feldera · blp · Mar 13, 2026 · Mar 4, 2026 · Mar 4, 2026 · Mar 4, 2026
diff --git a/crates/adapters/src/transport/nats/input.rs b/crates/adapters/src/transport/nats/input.rs
diff --git a/crates/adapters/src/transport/nats/input/test.rs b/crates/adapters/src/transport/nats/input/test.rs
diff --git a/crates/adapters/src/transport/nats/input/test/control_tests.rs b/crates/adapters/src/transport/nats/input/test/control_tests.rs
@@ -0,0 +1,328 @@
+use super::controller_framework::*;
+use anyhow::Result as AnyResult;
+
+// ---------------------------------------------------------------------------
+// Fault Tolerance Cycles
+// ---------------------------------------------------------------------------
+
+#[test]
+fn test_nats_ft_simple() {
+    use NatsControllerAction::*;
+    run_nats_ft_default(&[
+        StartNats,
+        CreateStream,
+        RunFtCycle {
+            publish: 5,
+            checkpoint: true,
+        },
+    ]);
+}
+
+#[test]
+fn test_nats_ft_with_checkpoints() {
+    use NatsControllerAction::*;
+    run_nats_ft_default(&[
+        StartNats,
+        CreateStream,
+        RunFtCycle {
+            publish: 10,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 15,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 20,
+            checkpoint: true,
+        },
+    ]);
+}
+
+#[test]
+fn test_nats_ft_without_checkpoints() {
+    use NatsControllerAction::*;
+    run_nats_ft_default(&[
+        StartNats,
+        CreateStream,
+        RunFtCycle {
+            publish: 10,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 15,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 20,
+            checkpoint: false,
+        },
+    ]);
+}
+
+#[test]
+fn test_nats_ft_alternating() {
+    use NatsControllerAction::*;
+    run_nats_ft_default(&[
+        StartNats,
+        CreateStream,
+        RunFtCycle {
+            publish: 10,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 15,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 20,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 10,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 15,
+            checkpoint: true,
+        },
+    ]);
+}
+
+#[test]
+fn test_nats_ft_initially_zero_without_checkpoint() {
+    use NatsControllerAction::*;
+    run_nats_ft_default(&[
+        StartNats,
+        CreateStream,
+        RunFtCycle {
+            publish: 0,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 10,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 0,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 15,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 10,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 20,
+            checkpoint: true,
+        },
+    ]);
+}
+
+#[test]
+fn test_nats_ft_initially_zero_with_checkpoint() {
+    use NatsControllerAction::*;
+    run_nats_ft_default(&[
+        StartNats,
+        CreateStream,
+        RunFtCycle {
+            publish: 0,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 10,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 0,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 15,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 10,
+            checkpoint: false,
+        },
+        RunFtCycle {
+            publish: 20,
+            checkpoint: true,
+        },
+    ]);
+}
+
+#[test]
+fn test_nats_ft_empty_step_checkpoint() {
+    use NatsControllerAction::*;
+    run_nats_ft_default(&[
+        StartNats,
+        CreateStream,
+        RunFtCycle {
+            publish: 5,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 0,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 10,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 0,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 0,
+            checkpoint: true,
+        },
+        RunFtCycle {
+            publish: 10,
+            checkpoint: true,
+        },
+    ]);
+}
+
+// ---------------------------------------------------------------------------
+// Fault Tolerance Replay and Stream Lifecycle
+// ---------------------------------------------------------------------------
+
+/// Tests that replay fails with an error (rather than looping forever) when the
+/// stream has been purged and the checkpointed messages no longer exist.
+///
+/// Scenario:
+/// 1. Publish 5 messages, run pipeline, checkpoint (sequences committed)
+/// 2. Publish 5 more messages, consume them but do NOT checkpoint, stop
+/// 3. Purge the stream (all messages deleted)
+/// 4. Start pipeline — FT framework sends a Replay for the uncommitted
+///    sequences, but those messages are gone -> expect fatal error
+#[test]
+fn test_nats_ft_replay_after_stream_purge() -> AnyResult<()> {
+    use NatsControllerAction::*;
+    run_nats_controller_test(
+        NatsControllerRunner::new()?.with_inactivity_timeout_secs(1),
+        &[
+            StartNats,
+            CreateStream,
+            RunFtCycle {
+                publish: 5,
+                checkpoint: true,
+            },
+            RunFtCycle {
+                publish: 5,
+                checkpoint: false,
+            },
+            PurgeStream,
+            ExpectStartupFatal,
+        ],
+    )
+}
+
+/// Tests rapid restart+replay with a named consumer.
+///
+/// This reproduces a bug where the previous ordered consumer hadn't expired yet,
+/// causing "consumer already exists" errors. The fix generates unique consumer names
+/// by appending a UUID suffix when a name is explicitly configured.
+#[test]
+fn test_nats_ft_with_named_consumer() -> AnyResult<()> {
+    use NatsControllerAction::*;
+    run_nats_controller_test(
+        NatsControllerRunner::new()?.with_consumer_name("my_named_consumer"),
+        &[
+            StartNats,
+            CreateStream,
+            RunFtCycle {
+                publish: 5,
+                checkpoint: true,
+            },
+            RunFtCycle {
+                publish: 5,
+                checkpoint: true,
+            },
+            RunFtCycle {
+                publish: 0,
+                checkpoint: true,
+            },
+        ],
+    )
+}
+
+/// Checkpoint, delete+recreate stream, then restart. Replay should fail
+/// because the committed sequence numbers no longer exist in the new stream.
+#[test]
+fn test_nats_ft_stream_deletion_and_recreation() -> AnyResult<()> {
+    use NatsControllerAction::*;
+    run_nats_controller_test(
+        NatsControllerRunner::new()?.with_inactivity_timeout_secs(1),
+        &[
+            StartNats,
+            CreateStream,
+            // Round 1: publish 5 records, consume and checkpoint.
+            RunFtCycle {
+                publish: 5,
+                checkpoint: true,
+            },
+            // Round 2: publish 5 more, consume but do NOT checkpoint.
+            RunFtCycle {
+                publish: 5,
+                checkpoint: false,
+            },
+            // Delete and recreate the stream — all old messages are gone.
+            DeleteStream,
+            CreateStream,
+            // Restart: FT framework tries to replay uncommitted sequences,
+            // but they don't exist in the fresh stream -> fatal startup error.
+            ExpectStartupFatal,
+        ],
+    )
+}
+
+/// Checkpoint, delete+recreate stream, publish new data, and restart.
+/// Even with a fully checkpointed round, the checkpoint resume sequence no
+/// longer matches the recreated stream and startup should fail fast.
+#[test]
+fn test_nats_ft_stream_deletion_after_full_checkpoint() -> AnyResult<()> {
+    use NatsControllerAction::*;
+    run_nats_controller_test(
+        NatsControllerRunner::new()?,
+        &[
+            StartNats,
+            CreateStream,
+            // Round 1: publish and checkpoint everything.
+            RunFtCycle {
+                publish: 5,
+                checkpoint: true,
+            },
+            // Delete and recreate stream — but everything was checkpointed,
+            // so nothing needs replaying.
+            DeleteStream,
+            CreateStream,
+            // Resume metadata points at old stream sequence space; startup fails fatally.
+            ExpectStartupFatal,
+        ],
+    )
+}
+
+// ---------------------------------------------------------------------------
+// Startup Behavior
+// ---------------------------------------------------------------------------
+
+/// Startup should enter retrying error mode when the server is up but the
+/// configured stream has not been created yet.
+#[test]
+fn test_nats_ft_startup_retries_when_stream_missing() -> AnyResult<()> {
+    use NatsControllerAction::*;
+    run_nats_controller_test(
+        NatsControllerRunner::new()?.with_inactivity_timeout_secs(1),
+        &[
+            StartNats,
+            // Intentionally skip CreateStream to force startup retry mode.
+            ExpectStartupRetrying,
+        ],
+    )
+}