Fixed test cases under MS Visual Studio

src/sequence_diagram/generators/plantuml/sequence_diagram_generator.cc

@@ -330,9 +330,9 @@ void generator::generate_participant(
         const auto &relative_to =
             std::filesystem::canonical(m_config.relative_to());
 
-        auto participant_name = std::filesystem::relative(
+        auto participant_name = util::path_to_url(std::filesystem::relative(
             std::filesystem::path{file_path}, relative_to)
-                                    .string();
+                                    .string());
 
         ostr << "participant \"" << render_name(participant_name) << "\" as "
              << fmt::format("C_{:022}", file_id);

src/sequence_diagram/visitor/translation_unit_visitor.cc

@@ -2079,9 +2079,9 @@ std::string translation_unit_visitor::make_lambda_name(
     const auto location = cls->getLocation();
     const auto file_line = source_manager().getSpellingLineNumber(location);
     const auto file_column = source_manager().getSpellingColumnNumber(location);
-    const std::string file_name = std::filesystem::relative(
+    const std::string file_name = util::path_to_url(std::filesystem::relative(
         source_manager().getFilename(location).str(), config().relative_to())
-                                      .string();
+                                      .string());
 
     if (context().caller_id() != 0 &&
         get_participant(context().caller_id()).has_value()) {

src/util/util.cc

@@ -307,8 +307,20 @@ std::string path_to_url(const std::filesystem::path &p)
 {
     std::vector<std::string> path_tokens;
     auto it = p.begin();
-    if (p.has_root_directory())
+    if (p.has_root_directory()) {
+#ifdef _MSC_VER
+        // On Windows convert the root path using its drive letter, e.g.:
+        //   C:\A\B\include.h -> /c/A/B/include.h
+        if(p.root_name().string().size() > 1) {
+            if(p.is_absolute()) {
+                path_tokens.push_back(std::string{
+                    std::tolower(p.root_name().string().at(0), std::locale())});
+            }
+            it++;
+        }
+#endif
         it++;
+    }
 
     for (; it != p.end(); it++)
         path_tokens.push_back(it->string());