test: added more tests (#16)

Co-authored-by: Sharang Parnerkar <parnerkarsharang@gmail.com>
Reviewed-on: #16

src/models/developer.rs

@@ -45,3 +45,63 @@ pub struct AnalyticsMetric {
     pub value: String,
     pub change_pct: f64,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn agent_entry_serde_round_trip() {
+        let agent = AgentEntry {
+            id: "a1".into(),
+            name: "RAG Agent".into(),
+            description: "Retrieval-augmented generation".into(),
+            status: "running".into(),
+        };
+        let json = serde_json::to_string(&agent).expect("serialize AgentEntry");
+        let back: AgentEntry = serde_json::from_str(&json).expect("deserialize AgentEntry");
+        assert_eq!(agent, back);
+    }
+
+    #[test]
+    fn flow_entry_serde_round_trip() {
+        let flow = FlowEntry {
+            id: "f1".into(),
+            name: "Data Pipeline".into(),
+            node_count: 5,
+            last_run: Some("2025-06-01T12:00:00Z".into()),
+        };
+        let json = serde_json::to_string(&flow).expect("serialize FlowEntry");
+        let back: FlowEntry = serde_json::from_str(&json).expect("deserialize FlowEntry");
+        assert_eq!(flow, back);
+    }
+
+    #[test]
+    fn flow_entry_with_none_last_run() {
+        let flow = FlowEntry {
+            id: "f2".into(),
+            name: "New Flow".into(),
+            node_count: 0,
+            last_run: None,
+        };
+        let json = serde_json::to_string(&flow).expect("serialize");
+        let back: FlowEntry = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(flow, back);
+        assert_eq!(back.last_run, None);
+    }
+
+    #[test]
+    fn analytics_metric_negative_change_pct() {
+        let metric = AnalyticsMetric {
+            label: "Latency".into(),
+            value: "120ms".into(),
+            change_pct: -15.5,
+        };
+        let json = serde_json::to_string(&metric).expect("serialize AnalyticsMetric");
+        let back: AnalyticsMetric =
+            serde_json::from_str(&json).expect("deserialize AnalyticsMetric");
+        assert_eq!(metric, back);
+        assert!(back.change_pct < 0.0);
+    }
+}