diff --git a/tests/t40001/.clang-uml b/tests/t40001/.clang-uml
index eee88bce..14660735 100644
--- a/tests/t40001/.clang-uml
+++ b/tests/t40001/.clang-uml
@@ -22,6 +22,8 @@ diagrams:
         - 'note right of {{ alias("include/lib1") }}: This is a lib1 include dir'
         - 'note right of {{ alias("include/t40001_include1.h") }}: This is a t40001_include1.h include file'
     mermaid:
+      before:
+        - "%% t40001 test diagram of type {{ diagram.type }}"
       after:
         - 'N_00001(This is a lib1 include dir)-.-{{ alias("include/lib1") }}'
-        - 'N_00002(This is a lib1 include dir)-.-{{ alias("include/t40001_include1.h") }}'
\ No newline at end of file
+        - 'N_00002(This is a t40001_include1.h include file)-.-{{ alias("include/t40001_include1.h") }}'
\ No newline at end of file
diff --git a/tests/t40001/test_case.h b/tests/t40001/test_case.h
index 3905c6f9..545c8cd2 100644
--- a/tests/t40001/test_case.h
+++ b/tests/t40001/test_case.h
@@ -29,31 +29,30 @@ TEST_CASE("t40001", "[test-case][include]")
     REQUIRE(model->name() == "t40001_include");
 
     {
-        auto puml = generate_include_puml(diagram, *model);
+        auto src = generate_include_puml(diagram, *model);
 
-        AliasMatcher _A(puml);
+        AliasMatcher _A(src);
 
-        REQUIRE_THAT(puml, StartsWith("@startuml"));
-        REQUIRE_THAT(puml, EndsWith("@enduml\n"));
+        REQUIRE_THAT(src, StartsWith("@startuml"));
+        REQUIRE_THAT(src, EndsWith("@enduml\n"));
 
-        REQUIRE_THAT(puml, IsFolder("lib1"));
-        REQUIRE_THAT(puml, IsFile("lib1.h"));
-        REQUIRE_THAT(puml, IsFile("t40001.cc"));
-        REQUIRE_THAT(puml, IsFile("t40001_include1.h"));
+        REQUIRE_THAT(src, IsFolder("lib1"));
+        REQUIRE_THAT(src, IsFile("lib1.h"));
+        REQUIRE_THAT(src, IsFile("t40001.cc"));
+        REQUIRE_THAT(src, IsFile("t40001_include1.h"));
 
-        REQUIRE_THAT(puml, IsFile("string"));
-        REQUIRE_THAT(puml, IsFile("yaml-cpp/yaml.h"));
+        REQUIRE_THAT(src, IsFile("string"));
+        REQUIRE_THAT(src, IsFile("yaml-cpp/yaml.h"));
 
         REQUIRE_THAT(
-            puml, IsAssociation(_A("t40001.cc"), _A("t40001_include1.h")));
-        REQUIRE_THAT(
-            puml, IsAssociation(_A("t40001_include1.h"), _A("lib1.h")));
+            src, IsAssociation(_A("t40001.cc"), _A("t40001_include1.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("t40001_include1.h"), _A("lib1.h")));
 
-        REQUIRE_THAT(puml, IsDependency(_A("t40001_include1.h"), _A("string")));
+        REQUIRE_THAT(src, IsDependency(_A("t40001_include1.h"), _A("string")));
 
-        REQUIRE_THAT(puml, HasComment("t40001 test diagram of type include"));
+        REQUIRE_THAT(src, HasComment("t40001 test diagram of type include"));
 
-        save_puml(config.output_directory(), diagram->name + ".puml", puml);
+        save_puml(config.output_directory(), diagram->name + ".puml", src);
     }
 
     {
@@ -81,8 +80,31 @@ TEST_CASE("t40001", "[test-case][include]")
     }
 
     {
-        auto mmd = generate_include_mermaid(diagram, *model);
+        auto src = generate_include_mermaid(diagram, *model);
 
-        save_mermaid(config.output_directory(), diagram->name + ".mmd", mmd);
+        mermaid::AliasMatcher _A(src);
+        using mermaid::HasComment;
+        using mermaid::IsFile;
+        using mermaid::IsFolder;
+        using mermaid::IsIncludeDependency;
+
+        REQUIRE_THAT(src, IsFolder(_A("lib1")));
+        REQUIRE_THAT(src, IsFile(_A("lib1.h")));
+        REQUIRE_THAT(src, IsFile(_A("t40001.cc")));
+        REQUIRE_THAT(src, IsFile(_A("t40001_include1.h")));
+
+        REQUIRE_THAT(src, IsFile(_A("string")));
+        REQUIRE_THAT(src, IsFile(_A("yaml-cpp/yaml.h")));
+
+        REQUIRE_THAT(
+            src, IsAssociation(_A("t40001.cc"), _A("t40001_include1.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("t40001_include1.h"), _A("lib1.h")));
+
+        REQUIRE_THAT(
+            src, IsIncludeDependency(_A("t40001_include1.h"), _A("string")));
+
+        REQUIRE_THAT(src, HasComment("t40001 test diagram of type include"));
+
+        save_mermaid(config.output_directory(), diagram->name + ".mmd", src);
     }
 }
diff --git a/tests/t40002/test_case.h b/tests/t40002/test_case.h
index 7f70d770..5a6e451c 100644
--- a/tests/t40002/test_case.h
+++ b/tests/t40002/test_case.h
@@ -29,58 +29,58 @@ TEST_CASE("t40002", "[test-case][include]")
     REQUIRE(model->name() == "t40002_include");
 
     {
-        auto puml = generate_include_puml(diagram, *model);
+        auto src = generate_include_puml(diagram, *model);
 
-        AliasMatcher _A(puml);
+        AliasMatcher _A(src);
 
-        REQUIRE_THAT(puml, StartsWith("@startuml"));
-        REQUIRE_THAT(puml, EndsWith("@enduml\n"));
+        REQUIRE_THAT(src, StartsWith("@startuml"));
+        REQUIRE_THAT(src, EndsWith("@enduml\n"));
 
-        REQUIRE_THAT(puml, IsFolder("lib1"));
-        REQUIRE_THAT(puml, IsFolder("lib2"));
-        REQUIRE_THAT(puml, IsFile("lib1.h"));
-        REQUIRE_THAT(puml, IsFile("lib2.h"));
-        REQUIRE_THAT(puml, !IsFile("lib2_detail.h"));
-        REQUIRE_THAT(puml, IsFile("t40002.cc"));
-        REQUIRE_THAT(puml, IsFile("lib1.cc"));
-        REQUIRE_THAT(puml, IsFile("lib2.cc"));
+        REQUIRE_THAT(src, IsFolder("lib1"));
+        REQUIRE_THAT(src, IsFolder("lib2"));
+        REQUIRE_THAT(src, IsFile("lib1.h"));
+        REQUIRE_THAT(src, IsFile("lib2.h"));
+        REQUIRE_THAT(src, !IsFile("lib2_detail.h"));
+        REQUIRE_THAT(src, IsFile("t40002.cc"));
+        REQUIRE_THAT(src, IsFile("lib1.cc"));
+        REQUIRE_THAT(src, IsFile("lib2.cc"));
 
-        REQUIRE_THAT(puml, !IsFile("string"));
+        REQUIRE_THAT(src, !IsFile("string"));
 
-        REQUIRE_THAT(puml, IsAssociation(_A("t40002.cc"), _A("lib1.h")));
-        REQUIRE_THAT(puml, IsAssociation(_A("lib1.h"), _A("lib2.h")));
-        REQUIRE_THAT(puml, IsAssociation(_A("lib1.cc"), _A("lib1.h")));
-        REQUIRE_THAT(puml, IsAssociation(_A("lib2.cc"), _A("lib2.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("t40002.cc"), _A("lib1.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("lib1.h"), _A("lib2.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("lib1.cc"), _A("lib1.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("lib2.cc"), _A("lib2.h")));
 
-        REQUIRE_THAT(puml,
+        REQUIRE_THAT(src,
             HasLink(_A("t40002.cc"),
                 fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
                             "t40002/src/t40002.cc#L0",
                     clanguml::util::get_git_commit()),
                 "t40002.cc"));
 
-        REQUIRE_THAT(puml,
+        REQUIRE_THAT(src,
             HasLink(_A("lib1.cc"),
                 fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
                             "t40002/src/lib1/lib1.cc#L0",
                     clanguml::util::get_git_commit()),
                 "lib1.cc"));
 
-        REQUIRE_THAT(puml,
+        REQUIRE_THAT(src,
             HasLink(_A("lib1.h"),
                 fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
                             "t40002/include/lib1/lib1.h#L0",
                     clanguml::util::get_git_commit()),
                 "lib1.h"));
 
-        REQUIRE_THAT(puml,
+        REQUIRE_THAT(src,
             HasLink(_A("lib2.h"),
                 fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
                             "t40002/include/lib2/lib2.h#L0",
                     clanguml::util::get_git_commit()),
                 "lib2.h"));
 
-        save_puml(config.output_directory(), diagram->name + ".puml", puml);
+        save_puml(config.output_directory(), diagram->name + ".puml", src);
     }
 
     {
@@ -112,8 +112,57 @@ TEST_CASE("t40002", "[test-case][include]")
     }
 
     {
-        auto mmd = generate_include_mermaid(diagram, *model);
+        auto src = generate_include_mermaid(diagram, *model);
 
-        save_mermaid(config.output_directory(), diagram->name + ".mmd", mmd);
+        mermaid::AliasMatcher _A(src);
+        using mermaid::HasLink;
+        using mermaid::IsFile;
+        using mermaid::IsFolder;
+
+        REQUIRE_THAT(src, IsFolder(_A("lib1")));
+        REQUIRE_THAT(src, IsFolder(_A("lib2")));
+        REQUIRE_THAT(src, IsFile(_A("lib1.h")));
+        REQUIRE_THAT(src, IsFile(_A("lib2.h")));
+        REQUIRE_THAT(src, !IsFile(_A("lib2_detail.h")));
+        REQUIRE_THAT(src, IsFile(_A("t40002.cc")));
+        REQUIRE_THAT(src, IsFile(_A("lib1.cc")));
+        REQUIRE_THAT(src, IsFile(_A("lib2.cc")));
+
+        REQUIRE_THAT(src, !IsFile(_A("string")));
+
+        REQUIRE_THAT(src, IsAssociation(_A("t40002.cc"), _A("lib1.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("lib1.h"), _A("lib2.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("lib1.cc"), _A("lib1.h")));
+        REQUIRE_THAT(src, IsAssociation(_A("lib2.cc"), _A("lib2.h")));
+
+        REQUIRE_THAT(src,
+            HasLink(_A("t40002.cc"),
+                fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
+                            "t40002/src/t40002.cc#L0",
+                    clanguml::util::get_git_commit()),
+                "t40002.cc"));
+
+        REQUIRE_THAT(src,
+            HasLink(_A("lib1.cc"),
+                fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
+                            "t40002/src/lib1/lib1.cc#L0",
+                    clanguml::util::get_git_commit()),
+                "lib1.cc"));
+
+        REQUIRE_THAT(src,
+            HasLink(_A("lib1.h"),
+                fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
+                            "t40002/include/lib1/lib1.h#L0",
+                    clanguml::util::get_git_commit()),
+                "lib1.h"));
+
+        REQUIRE_THAT(src,
+            HasLink(_A("lib2.h"),
+                fmt::format("https://github.com/bkryza/clang-uml/blob/{}/tests/"
+                            "t40002/include/lib2/lib2.h#L0",
+                    clanguml::util::get_git_commit()),
+                "lib2.h"));
+
+        save_mermaid(config.output_directory(), diagram->name + ".mmd", src);
     }
 }
diff --git a/tests/t40003/test_case.h b/tests/t40003/test_case.h
index bcadef1a..88bb5bf7 100644
--- a/tests/t40003/test_case.h
+++ b/tests/t40003/test_case.h
@@ -29,25 +29,25 @@ TEST_CASE("t40003", "[test-case][include]")
     REQUIRE(model->name() == "t40003_include");
 
     {
-        auto puml = generate_include_puml(diagram, *model);
+        auto src = generate_include_puml(diagram, *model);
 
-        AliasMatcher _A(puml);
+        AliasMatcher _A(src);
 
-        REQUIRE_THAT(puml, StartsWith("@startuml"));
-        REQUIRE_THAT(puml, EndsWith("@enduml\n"));
+        REQUIRE_THAT(src, StartsWith("@startuml"));
+        REQUIRE_THAT(src, EndsWith("@enduml\n"));
 
-        REQUIRE_THAT(puml, IsFolder("dependants"));
-        REQUIRE_THAT(puml, IsFolder("dependencies"));
+        REQUIRE_THAT(src, IsFolder("dependants"));
+        REQUIRE_THAT(src, IsFolder("dependencies"));
 
-        REQUIRE_THAT(puml, IsFile("t1.h"));
-        REQUIRE_THAT(puml, IsFile("t2.h"));
-        REQUIRE_THAT(puml, IsFile("t3.h"));
+        REQUIRE_THAT(src, IsFile("t1.h"));
+        REQUIRE_THAT(src, IsFile("t2.h"));
+        REQUIRE_THAT(src, IsFile("t3.h"));
 
-        REQUIRE_THAT(puml, !IsFile("t4.h"));
-        REQUIRE_THAT(puml, IsFile("t5.h"));
-        REQUIRE_THAT(puml, !IsFile("t6.h"));
+        REQUIRE_THAT(src, !IsFile("t4.h"));
+        REQUIRE_THAT(src, IsFile("t5.h"));
+        REQUIRE_THAT(src, !IsFile("t6.h"));
 
-        save_puml(config.output_directory(), diagram->name + ".puml", puml);
+        save_puml(config.output_directory(), diagram->name + ".puml", src);
     }
 
     {
@@ -76,8 +76,24 @@ TEST_CASE("t40003", "[test-case][include]")
     }
 
     {
-        auto mmd = generate_include_mermaid(diagram, *model);
+        auto src = generate_include_mermaid(diagram, *model);
 
-        save_mermaid(config.output_directory(), diagram->name + ".mmd", mmd);
+        mermaid::AliasMatcher _A(src);
+        using mermaid::HasLink;
+        using mermaid::IsFile;
+        using mermaid::IsFolder;
+
+        REQUIRE_THAT(src, IsFolder(_A("dependants")));
+        REQUIRE_THAT(src, IsFolder(_A("dependencies")));
+
+        REQUIRE_THAT(src, IsFile(_A("t1.h")));
+        REQUIRE_THAT(src, IsFile(_A("t2.h")));
+        REQUIRE_THAT(src, IsFile(_A("t3.h")));
+
+        REQUIRE_THAT(src, !IsFile(_A("t4.h")));
+        REQUIRE_THAT(src, IsFile(_A("t5.h")));
+        REQUIRE_THAT(src, !IsFile(_A("t6.h")));
+
+        save_mermaid(config.output_directory(), diagram->name + ".mmd", src);
     }
 }
diff --git a/tests/test_cases.h b/tests/test_cases.h
index 6b2b8bf3..12d4a6de 100644
--- a/tests/test_cases.h
+++ b/tests/test_cases.h
@@ -430,6 +430,8 @@ struct AliasMatcher {
             std::regex{"class\\s" + alias_regex + "\\[\"" + name + "\"\\]"});
         patterns.push_back(
             std::regex{"subgraph\\s" + alias_regex + "\\[" + name + "\\]"});
+        patterns.push_back(
+            std::regex{"\\s\\s" + alias_regex + "\\[" + name + "\\]"}); // file
 
         std::smatch base_match;
 
@@ -739,7 +741,13 @@ ContainsMatcher IsPackageDependency(std::string const &from,
     return ContainsMatcher(
         CasedString(fmt::format("{} -.-> {}", from, to), caseSensitivity));
 }
-
+ContainsMatcher IsIncludeDependency(std::string const &from,
+    std::string const &to,
+    CaseSensitive::Choice caseSensitivity = CaseSensitive::Yes)
+{
+    return ContainsMatcher(
+        CasedString(fmt::format("{} -.-> {}", from, to), caseSensitivity));
+}
 }
 
 ContainsMatcher IsConstraint(std::string const &from, std::string const &to,
@@ -1105,6 +1113,20 @@ ContainsMatcher IsFile(std::string const &str,
         CasedString("file \"" + str + "\"", caseSensitivity));
 }
 
+namespace mermaid {
+ContainsMatcher IsFolder(std::string const &str,
+    CaseSensitive::Choice caseSensitivity = CaseSensitive::Yes)
+{
+    return ContainsMatcher(CasedString("subgraph " + str, caseSensitivity));
+}
+
+ContainsMatcher IsFile(std::string const &str,
+    CaseSensitive::Choice caseSensitivity = CaseSensitive::Yes)
+{
+    return ContainsMatcher(CasedString(str + "[", caseSensitivity));
+}
+}
+
 ContainsMatcher IsDeprecated(std::string const &str,
     CaseSensitive::Choice caseSensitivity = CaseSensitive::Yes)
 {
diff --git a/util/generate_mermaid.py b/util/generate_mermaid.py
index 45e6366a..b85cfc94 100644
--- a/util/generate_mermaid.py
+++ b/util/generate_mermaid.py
@@ -52,7 +52,7 @@ if not files:
 ok = 0
 
 
-with ThreadPoolExecutor(max_workers=10) as executor:
+with ThreadPoolExecutor(max_workers=16) as executor:
     result = all(executor.map(generate_mermaid_diagram, files))