diff --git a/src/convenience.cpp b/src/convenience.cpp
index 68c380c..a8b1224 100644
--- a/src/convenience.cpp
+++ b/src/convenience.cpp
@@ -57,26 +57,27 @@ PluginTags GetPluginTags(const std::shared_ptr<DatabaseInterface> db, const std:
 PluginCleanliness GetPluginCleanliness(const std::shared_ptr<DatabaseInterface> db, const std::string& plugin, bool evaluateConditions) {
   auto metadata = db->GetPluginMetadata(plugin, true, evaluateConditions);
 
-  if (metadata.has_value()) {
-    if (metadata.value().GetDirtyInfo().empty()) {
-      if (metadata.value().GetCleanInfo().empty()) {
-        return PluginCleanliness::unknown;
-      }
-      else {
-        return PluginCleanliness::clean;
-      }
-    }
-    else if (!metadata.value().GetCleanInfo().empty()) {
-      return PluginCleanliness::unknown;
-    }
+  if (!metadata.has_value()) {
+    return PluginCleanliness::unknown;
+  }
 
-    for (const auto& info : metadata.value().GetDirtyInfo()) {
-      if (info.ChooseInfo("en").GetText().find("Do not clean") != std::string::npos) {
-        return PluginCleanliness::do_not_clean;
-      }
+  auto dirtyInfo = metadata.value().GetDirtyInfo();
+  auto cleanInfo = metadata.value().GetCleanInfo();
+
+  if (dirtyInfo.empty() == cleanInfo.empty()) {
+    return PluginCleanliness::unknown;
+  }
+
+  if (!cleanInfo.empty()) {
+    return PluginCleanliness::clean;
+  }
+
+  for (const auto& info : dirtyInfo) {
+    if (info.ChooseInfo("en").GetText().find("Do not clean") != std::string::npos) {
+      return PluginCleanliness::do_not_clean;
     }
   }
 
-  return PluginCleanliness::unknown;
+  return PluginCleanliness::dirty;
 }
 }
diff --git a/test/masterlist.yaml b/test/masterlist.yaml
index 106dff3..248de5d 100644
--- a/test/masterlist.yaml
+++ b/test/masterlist.yaml
@@ -28,3 +28,27 @@ plugins:
       - Scripts
       - Stats
       - -C.Water
+
+  - name: clean_and_dirty.esp
+    dirty:
+      - crc: 0xDEADBEEF
+        util: '[TES4Edit v4.0.0](https://www.nexusmods.com/oblivion/mods/11536)'
+    clean:
+      - crc: 0xFEEDFACE
+        util: 'TES4Edit v4.0.0'
+
+  - name: clean.esp
+    clean:
+      - crc: 0xFEEDFACE
+        util: 'TES4Edit v4.0.0'
+
+  - name: dirty.esp
+    dirty:
+      - crc: 0xDEADBEEF
+        util: '[TES4Edit v4.0.0](https://www.nexusmods.com/oblivion/mods/11536)'
+
+  - name: do_not_clean.esp
+    dirty:
+      - crc: 0xDEADBEEF
+        util: '[TES4Edit v4.0.0](https://www.nexusmods.com/oblivion/mods/11536)'
+        info: 'Do not clean. This plugin is intentionally left dirty.'
diff --git a/test/test.py b/test/test.py
index a50a93f..72e5c65 100644
--- a/test/test.py
+++ b/test/test.py
@@ -14,6 +14,7 @@ from loot_api import WrapperVersion
 from loot_api import GameType
 from loot_api import SimpleMessage
 from loot_api import MessageType
+from loot_api import PluginCleanliness
 from loot_api import create_game_handle
 from loot_api import is_compatible
 from loot_api import set_logging_callback
@@ -121,6 +122,40 @@ class TestDatabaseInterface(GameFixture):
         self.assertEqual(messages[0].type, MessageType.error)
         self.assertEqual(messages[0].text, u'This must not be activated. However, it can be useful when porting Oblivion mods to Nehrim.')
 
+    def test_get_plugin_cleanliness_should_be_unknown_if_no_dirty_or_clean_metadata_exists(self):
+        self.db.load_lists(self.masterlist_path, u'')
+
+        cleanliness = self.db.get_plugin_cleanliness(u'unknown.esp')
+
+        self.assertEqual(cleanliness, PluginCleanliness.unknown)
+
+    def test_get_plugin_cleanliness_should_be_unknown_if_dirty_and_clean_metadata_exists(self):
+        self.db.load_lists(self.masterlist_path, u'')
+
+        cleanliness = self.db.get_plugin_cleanliness(u'clean_and_dirty.esp')
+
+        self.assertEqual(cleanliness, PluginCleanliness.unknown)
+
+    def test_get_plugin_cleanliness_should_be_clean_if_only_clean_metadata_exists(self):
+        self.db.load_lists(self.masterlist_path, u'')
+
+        cleanliness = self.db.get_plugin_cleanliness(u'clean.esp')
+
+        self.assertEqual(cleanliness, PluginCleanliness.clean)
+
+    def test_get_plugin_cleanliness_should_be_dirty_if_only_dirty_metadata_exists(self):
+        self.db.load_lists(self.masterlist_path, u'')
+
+        cleanliness = self.db.get_plugin_cleanliness(u'dirty.esp')
+
+        self.assertEqual(cleanliness, PluginCleanliness.dirty)
+
+    def test_get_plugin_cleanliness_should_be_do_not_clean_if_dirty_do_not_clean_info_exists(self):
+        self.db.load_lists(self.masterlist_path, u'')
+
+        cleanliness = self.db.get_plugin_cleanliness(u'do_not_clean.esp')
+
+        self.assertEqual(cleanliness, PluginCleanliness.do_not_clean)
 
 if __name__ == '__main__':
     unittest.main()