diff --git a/src/core/config.rs b/src/core/config.rs
index b23b765..f296440 100644
--- a/src/core/config.rs
+++ b/src/core/config.rs
@@ -99,3 +99,56 @@ impl Config {
         Self::default()
     }
 }
+
+//write unit tests:
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::Path;
+    
+    // create a clean default config file for testing
+    fn create_default_config_file() {
+        let toml = toml::to_string(&Config::default()).unwrap();
+        fs::write(&*CONFIG_FILE, toml).expect("Could not write config file to disk!");
+    }
+    
+    #[test]
+    fn test_create_default_config_file() {
+        create_default_config_file();
+        assert!(CONFIG_FILE.exists());
+    }
+
+    #[test]
+    fn test_load_configuration_file(){
+        create_default_config_file();
+        let config = Config::load_configuration_file();
+        assert_eq!(config.devices.len(), 0);
+        assert_eq!(config.general.theme, Theme::default().to_string());
+        assert_eq!(config.general.expert_mode, false);
+        assert_eq!(config.general.backup_folder, CACHE_DIR.join("backups"));
+    }
+
+    #[test]
+    fn test_save_changes() {
+        let mut settings = Settings::default();
+        let device_id = "test_device".to_string();
+        settings.device.device_id = device_id.clone();
+        Config::save_changes(&settings, &device_id);
+        let config = Config::load_configuration_file();
+        assert_eq!(config.devices[0].device_id, device_id);
+    }
+
+    #[test]
+    fn test_default_config() {
+        let config = Config::default();
+        assert_eq!(config.devices.len(), 0);
+        assert_eq!(config.general.theme, Theme::default().to_string());
+        assert_eq!(config.general.expert_mode, false);
+        assert_eq!(config.general.backup_folder, CACHE_DIR.join("backups"));
+    }
+
+    #[test]
+    fn test_config_file_path() {
+        assert_eq!(&*CONFIG_FILE, Path::new(&*CONFIG_DIR.join("config.toml")));
+    }
+}
\ No newline at end of file
diff --git a/src/gui/style.rs b/src/gui/style.rs
index ac32942..09a59e9 100644
--- a/src/gui/style.rs
+++ b/src/gui/style.rs
@@ -573,3 +573,23 @@ impl rule::StyleSheet for Theme {
         }
     }
 }
+
+// Unit tests
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_palette() {
+        let palette = Theme::default().palette();
+
+        assert_ne!(palette.base.background, Color::BLACK);
+        assert_ne!(palette.base.foreground, Color::BLACK);
+        assert_ne!(palette.normal.primary, Color::BLACK);
+        assert_ne!(palette.normal.surface, Color::BLACK);
+        assert_ne!(palette.bright.primary, Color::BLACK);
+        assert_ne!(palette.bright.surface, Color::BLACK);
+        assert_ne!(palette.normal.error, Color::BLACK);
+        assert_ne!(palette.bright.error, Color::BLACK);
+    }
+}
\ No newline at end of file