diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a3c3288..332eaa8 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,11 +1,20 @@
 include(ExternalProject)
-ExternalProject_Add(toml
-        SOURCE_DIR ${CMAKE_CURRENT_BINARY_DIR}/toml
-        GIT_REPOSITORY https://github.com/toml-lang/toml
-        GIT_TAG v0.5.0
+
+set(TOML11_LANGSPEC_GIT_REPOSITORY "https://github.com/toml-lang/toml" CACHE STRING
+    "URL of the TOML language specification repository")
+
+set(TOML11_LANGSPEC_SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}/toml" CACHE FILEPATH
+    "directory for the TOML language specification tree")
+
+if(NOT EXISTS "${TOML11_LANGSPEC_SOURCE_DIR}/toml.abnf")
+    ExternalProject_Add(toml
+        SOURCE_DIR "${TOML11_LANGSPEC_SOURCE_DIR}"
+        GIT_REPOSITORY "${TOML11_LANGSPEC_GIT_REPOSITORY}"
+        GIT_TAG "v0.5.0"
         CONFIGURE_COMMAND ""
         BUILD_COMMAND ""
         INSTALL_COMMAND "")
+endif()
 
 set(TEST_NAMES
     test_datetime
@@ -62,6 +71,82 @@ CHECK_CXX_COMPILER_FLAG("-Wrange-loop-analysis" COMPILER_SUPPORTS_WRANGE_LOOP_AN
 CHECK_CXX_COMPILER_FLAG("-Wundef"               COMPILER_SUPPORTS_WUNDEF)
 CHECK_CXX_COMPILER_FLAG("-Wshadow"              COMPILER_SUPPORTS_WSHADOW)
 
+include(CheckCXXSourceCompiles)
+
+# check which standard library implementation is used. If libstdc++ is used,
+# it will fail to compile. It compiles if libc++ is used.
+check_cxx_source_compiles("
+#include <cstddef>
+#ifdef __GLIBCXX__
+    static_assert(false);
+#endif
+int main() {
+    return 0;
+}" TOML11_WITH_LIBCXX_LIBRARY)
+
+# LLVM 8 requires -lc++fs if compiled with libc++ to use <filesystem>.
+# LLVM 9+ does not require any special library.
+# GCC 8 requires -lstdc++fs. GCC 9+ does not require it.
+#
+# Yes, we can check the version of the compiler used in the current build
+# directly in CMake. But, in most cases, clang build uses libstdc++ as the
+# standard library implementation and it makes the condition complicated.
+# In many environment, the default installed C++ compiler is GCC and libstdc++
+# is installed along with it. In most build on such an environment, even if we
+# chose clang as the C++ compiler, still libstdc++ is used. Checking default
+# gcc version makes the condition complicated.
+# The purpose of this file is to compile tests. We know the environment on which
+# the tests run. We can set this option and, I think, it is easier and better.
+option(TOML11_REQUIRE_FILESYSTEM_LIBRARY "need to link -lstdc++fs or -lc++fs" OFF)
+
+find_package(Boost COMPONENTS unit_test_framework REQUIRED)
+
+set(PREVIOUSLY_REQUIRED_INCLUDES "${CMAKE_REQUIRED_INCLUDES}")
+set(PREVIOUSLY_REQUIRED_LIBRARIES "${CMAKE_REQUIRED_LIBRARIES}")
+
+list(APPEND CMAKE_REQUIRED_INCLUDES ${Boost_INCLUDE_DIRS})
+list(APPEND CMAKE_REQUIRED_LIBRARIES ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY})
+
+check_cxx_source_compiles("
+#define BOOST_TEST_MODULE \"dummy\"
+#undef BOOST_TEST_DYN_LINK
+#define BOOST_TEST_NO_LIB
+#include <boost/test/included/unit_test.hpp>
+BOOST_AUTO_TEST_CASE(proforma) { BOOST_TEST(true); }
+" TOML11_WITH_BOOST_TEST_HEADER)
+
+check_cxx_source_compiles("
+#define BOOST_TEST_MODULE \"dummy\"
+#undef BOOST_TEST_DYN_LINK
+#undef BOOST_TEST_NO_LIB
+#include <boost/test/unit_test.hpp>
+BOOST_AUTO_TEST_CASE(proforma) { BOOST_TEST(true); }
+" TOML11_WITH_BOOST_TEST_STATIC)
+
+check_cxx_source_compiles("
+#define BOOST_TEST_MODULE \"dummy\"
+#define BOOST_TEST_DYN_LINK
+#undef BOOST_TEST_NO_LIB
+#include <boost/test/unit_test.hpp>
+BOOST_AUTO_TEST_CASE(proforma) { BOOST_TEST(true); }
+" TOML11_WITH_BOOST_TEST_DYNAMIC)
+
+set(CMAKE_REQUIRED_INCLUDES "${PREVIOUSLY_REQUIRED_INCLUDES}")
+set(CMAKE_REQUIRED_LIBRARIES "${PREVIOUSLY_REQUIRED_LIBRARIES}")
+
+unset(PREVIOUSLY_REQUIRED_INCLUDES)
+unset(PREVIOUSLY_REQUIRED_LIBRARIES)
+
+if(TOML11_WITH_BOOST_TEST_DYNAMIC)
+    add_definitions(-DUNITTEST_FRAMEWORK_LIBRARY_EXIST -DBOOST_TEST_DYN_LINK)
+elseif(TOML11_WITH_BOOST_TEST_STATIC)
+    add_definitions(-DUNITTEST_FRAMEWORK_LIBRARY_EXIST)
+elseif(TOML11_WITH_BOOST_TEST_HEADER)
+    add_definitions(-DBOOST_TEST_NO_LIB)
+else()
+    message(FATAL_ERROR "Neither the Boost.Test static or shared library nor the header-only version seem to be usable.")
+endif()
+
 if(COMPILER_SUPPORTS_WALL)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
 endif()
@@ -152,41 +237,18 @@ if(MSVC)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4265")
 endif()
 
-find_package(Boost COMPONENTS unit_test_framework REQUIRED)
-add_definitions(-DBOOST_TEST_DYN_LINK)
-add_definitions(-DUNITTEST_FRAMEWORK_LIBRARY_EXIST)
-
-# check which standard library implementation is used. If libstdc++ is used,
-# it will fail to compile. It compiles if libc++ is used.
-include(CheckCXXSourceCompiles)
-check_cxx_source_compiles("
-#include <cstddef>
-#ifdef __GLIBCXX__
-    static_assert(false);
-#endif
-int main() {
-    return 0;
-}" TOML11_WITH_LIBCXX_LIBRARY)
-
-# LLVM 8 requires -lc++fs if compiled with libc++ to use <filesystem>.
-# LLVM 9+ does not require any special library.
-# GCC 8 requires -lstdc++fs. GCC 9+ does not require it.
-#
-# Yes, we can check the version of the compiler used in the current build
-# directly in CMake. But, in most cases, clang build uses libstdc++ as the
-# standard library implementation and it makes the condition complicated.
-# In many environment, the default installed C++ compiler is GCC and libstdc++
-# is installed along with it. In most build on such an environment, even if we
-# chose clang as the C++ compiler, still libstdc++ is used. Checking default
-# gcc version makes the condition complicated.
-# The purpose of this file is to compile tests. We know the environment on which
-# the tests run. We can set this option and, I think, it is easier and better.
-option(TOML11_REQUIRE_FILESYSTEM_LIBRARY "need to link -lstdc++fs or -lc++fs" OFF)
+set(TEST_ENVIRON "TOMLDIR=${TOML11_LANGSPEC_SOURCE_DIR}")
+if(WIN32)
+    # Set the PATH to be able to find Boost DLL
+    STRING(REPLACE ";" "\\;" PATH_STRING "$ENV{PATH}")
+    list(APPEND TEST_ENVIRON "PATH=${PATH_STRING}\;${Boost_LIBRARY_DIRS}")
+endif()
 
 foreach(TEST_NAME ${TEST_NAMES})
     add_executable(${TEST_NAME} ${TEST_NAME}.cpp)
     target_link_libraries(${TEST_NAME} ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY} toml11::toml11)
     target_include_directories(${TEST_NAME} SYSTEM PRIVATE ${Boost_INCLUDE_DIRS})
+    target_compile_definitions(${TEST_NAME} PRIVATE "BOOST_TEST_MODULE=\"${TEST_NAME}\"")
 
     # to compile tests with <filesystem>...
     if(TOML11_REQUIRE_FILESYSTEM_LIBRARY)
@@ -212,14 +274,7 @@ foreach(TEST_NAME ${TEST_NAMES})
     endif()
 
     add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-
-    # Set the PATH to be able to find Boost DLL
-    if(WIN32)
-        STRING(REPLACE ";" "\\;" PATH_STRING "$ENV{PATH}")
-        set_tests_properties(${TEST_NAME}
-            PROPERTIES ENVIRONMENT "PATH=${PATH_STRING}\;${Boost_LIBRARY_DIRS}"
-        )
-    endif()
+    set_tests_properties(${TEST_NAME} PROPERTIES ENVIRONMENT "${TEST_ENVIRON}")
 endforeach(TEST_NAME)
 
 
diff --git a/tests/check.cpp b/tests/check.cpp
index a271f3f..bf67775 100644
--- a/tests/check.cpp
+++ b/tests/check.cpp
@@ -1,4 +1,5 @@
-#include "toml.hpp"
+#include <toml.hpp>
+
 #include <iostream>
 #include <iomanip>
 
diff --git a/tests/check_serialization.cpp b/tests/check_serialization.cpp
index 6f60103..e97d51b 100644
--- a/tests/check_serialization.cpp
+++ b/tests/check_serialization.cpp
@@ -1,6 +1,7 @@
-#include "toml.hpp"
-#include <iostream>
+#include <toml.hpp>
+
 #include <iomanip>
+#include <iostream>
 
 int main(int argc, char **argv)
 {
diff --git a/tests/check_toml_test.cpp b/tests/check_toml_test.cpp
index 9c57572..51404c9 100644
--- a/tests/check_toml_test.cpp
+++ b/tests/check_toml_test.cpp
@@ -1,6 +1,7 @@
-#include "toml.hpp"
-#include <iostream>
+#include <toml.hpp>
+
 #include <iomanip>
+#include <iostream>
 
 struct json_serializer
 {
diff --git a/tests/test_comments.cpp b/tests/test_comments.cpp
index 8cc6573..2d2b6a6 100644
--- a/tests/test_comments.cpp
+++ b/tests/test_comments.cpp
@@ -1,13 +1,7 @@
-#define BOOST_TEST_MODULE "test_comments"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-
 #include <toml.hpp>
 
+#include "unit_test.hpp"
+
 BOOST_AUTO_TEST_CASE(test_comment_before)
 {
     {
diff --git a/tests/test_datetime.cpp b/tests/test_datetime.cpp
index 395949e..bbbcc42 100644
--- a/tests/test_datetime.cpp
+++ b/tests/test_datetime.cpp
@@ -1,12 +1,7 @@
-#define BOOST_TEST_MODULE "test_datetime"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/datetime.hpp>
 
+#include "unit_test.hpp"
+
 BOOST_AUTO_TEST_CASE(test_local_date)
 {
     const toml::local_date date(2018, toml::month_t::Jan, 1);
diff --git a/tests/test_error_detection.cpp b/tests/test_error_detection.cpp
index 07c607f..5e39ef6 100644
--- a/tests/test_error_detection.cpp
+++ b/tests/test_error_detection.cpp
@@ -1,13 +1,9 @@
-#define BOOST_TEST_MODULE "test_error_detection"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <iostream>
+
+#include "unit_test.hpp"
+
 #include <fstream>
+#include <iostream>
 
 BOOST_AUTO_TEST_CASE(test_detect_empty_key)
 {
diff --git a/tests/test_expect.cpp b/tests/test_expect.cpp
index 2971f0c..308d4fb 100644
--- a/tests/test_expect.cpp
+++ b/tests/test_expect.cpp
@@ -1,16 +1,12 @@
-#define BOOST_TEST_MODULE "test_expect"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <array>
+#include <deque>
+#include <list>
 #include <map>
 #include <unordered_map>
-#include <list>
-#include <deque>
-#include <array>
 
 BOOST_AUTO_TEST_CASE(test_expect)
 {
diff --git a/tests/test_extended_conversions.cpp b/tests/test_extended_conversions.cpp
index 7e727ac..1b21264 100644
--- a/tests/test_extended_conversions.cpp
+++ b/tests/test_extended_conversions.cpp
@@ -1,11 +1,7 @@
-#define BOOST_TEST_MODULE "test_extended_conversions"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
+
+#include "unit_test.hpp"
+
 #include <deque>
 #include <map>
 
diff --git a/tests/test_find.cpp b/tests/test_find.cpp
index aa44b7b..944b8e8 100644
--- a/tests/test_find.cpp
+++ b/tests/test_find.cpp
@@ -1,22 +1,17 @@
-#define BOOST_TEST_MODULE "test_find"
-
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-
 #include <toml.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
+
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <list>
+#include <map>
+#include <tuple>
+#include <unordered_map>
+
 #if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
 #include <string_view>
 #endif
-#include <tuple>
 
 using test_value_types = std::tuple<
     toml::basic_value<toml::discard_comments>,
@@ -830,4 +825,3 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_offset_datetime, value_type, test_va
         BOOST_TEST(tm.tm_sec ==            0);
     }
 }
-
diff --git a/tests/test_find_or.cpp b/tests/test_find_or.cpp
index b0f786d..8348f2f 100644
--- a/tests/test_find_or.cpp
+++ b/tests/test_find_or.cpp
@@ -1,17 +1,14 @@
-#define BOOST_TEST_MODULE "test_find_or"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
+
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <list>
+#include <map>
 #include <tuple>
+#include <unordered_map>
+
 #if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
 #include <string_view>
 #endif
diff --git a/tests/test_find_or_recursive.cpp b/tests/test_find_or_recursive.cpp
index 364112a..1f2f480 100644
--- a/tests/test_find_or_recursive.cpp
+++ b/tests/test_find_or_recursive.cpp
@@ -1,17 +1,14 @@
-#define BOOST_TEST_MODULE "test_find_or_recursive"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
+
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <list>
+#include <map>
 #include <tuple>
+#include <unordered_map>
+
 #if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
 #include <string_view>
 #endif
@@ -394,8 +391,3 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_move_only, value_type, test_value_typ
         BOOST_TEST(ref == toml::find_or(v, "key1", "key2", std::move(opt)));
     }
 }
-
-
-
-
-
diff --git a/tests/test_format_error.cpp b/tests/test_format_error.cpp
index df558da..c00f845 100644
--- a/tests/test_format_error.cpp
+++ b/tests/test_format_error.cpp
@@ -1,11 +1,7 @@
-#define BOOST_TEST_MODULE "test_format_error"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
+
+#include "unit_test.hpp"
+
 #include <iostream>
 
 // to check it successfully compiles. it does not check the formatted string.
diff --git a/tests/test_get.cpp b/tests/test_get.cpp
index a0dd315..4a16e34 100644
--- a/tests/test_get.cpp
+++ b/tests/test_get.cpp
@@ -1,17 +1,14 @@
-#define BOOST_TEST_MODULE "test_get"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
+
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <list>
+#include <map>
 #include <tuple>
+#include <unordered_map>
+
 #if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
 #include <string_view>
 #endif
@@ -506,4 +503,3 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_offset_datetime, value_type, test_va
     BOOST_TEST(tm.tm_sec ==            0);
     }
 }
-
diff --git a/tests/test_get_or.cpp b/tests/test_get_or.cpp
index 081b966..9ecb36e 100644
--- a/tests/test_get_or.cpp
+++ b/tests/test_get_or.cpp
@@ -1,17 +1,14 @@
-#define BOOST_TEST_MODULE "test_get_or"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
+
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <list>
+#include <map>
 #include <tuple>
+#include <unordered_map>
+
 #if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
 #include <string_view>
 #endif
diff --git a/tests/test_lex_boolean.cpp b/tests/test_lex_boolean.cpp
index c2e43a8..deecffe 100644
--- a/tests/test_lex_boolean.cpp
+++ b/tests/test_lex_boolean.cpp
@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_boolean"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_lex_datetime.cpp b/tests/test_lex_datetime.cpp
index a790eeb..8e33d38 100644
--- a/tests/test_lex_datetime.cpp
+++ b/tests/test_lex_datetime.cpp
@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_datetime"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_lex_floating.cpp b/tests/test_lex_floating.cpp
index 9c5c809..8c9cd20 100644
--- a/tests/test_lex_floating.cpp
+++ b/tests/test_lex_floating.cpp
@@ -1,9 +1,10 @@
-#define BOOST_TEST_MODULE "test_lex_floating"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
-#include <limits>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
+#include <limits>
+
 using namespace toml;
 using namespace detail;
 
diff --git a/tests/test_lex_integer.cpp b/tests/test_lex_integer.cpp
index bb6dbb7..50b9178 100644
--- a/tests/test_lex_integer.cpp
+++ b/tests/test_lex_integer.cpp
@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_integer"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_lex_key_comment.cpp b/tests/test_lex_key_comment.cpp
index 0921bd6..da123a4 100644
--- a/tests/test_lex_key_comment.cpp
+++ b/tests/test_lex_key_comment.cpp
@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "lex_key_comment_test"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_lex_string.cpp b/tests/test_lex_string.cpp
index 643ab31..f8f2424 100644
--- a/tests/test_lex_string.cpp
+++ b/tests/test_lex_string.cpp
@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_string"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_literals.cpp b/tests/test_literals.cpp
index 5aaf928..de81f39 100644
--- a/tests/test_literals.cpp
+++ b/tests/test_literals.cpp
@@ -1,11 +1,7 @@
-#define BOOST_TEST_MODULE "test_literals"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
+
+#include "unit_test.hpp"
+
 #include <map>
 
 BOOST_AUTO_TEST_CASE(test_file_as_literal)
diff --git a/tests/test_parse_array.cpp b/tests/test_parse_array.cpp
index a75a6f1..053d4c5 100644
--- a/tests/test_parse_array.cpp
+++ b/tests/test_parse_array.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_array<toml::value>_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_boolean.cpp b/tests/test_parse_boolean.cpp
index 068aaa4..5ed128c 100644
--- a/tests/test_parse_boolean.cpp
+++ b/tests/test_parse_boolean.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "test_parse_boolean"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_datetime.cpp b/tests/test_parse_datetime.cpp
index e7247b0..46bd78c 100644
--- a/tests/test_parse_datetime.cpp
+++ b/tests/test_parse_datetime.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_datetime_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_file.cpp b/tests/test_parse_file.cpp
index b525f98..2c45670 100644
--- a/tests/test_parse_file.cpp
+++ b/tests/test_parse_file.cpp
@@ -1,19 +1,15 @@
-#define BOOST_TEST_MODULE "test_parse_file"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <iostream>
-#include <fstream>
-#include <map>
+
+#include "unit_test.hpp"
+
 #include <deque>
+#include <fstream>
+#include <iostream>
+#include <map>
 
 BOOST_AUTO_TEST_CASE(test_example)
 {
-    const auto data = toml::parse("toml/tests/example.toml");
+    const auto data = toml::parse(testinput("example.toml"));
 
     BOOST_TEST(toml::find<std::string>(data, "title") == "TOML Example");
     const auto& owner = toml::find(data, "owner");
@@ -76,7 +72,7 @@ BOOST_AUTO_TEST_CASE(test_example)
 
 BOOST_AUTO_TEST_CASE(test_example_stream)
 {
-    std::ifstream ifs("toml/tests/example.toml", std::ios::binary);
+    std::ifstream ifs(testinput("example.toml"), std::ios::binary);
     const auto data = toml::parse(ifs);
 
     BOOST_TEST(toml::find<std::string>(data, "title") == "TOML Example");
@@ -144,7 +140,7 @@ BOOST_AUTO_TEST_CASE(test_example_stream)
 
 BOOST_AUTO_TEST_CASE(test_example_file_pointer)
 {
-    FILE * file = fopen("toml/tests/example.toml", "rb");
+    FILE * file = fopen(testinput("example.toml").c_str(), "rb");
     const auto data = toml::parse(file, "toml/tests/example.toml");
     fclose(file);
 
@@ -213,7 +209,7 @@ BOOST_AUTO_TEST_CASE(test_example_file_pointer)
 
 BOOST_AUTO_TEST_CASE(test_fruit)
 {
-    const auto data = toml::parse("toml/tests/fruit.toml");
+    const auto data = toml::parse(testinput("fruit.toml"));
     const auto blah = toml::find<toml::array>(toml::find(data, "fruit"), "blah");
     BOOST_TEST(toml::find<std::string>(blah.at(0), "name") == "apple");
     BOOST_TEST(toml::find<std::string>(blah.at(1), "name") == "banana");
@@ -231,7 +227,7 @@ BOOST_AUTO_TEST_CASE(test_fruit)
 
 BOOST_AUTO_TEST_CASE(test_hard_example)
 {
-    const auto data = toml::parse("toml/tests/hard_example.toml");
+    const auto data = toml::parse(testinput("hard_example.toml"));
     const auto the = toml::find(data, "the");
     BOOST_TEST(toml::find<std::string>(the, "test_string") ==
                       "You'll hate me after this - #");
@@ -258,7 +254,7 @@ BOOST_AUTO_TEST_CASE(test_hard_example)
 }
 BOOST_AUTO_TEST_CASE(test_hard_example_comment)
 {
-    const auto data = toml::parse<toml::preserve_comments>("toml/tests/hard_example.toml");
+    const auto data = toml::parse<toml::preserve_comments>(testinput("hard_example.toml"));
     const auto the = toml::find(data, "the");
     BOOST_TEST(toml::find<std::string>(the, "test_string") ==
                       "You'll hate me after this - #");
@@ -287,7 +283,7 @@ BOOST_AUTO_TEST_CASE(test_hard_example_comment)
 
 BOOST_AUTO_TEST_CASE(test_example_preserve_comment)
 {
-    const auto data = toml::parse<toml::preserve_comments>("toml/tests/example.toml");
+    const auto data = toml::parse<toml::preserve_comments>(testinput("example.toml"));
 
     BOOST_TEST(toml::find<std::string>(data, "title") == "TOML Example");
     const auto& owner = toml::find(data, "owner");
@@ -369,8 +365,8 @@ BOOST_AUTO_TEST_CASE(test_example_preserve_comment)
 
 BOOST_AUTO_TEST_CASE(test_example_preserve_stdmap_stddeque)
 {
-    const auto data = toml::parse<toml::preserve_comments, std::map, std::deque
-          >("toml/tests/example.toml");
+    const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(
+            testinput("example.toml"));
 
     static_assert(std::is_same<typename decltype(data)::table_type,
             std::map<toml::key, typename std::remove_cv<decltype(data)>::type>
@@ -993,40 +989,18 @@ BOOST_AUTO_TEST_CASE(test_file_ends_without_lf)
 
 BOOST_AUTO_TEST_CASE(test_parse_function_compiles)
 {
-    // toml::parse("");
-    const auto string_literal = toml::parse("toml/tests/example.toml");
-
-    BOOST_TEST_MESSAGE("string_literal");
-
-    const char* fname_cstring = "toml/tests/example.toml";
-    // toml::parse(const char*);
-    const auto cstring = toml::parse(fname_cstring);
-
-    BOOST_TEST_MESSAGE("const char*");
-
-    // toml::parse(char*);
-    std::array<char, 24> fname_char_ptr;
-    std::strncpy(fname_char_ptr.data(), fname_cstring, 24);
-    const auto char_ptr = toml::parse(fname_char_ptr.data());
-
-    BOOST_TEST_MESSAGE("char*");
-
-    // toml::parse(const std::string&);
-    const std::string fname_string("toml/tests/example.toml");
-    const auto string = toml::parse(fname_string);
-    std::string fname_string_mut("toml/tests/example.toml");
-    // toml::parse(std::string&);
-    const auto string_mutref = toml::parse(fname_string_mut);
-    // toml::parse(std::string&&);
-    const auto string_rref = toml::parse(std::move(fname_string_mut));
-
-    BOOST_TEST_MESSAGE("strings");
-
+    using result_type = decltype(toml::parse("string literal"));
+    (void) [](const char* that) -> result_type { return toml::parse(that); };
+    (void) [](char* that) -> result_type { return toml::parse(that); };
+    (void) [](const std::string& that) -> result_type { return toml::parse(that); };
+    (void) [](std::string& that) -> result_type { return toml::parse(that); };
+    (void) [](std::string&& that) -> result_type { return toml::parse(that); };
 #ifdef TOML11_HAS_STD_FILESYSTEM
-    const std::filesystem::path fname_path(fname_string.begin(), fname_string.end());
-    const auto filesystem_path = toml::parse(fname_path);
-    BOOST_TEST_MESSAGE("path");
+    (void) [](const std::filesystem::path& that) -> result_type { return toml::parse(that); };
+    (void) [](std::filesystem::path& that) -> result_type { return toml::parse(that); };
+    (void) [](std::filesystem::path&& that) -> result_type { return toml::parse(that); };
 #endif
+    (void) [](std::FILE* that) -> result_type { return toml::parse(that, "mandatory.toml"); };
 }
 
 BOOST_AUTO_TEST_CASE(test_parse_nonexistent_file)
diff --git a/tests/test_parse_floating.cpp b/tests/test_parse_floating.cpp
index 15f433d..5c05bab 100644
--- a/tests/test_parse_floating.cpp
+++ b/tests/test_parse_floating.cpp
@@ -1,14 +1,10 @@
-#define BOOST_TEST_MODULE "parse_floating_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
-#include <cmath>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
+#include <cmath>
+
 using namespace toml;
 using namespace detail;
 
diff --git a/tests/test_parse_inline_table.cpp b/tests/test_parse_inline_table.cpp
index 5fa99c1..9217a23 100644
--- a/tests/test_parse_inline_table.cpp
+++ b/tests/test_parse_inline_table.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_inline_table_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_integer.cpp b/tests/test_parse_integer.cpp
index 8e73686..423961f 100644
--- a/tests/test_parse_integer.cpp
+++ b/tests/test_parse_integer.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_integer_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_key.cpp b/tests/test_parse_key.cpp
index f05c26b..3af0eaa 100644
--- a/tests/test_parse_key.cpp
+++ b/tests/test_parse_key.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_key_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_string.cpp b/tests/test_parse_string.cpp
index 5367c00..bf381e3 100644
--- a/tests/test_parse_string.cpp
+++ b/tests/test_parse_string.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_string_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_table.cpp b/tests/test_parse_table.cpp
index cb5baee..0fd54c7 100644
--- a/tests/test_parse_table.cpp
+++ b/tests/test_parse_table.cpp
@@ -1,12 +1,7 @@
-#define BOOST_TEST_MODULE "parse_table_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-#include <toml/parser.hpp>
 #include <toml/get.hpp>
+#include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_table_key.cpp b/tests/test_parse_table_key.cpp
index 47df434..a921c96 100644
--- a/tests/test_parse_table_key.cpp
+++ b/tests/test_parse_table_key.cpp
@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_table_key_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
diff --git a/tests/test_parse_unicode.cpp b/tests/test_parse_unicode.cpp
index e3797a6..8bc4253 100644
--- a/tests/test_parse_unicode.cpp
+++ b/tests/test_parse_unicode.cpp
@@ -1,17 +1,13 @@
-#define BOOST_TEST_MODULE "test_parse_unicode"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <iostream>
+
+#include "unit_test.hpp"
+
 #include <fstream>
+#include <iostream>
 
 BOOST_AUTO_TEST_CASE(test_hard_example_unicode)
 {
-    const auto data = toml::parse("toml/tests/hard_example_unicode.toml");
+    const auto data = toml::parse(testinput("hard_example_unicode.toml"));
 
     const auto the = toml::find<toml::table>(data, "the");
     BOOST_TEST(toml::get<std::string>(the.at("test_string")) ==
diff --git a/tests/test_result.cpp b/tests/test_result.cpp
index d693bd6..ad5084c 100644
--- a/tests/test_result.cpp
+++ b/tests/test_result.cpp
@@ -1,8 +1,9 @@
-#define BOOST_TEST_MODULE "test_result"
-#include <boost/test/unit_test.hpp>
-#include <iostream>
 #include <toml/result.hpp>
 
+#include "unit_test.hpp"
+
+#include <iostream>
+
 BOOST_AUTO_TEST_CASE(test_construct)
 {
     {
@@ -437,5 +438,3 @@ BOOST_AUTO_TEST_CASE(test_and_or_other)
         BOOST_TEST("foo" == r1_gen().and_other(r2_gen()).unwrap_err());
     }
 }
-
-
diff --git a/tests/test_serialize_file.cpp b/tests/test_serialize_file.cpp
index 7e1d8e1..b6b8acb 100644
--- a/tests/test_serialize_file.cpp
+++ b/tests/test_serialize_file.cpp
@@ -1,15 +1,11 @@
-#define BOOST_TEST_MODULE "test_serialize_file"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
+
+#include "unit_test.hpp"
+
 #include <deque>
-#include <map>
-#include <iostream>
 #include <fstream>
+#include <iostream>
+#include <map>
 #include <sstream>
 
 template<typename Comment,
@@ -47,7 +43,7 @@ bool has_comment_inside(const toml::basic_value<Comment, Table, Array>& v)
 
 BOOST_AUTO_TEST_CASE(test_example)
 {
-    const auto data = toml::parse("toml/tests/example.toml");
+    const auto data = toml::parse(testinput("example.toml"));
     {
         std::ofstream ofs("tmp1.toml");
         ofs << std::setw(80) << data;
@@ -69,7 +65,7 @@ BOOST_AUTO_TEST_CASE(test_example)
 BOOST_AUTO_TEST_CASE(test_example_map_dq)
 {
     const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
-            "toml/tests/example.toml");
+            testinput("example.toml"));
     {
         std::ofstream ofs("tmp1_map_dq.toml");
         ofs << std::setw(80) << data;
@@ -91,7 +87,7 @@ BOOST_AUTO_TEST_CASE(test_example_map_dq)
 
 BOOST_AUTO_TEST_CASE(test_example_with_comment)
 {
-    const auto data = toml::parse<toml::preserve_comments>("toml/tests/example.toml");
+    const auto data = toml::parse<toml::preserve_comments>(testinput("example.toml"));
     {
         std::ofstream ofs("tmp1_com.toml");
         ofs << std::setw(80) << data;
@@ -117,7 +113,7 @@ BOOST_AUTO_TEST_CASE(test_example_with_comment)
 BOOST_AUTO_TEST_CASE(test_example_with_comment_nocomment)
 {
     {
-        const auto data = toml::parse<toml::preserve_comments>("toml/tests/example.toml");
+        const auto data = toml::parse<toml::preserve_comments>(testinput("example.toml"));
         {
             std::ofstream ofs("tmp1_com_nocomment.toml");
             ofs << std::setw(80) << toml::nocomment << data;
@@ -127,7 +123,7 @@ BOOST_AUTO_TEST_CASE(test_example_with_comment_nocomment)
         BOOST_TEST(!has_comment_inside(serialized));
     }
     {
-        const auto data_nocomment = toml::parse<toml::discard_comments>("toml/tests/example.toml");
+        const auto data_nocomment = toml::parse<toml::discard_comments>(testinput("example.toml"));
         auto serialized = toml::parse<toml::discard_comments>("tmp1_com_nocomment.toml");
         {
             auto& owner = toml::find(serialized, "owner");
@@ -146,7 +142,7 @@ BOOST_AUTO_TEST_CASE(test_example_with_comment_nocomment)
 BOOST_AUTO_TEST_CASE(test_example_with_comment_map_dq)
 {
     const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(
-            "toml/tests/example.toml");
+            testinput("example.toml"));
     {
         std::ofstream ofs("tmp1_com_map_dq.toml");
         ofs << std::setw(80) << data;
@@ -173,7 +169,7 @@ BOOST_AUTO_TEST_CASE(test_example_with_comment_map_dq)
 BOOST_AUTO_TEST_CASE(test_example_with_comment_map_dq_nocomment)
 {
     {
-        const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>("toml/tests/example.toml");
+        const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(testinput("example.toml"));
         {
             std::ofstream ofs("tmp1_com_map_dq_nocomment.toml");
             ofs << std::setw(80) << toml::nocomment << data;
@@ -182,7 +178,7 @@ BOOST_AUTO_TEST_CASE(test_example_with_comment_map_dq_nocomment)
         BOOST_TEST(!has_comment_inside(serialized));
     }
     {
-        const auto data_nocomment = toml::parse<toml::discard_comments>("toml/tests/example.toml");
+        const auto data_nocomment = toml::parse<toml::discard_comments>(testinput("example.toml"));
         auto serialized = toml::parse<toml::discard_comments>("tmp1_com_map_dq_nocomment.toml");
         {
             auto& owner = toml::find(serialized, "owner");
@@ -199,7 +195,7 @@ BOOST_AUTO_TEST_CASE(test_example_with_comment_map_dq_nocomment)
 
 BOOST_AUTO_TEST_CASE(test_fruit)
 {
-    const auto data = toml::parse("toml/tests/fruit.toml");
+    const auto data = toml::parse(testinput("fruit.toml"));
     {
         std::ofstream ofs("tmp2.toml");
         ofs << std::setw(80) << data;
@@ -211,7 +207,7 @@ BOOST_AUTO_TEST_CASE(test_fruit)
 BOOST_AUTO_TEST_CASE(test_fruit_map_dq)
 {
     const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
-            "toml/tests/fruit.toml");
+            testinput("fruit.toml"));
     {
         std::ofstream ofs("tmp2.toml");
         ofs << std::setw(80) << data;
@@ -223,7 +219,7 @@ BOOST_AUTO_TEST_CASE(test_fruit_map_dq)
 
 BOOST_AUTO_TEST_CASE(test_fruit_with_comments)
 {
-    const auto data = toml::parse<toml::preserve_comments>("toml/tests/fruit.toml");
+    const auto data = toml::parse<toml::preserve_comments>(testinput("fruit.toml"));
     {
         std::ofstream ofs("tmp2_com.toml");
         ofs << std::setw(80) << data;
@@ -235,7 +231,7 @@ BOOST_AUTO_TEST_CASE(test_fruit_with_comments)
 BOOST_AUTO_TEST_CASE(test_fruit_with_comments_map_dq)
 {
     const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(
-        "toml/tests/fruit.toml");
+            testinput("fruit.toml"));
     {
         std::ofstream ofs("tmp2_com.toml");
         ofs << std::setw(80) << data;
@@ -246,7 +242,7 @@ BOOST_AUTO_TEST_CASE(test_fruit_with_comments_map_dq)
 
 BOOST_AUTO_TEST_CASE(test_hard_example)
 {
-    const auto data = toml::parse("toml/tests/hard_example.toml");
+    const auto data = toml::parse(testinput("hard_example.toml"));
     {
         std::ofstream ofs("tmp3.toml");
         ofs << std::setw(80) << data;
@@ -258,7 +254,7 @@ BOOST_AUTO_TEST_CASE(test_hard_example)
 BOOST_AUTO_TEST_CASE(test_hard_example_map_dq)
 {
     const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
-            "toml/tests/hard_example.toml");
+            testinput("hard_example.toml"));
     {
         std::ofstream ofs("tmp3.toml");
         ofs << std::setw(80) << data;
@@ -271,7 +267,7 @@ BOOST_AUTO_TEST_CASE(test_hard_example_map_dq)
 BOOST_AUTO_TEST_CASE(test_hard_example_with_comment)
 {
     const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(
-            "toml/tests/hard_example.toml");
+            testinput("hard_example.toml"));
     {
         std::ofstream ofs("tmp3_com.toml");
         ofs << std::setw(80) << data;
diff --git a/tests/test_string.cpp b/tests/test_string.cpp
index 444fc63..e3f093a 100644
--- a/tests/test_string.cpp
+++ b/tests/test_string.cpp
@@ -1,7 +1,7 @@
-#define BOOST_TEST_MODULE "test_string"
-#include <boost/test/unit_test.hpp>
 #include <toml.hpp>
 
+#include "unit_test.hpp"
+
 BOOST_AUTO_TEST_CASE(test_basic_string)
 {
     {
@@ -151,4 +151,3 @@ BOOST_AUTO_TEST_CASE(test_string_add_assign)
 
 
 }
-
diff --git a/tests/test_traits.cpp b/tests/test_traits.cpp
index 63b8a14..4d5e3e2 100644
--- a/tests/test_traits.cpp
+++ b/tests/test_traits.cpp
@@ -1,21 +1,16 @@
-#define BOOST_TEST_MODULE "test_traits"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/types.hpp>
 
-#include <list>
-#include <forward_list>
-#include <deque>
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <forward_list>
+#include <list>
 #include <map>
 #include <set>
+#include <string>
 #include <unordered_map>
 #include <unordered_set>
-#include <string>
 
 struct dummy_type{};
 
diff --git a/tests/test_utility.cpp b/tests/test_utility.cpp
index 6919399..c67e3b8 100644
--- a/tests/test_utility.cpp
+++ b/tests/test_utility.cpp
@@ -1,13 +1,9 @@
-#define BOOST_TEST_MODULE "test_acceptor"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/utility.hpp>
-#include <vector>
+
+#include "unit_test.hpp"
+
 #include <array>
+#include <vector>
 
 BOOST_AUTO_TEST_CASE(test_try_reserve)
 {
diff --git a/tests/test_value.cpp b/tests/test_value.cpp
index 099d502..296d343 100644
--- a/tests/test_value.cpp
+++ b/tests/test_value.cpp
@@ -1,11 +1,7 @@
-#define BOOST_TEST_MODULE "test_value"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
+
+#include "unit_test.hpp"
+
 #include <map>
 #include <list>
 
diff --git a/tests/unit_test.hpp b/tests/unit_test.hpp
new file mode 100644
index 0000000..5999f57
--- /dev/null
+++ b/tests/unit_test.hpp
@@ -0,0 +1,23 @@
+#ifndef BOOST_TEST_MODULE
+#    error "Please #define BOOST_TEST_MODULE before you #include <unit_test.hpp>"
+#endif
+
+#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
+#    include <boost/test/unit_test.hpp>
+#else
+#    include <boost/test/included/unit_test.hpp>
+#endif
+
+#include <cstdlib>
+#include <string>
+
+static inline auto testinput(const std::string& basename) -> std::string
+{
+    const auto this_or_that = [](const char *const s, const char *const t) { return s ? s : t; };
+    std::string directory = this_or_that(std::getenv("TOMLDIR"), "toml");
+    if (!directory.empty() && directory.back() != '/')
+    {
+        directory.push_back('/');
+    }
+    return directory.append("tests/").append(basename);
+}
diff --git a/toml/comments.hpp b/toml/comments.hpp
index ec25041..c0f66f3 100644
--- a/toml/comments.hpp
+++ b/toml/comments.hpp
@@ -425,14 +425,14 @@ struct discard_comments
     // empty, so accessing through operator[], front/back, data causes address
     // error.
 
-    reference       operator[](const size_type)       noexcept {return *data();}
-    const_reference operator[](const size_type) const noexcept {return *data();}
+    reference       operator[](const size_type)       noexcept {never_call("toml::discard_comment::operator[]");}
+    const_reference operator[](const size_type) const noexcept {never_call("toml::discard_comment::operator[]");}
     reference       at(const size_type)       {throw std::out_of_range("toml::discard_comment is always empty.");}
     const_reference at(const size_type) const {throw std::out_of_range("toml::discard_comment is always empty.");}
-    reference       front()       noexcept {return *data();}
-    const_reference front() const noexcept {return *data();}
-    reference       back()        noexcept {return *data();}
-    const_reference back()  const noexcept {return *data();}
+    reference       front()       noexcept {never_call("toml::discard_comment::front");}
+    const_reference front() const noexcept {never_call("toml::discard_comment::front");}
+    reference       back()        noexcept {never_call("toml::discard_comment::back");}
+    const_reference back()  const noexcept {never_call("toml::discard_comment::back");}
 
     pointer         data()        noexcept {return nullptr;}
     const_pointer   data()  const noexcept {return nullptr;}
@@ -450,6 +450,18 @@ struct discard_comments
     const_reverse_iterator rend()    const noexcept {return const_iterator{};}
     const_reverse_iterator crbegin() const noexcept {return const_iterator{};}
     const_reverse_iterator crend()   const noexcept {return const_iterator{};}
+
+  private:
+
+    [[noreturn]] static void never_call(const char *const this_function)
+    {
+#ifdef __has_builtin
+#  if __has_builtin(__builtin_unreachable)
+        __builtin_unreachable();
+#  endif
+#endif
+        throw std::logic_error{this_function};
+    }
 };
 
 inline bool operator==(const discard_comments&, const discard_comments&) noexcept {return true;}
diff --git a/toml/datetime.hpp b/toml/datetime.hpp
index 36db1e1..83d04ba 100644
--- a/toml/datetime.hpp
+++ b/toml/datetime.hpp
@@ -85,9 +85,9 @@ enum class month_t : std::uint8_t
 
 struct local_date
 {
-    std::int16_t year;   // A.D. (like, 2018)
-    std::uint8_t month;  // [0, 11]
-    std::uint8_t day;    // [1, 31]
+    std::int16_t year{};   // A.D. (like, 2018)
+    std::uint8_t month{};  // [0, 11]
+    std::uint8_t day{};    // [1, 31]
 
     local_date(int y, month_t m, int d)
         : year (static_cast<std::int16_t>(y)),
@@ -181,12 +181,12 @@ operator<<(std::basic_ostream<charT, traits>& os, const local_date& date)
 
 struct local_time
 {
-    std::uint8_t  hour;        // [0, 23]
-    std::uint8_t  minute;      // [0, 59]
-    std::uint8_t  second;      // [0, 60]
-    std::uint16_t millisecond; // [0, 999]
-    std::uint16_t microsecond; // [0, 999]
-    std::uint16_t nanosecond;  // [0, 999]
+    std::uint8_t  hour{};        // [0, 23]
+    std::uint8_t  minute{};      // [0, 59]
+    std::uint8_t  second{};      // [0, 60]
+    std::uint16_t millisecond{}; // [0, 999]
+    std::uint16_t microsecond{}; // [0, 999]
+    std::uint16_t nanosecond{};  // [0, 999]
 
     local_time(int h, int m, int s,
                int ms = 0, int us = 0, int ns = 0)
@@ -297,8 +297,8 @@ operator<<(std::basic_ostream<charT, traits>& os, const local_time& time)
 
 struct time_offset
 {
-    std::int8_t hour;   // [-12, 12]
-    std::int8_t minute; // [-59, 59]
+    std::int8_t hour{};   // [-12, 12]
+    std::int8_t minute{}; // [-59, 59]
 
     time_offset(int h, int m)
         : hour  (static_cast<std::int8_t>(h)),
@@ -364,8 +364,8 @@ operator<<(std::basic_ostream<charT, traits>& os, const time_offset& offset)
 
 struct local_datetime
 {
-    local_date date;
-    local_time time;
+    local_date date{};
+    local_time time{};
 
     local_datetime(local_date d, local_time t): date(d), time(t) {}
 
@@ -478,9 +478,9 @@ operator<<(std::basic_ostream<charT, traits>& os, const local_datetime& dt)
 
 struct offset_datetime
 {
-    local_date  date;
-    local_time  time;
-    time_offset offset;
+    local_date  date{};
+    local_time  time{};
+    time_offset offset{};
 
     offset_datetime(local_date d, local_time t, time_offset o)
         : date(d), time(t), offset(o)
diff --git a/toml/parser.hpp b/toml/parser.hpp
index 4d59f0a..590cb2a 100644
--- a/toml/parser.hpp
+++ b/toml/parser.hpp
@@ -2414,12 +2414,14 @@ parse(std::vector<char>& letters, const std::string& fname)
         }
     }
 
-    const auto data = detail::parse_toml_file<value_type>(loc);
-    if(!data)
+    if (auto data = detail::parse_toml_file<value_type>(loc))
     {
-        throw syntax_error(data.unwrap_err(), source_location(loc));
+        return std::move(data).unwrap();
+    }
+    else
+    {
+        throw syntax_error(std::move(data).unwrap_err(), source_location(loc));
     }
-    return data.unwrap();
 }
 
 } // detail
diff --git a/toml/region.hpp b/toml/region.hpp
index 2e01e51..8c4f2f1 100644
--- a/toml/region.hpp
+++ b/toml/region.hpp
@@ -227,8 +227,7 @@ struct region final : public region_base
     region& operator+=(const region& other)
     {
         // different regions cannot be concatenated
-        assert(this->begin() == other.begin() && this->end() == other.end() &&
-               this->last_   == other.first_);
+        assert(this->source_ == other.source_ && this->last_ == other.first_);
 
         this->last_ = other.last_;
         return *this;