cpp b/test/unit/tracing/traced_exception.cpp
similarity index 100%
rename from test/unit/traced_exception.cpp
rename to test/unit/tracing/traced_exception.cpp