diff --git a/src-tauri/tests/calendar_import_smoke_test.rs b/src-tauri/tests/calendar_import_smoke_test.rs
new file mode 100644
index 0000000..b5bc8ac
--- /dev/null
+++ b/src-tauri/tests/calendar_import_smoke_test.rs
@@ -0,0 +1,113 @@
+use whispassist_lib::models::{AttendeeInfo, CalendarEvent, ImportedEvent};
+use whispassist_lib::storage::{SqliteStore, Store};
+
+fn event(uid: &str, subject: &str) -> ImportedEvent {
+    ImportedEvent {
+        event: CalendarEvent {
+            id: uuid::Uuid::new_v4().to_string(),
+            source: "pst".to_string(),
+            subject: Some(subject.to_string()),
+            organizer: Some("Jordan Lee".to_string()),
+            starts_at: Some(1_782_896_400),
+            ends_at: Some(1_782_900_000),
+            description: Some("Agenda".to_string()),
+            raw_uid: Some(uid.to_string()),
+        },
+        attendees: vec![
+            AttendeeInfo {
+                name: "Alex Kim".to_string(),
+                email: Some("alex@example.com".to_string()),
+                role: Some("required".to_string()),
+            },
+            AttendeeInfo {
+                name: "No Email Person".to_string(),
+                email: None,
+                role: None,
+            },
+        ],
+    }
+}
+
+#[tokio::test]
+async fn import_calendar_events_dedups_by_source_and_raw_uid() {
+    std::env::set_var(
+        "LOCALAPPDATA",
+        std::env::temp_dir().join(format!("wa-caltest-{}", uuid::Uuid::new_v4())),
+    );
+    let store = SqliteStore::connect().await.unwrap();
+
+    let n1 = store
+        .import_calendar_events(vec![event("uid-1", "Sprint planning")])
+        .await
+        .unwrap();
+    assert_eq!(n1, 1);
+
+    let n2 = store
+        .import_calendar_events(vec![
+            event("uid-1", "Sprint planning (rescheduled)"),
+            event("uid-2", "Retro"),
+        ])
+        .await
+        .unwrap();
+    assert_eq!(n2, 2);
+
+    let n3 = store
+        .import_calendar_events(vec![event("uid-1", "Sprint planning (rescheduled)")])
+        .await
+        .unwrap();
+    assert_eq!(n3, 1);
+
+    // Verify actual row-level dedup, not just the returned counts.
+    let pool = sqlx::sqlite::SqlitePool::connect(&format!(
+        "sqlite:{}",
+        whispassist_lib::paths::db_path().display()
+    ))
+    .await
+    .unwrap();
+
+    let event_count: i64 =
+        sqlx::query_scalar("SELECT COUNT(*) FROM calendar_events WHERE raw_uid = 'uid-1'")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+    assert_eq!(
+        event_count, 1,
+        "re-importing uid-1 must update in place, not duplicate"
+    );
+
+    let subject: String =
+        sqlx::query_scalar("SELECT subject FROM calendar_events WHERE raw_uid = 'uid-1'")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+    assert_eq!(subject, "Sprint planning (rescheduled)");
+
+    let total_events: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM calendar_events")
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+    assert_eq!(total_events, 2, "uid-1 and uid-2 only");
+
+    let no_email_rows: i64 =
+        sqlx::query_scalar("SELECT COUNT(*) FROM participants WHERE name = 'No Email Person'")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+    assert_eq!(
+        no_email_rows, 1,
+        "repeat no-email attendee must not duplicate the participant row"
+    );
+
+    let alex_rows: i64 =
+        sqlx::query_scalar("SELECT COUNT(*) FROM participants WHERE email = 'alex@example.com'")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+    assert_eq!(alex_rows, 1);
+
+    let links: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM calendar_event_participants")
+        .fetch_one(&pool)
+        .await
+        .unwrap();
+    assert_eq!(links, 4, "2 events x 2 attendees each");
+}