diff --git a/tests/t90000/test_case.h b/tests/t90000/test_case.h
index a517f474..945733c5 100644
--- a/tests/t90000/test_case.h
+++ b/tests/t90000/test_case.h
@@ -1,5 +1,5 @@
 /**
- * tests/t90000/test_case.cc
+ * tests/t90000/test_case.h
  *
  * Copyright (c) 2021-2024 Bartek Kryza <bkryza@gmail.com>
  *
@@ -16,40 +16,21 @@
  * limitations under the License.
  */
 
-TEST_CASE("t90000", "[test-case][config]")
+TEST_CASE("t90000")
 {
-    auto [config, db] = load_config("t90000");
+    using namespace clanguml::test;
 
-    auto diagram = config.diagrams["t90000_class"];
+    auto [config, db, diagram, model] =
+        CHECK_CLASS_MODEL("t90000", "t90000_class");
 
-    auto model = generate_class_diagram(*db, diagram);
-
-    REQUIRE(model->name() == "t90000_class");
-
-    {
-        auto puml = generate_class_puml(diagram, *model);
-        AliasMatcher _A(puml);
-
-        REQUIRE_THAT(puml, StartsWith("@startuml"));
-        REQUIRE_THAT(puml, EndsWith("@enduml\n"));
-
-        REQUIRE_THAT(puml, IsClass(_A("Foo")));
-        REQUIRE_THAT(puml, IsClass(_A("Boo")));
-
-        save_puml(config.output_directory(), diagram->name + ".puml", puml);
-    }
-
-    {
-        auto j = generate_class_json(diagram, *model);
-
-        using namespace json;
-
-        save_json(config.output_directory(), diagram->name + ".json", j);
-    }
-
-    {
-        auto mmd = generate_class_mermaid(diagram, *model);
-
-        save_mermaid(config.output_directory(), diagram->name + ".mmd", mmd);
-    }
+    CHECK_CLASS_DIAGRAM(
+        config, diagram, *model,
+        [](const plantuml_t &src) {
+            REQUIRE(IsClass(src, "Foo"));
+            REQUIRE(IsClass(src, "Boo"));
+        },
+        [](const mermaid_t &src) {
+            REQUIRE(IsClass(src, "Foo"));
+            REQUIRE(IsClass(src, "Boo"));
+        });
 }
diff --git a/tests/t90001/test_case.h b/tests/t90001/test_case.h
index 812f5a0d..99767514 100644
--- a/tests/t90001/test_case.h
+++ b/tests/t90001/test_case.h
@@ -1,5 +1,5 @@
 /**
- * tests/t90001/test_case.cc
+ * tests/t90001/test_case.h
  *
  * Copyright (c) 2021-2024 Bartek Kryza <bkryza@gmail.com>
  *
@@ -16,8 +16,9 @@
  * limitations under the License.
  */
 
-TEST_CASE("t90001", "[test-case][config]")
+TEST_CASE("t90001")
 {
+    using namespace clanguml::test;
     using clanguml::error::empty_diagram_error;
 
     auto [config, db] = load_config("t90001");
@@ -31,12 +32,12 @@ TEST_CASE("t90001", "[test-case][config]")
 
         REQUIRE(model->name() == "t90001_class");
 
+        REQUIRE_THROWS_AS(render_class_diagram<plantuml_t>(diagram, *model),
+            empty_diagram_error);
+        REQUIRE_THROWS_AS(render_class_diagram<mermaid_t>(diagram, *model),
+            empty_diagram_error);
         REQUIRE_THROWS_AS(
-            generate_class_puml(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_class_json(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_class_mermaid(diagram, *model), empty_diagram_error);
+            render_class_diagram<json_t>(diagram, *model), empty_diagram_error);
     }
 
     {
@@ -48,12 +49,12 @@ TEST_CASE("t90001", "[test-case][config]")
 
         REQUIRE(model->name() == "t90001_sequence");
 
-        REQUIRE_THROWS_AS(
-            generate_sequence_puml(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_sequence_json(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_sequence_mermaid(diagram, *model), empty_diagram_error);
+        REQUIRE_THROWS_AS(render_sequence_diagram<plantuml_t>(diagram, *model),
+            empty_diagram_error);
+        REQUIRE_THROWS_AS(render_sequence_diagram<mermaid_t>(diagram, *model),
+            empty_diagram_error);
+        REQUIRE_THROWS_AS(render_sequence_diagram<json_t>(diagram, *model),
+            empty_diagram_error);
     }
 
     {
@@ -65,12 +66,12 @@ TEST_CASE("t90001", "[test-case][config]")
 
         REQUIRE(model->name() == "t90001_package");
 
-        REQUIRE_THROWS_AS(
-            generate_package_puml(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_package_json(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_package_mermaid(diagram, *model), empty_diagram_error);
+        REQUIRE_THROWS_AS(render_package_diagram<plantuml_t>(diagram, *model),
+            empty_diagram_error);
+        REQUIRE_THROWS_AS(render_package_diagram<mermaid_t>(diagram, *model),
+            empty_diagram_error);
+        REQUIRE_THROWS_AS(render_package_diagram<json_t>(diagram, *model),
+            empty_diagram_error);
     }
 
     {
@@ -82,11 +83,11 @@ TEST_CASE("t90001", "[test-case][config]")
 
         REQUIRE(model->name() == "t90001_include");
 
-        REQUIRE_THROWS_AS(
-            generate_include_puml(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_include_json(diagram, *model), empty_diagram_error);
-        REQUIRE_THROWS_AS(
-            generate_include_mermaid(diagram, *model), empty_diagram_error);
+        REQUIRE_THROWS_AS(render_include_diagram<plantuml_t>(diagram, *model),
+            empty_diagram_error);
+        REQUIRE_THROWS_AS(render_include_diagram<mermaid_t>(diagram, *model),
+            empty_diagram_error);
+        REQUIRE_THROWS_AS(render_include_diagram<json_t>(diagram, *model),
+            empty_diagram_error);
     }
 }
diff --git a/tests/test_cases.cc b/tests/test_cases.cc
index c18cba56..e235089b 100644
--- a/tests/test_cases.cc
+++ b/tests/test_cases.cc
@@ -1266,15 +1266,12 @@ template <> bool IsClass(json_t d, std::string name)
 #include "t40001/test_case.h"
 #include "t40002/test_case.h"
 #include "t40003/test_case.h"
-/*
-
 
 ///
 /// Other tests (e.g. configuration file)
 ///
 #include "t90000/test_case.h"
 #include "t90001/test_case.h"
-*/
 
 ///
 /// Main test function
diff --git a/tests/test_cases.h b/tests/test_cases.h
index 5732ce98..06f0d65f 100644
--- a/tests/test_cases.h
+++ b/tests/test_cases.h
@@ -51,14 +51,6 @@ using namespace clanguml::util;
 std::pair<clanguml::config::config, clanguml::common::compilation_database_ptr>
 load_config(const std::string &test_name);
 
-// std::string generate_sequence_puml(
-//     std::shared_ptr<clanguml::config::diagram> config,
-//     clanguml::sequence_diagram::model::diagram &model);
-//
-// std::string generate_class_puml(
-//     std::shared_ptr<clanguml::config::diagram> config,
-//     clanguml::class_diagram::model::diagram &model);
-
 void save_puml(const std::string &path, const std::string &puml);
 
 namespace clanguml::test {