fix(test): remove tests that are not relevant any more

With the new snapshot format we break compatibility with all previous
snapshot format versions. This commits removes all the tests that were
checking functional correctness and performance of loading older
snapshots in the current Firecracker binary.

In the future, it might be that two Firecracker binaries support the
same snapshot versions. When that happens we should thing of a proper
way to test that this works, but the current tests are not fit for
purpose.

Signed-off-by: Babis Chalios <bchalios@amazon.es>

tests/integration_tests/functional/test_mmds.py

@@ -610,40 +610,6 @@ def test_mmds_snapshot(uvm_nano, microvm_factory, version):
     )
 
 
-def test_mmds_older_snapshot(
-    microvm_factory, guest_kernel, rootfs, firecracker_release
-):
-    """
-    Test MMDS behavior restoring older snapshots in the current version.
-
-    Ensures that the MMDS version is persisted or initialised with the default
-    if the FC version does not support this feature.
-    """
-
-    # due to bug fixed in commit 8dab78b
-    firecracker_version = firecracker_release.version_tuple
-    if global_props.instance == "m6a.metal" and firecracker_version < (1, 3, 3):
-        pytest.skip("incompatible with AMD and Firecracker <1.3.3")
-
-    microvm = microvm_factory.build(
-        guest_kernel,
-        rootfs,
-        fc_binary_path=firecracker_release.path,
-        jailer_binary_path=firecracker_release.jailer,
-    )
-    microvm.spawn()
-    microvm.basic_config()
-    microvm.add_net_iface()
-
-    mmds_version = "V2"
-    _validate_mmds_snapshot(
-        microvm,
-        microvm_factory,
-        mmds_version,
-        *get_firecracker_binaries(),
-    )
-
-
 def test_mmds_v2_negative(test_microvm_with_api):
     """
     Test invalid MMDS GET/PUT requests when using V2.

tests/integration_tests/functional/test_snapshot_advanced.py

@@ -15,45 +15,6 @@
 scratch_drives = ["vdb", "vdc", "vdd", "vde"]
 
 
-def test_restore_old_to_current(
-    microvm_factory, guest_kernel, rootfs_ubuntu_22, firecracker_release
-):
-    """
-    Restore snapshots from previous supported versions of Firecracker.
-
-    For each firecracker release:
-    1. Snapshot with the past release
-    2. Restore with the current build
-    """
-
-    # due to bug fixed in commit 8dab78b
-    firecracker_version = firecracker_release.version_tuple
-    if global_props.instance == "m6a.metal" and firecracker_version < (1, 3, 3):
-        pytest.skip("incompatible with AMD and Firecracker <1.3.3")
-
-    # Microvm: 2vCPU 256MB RAM, balloon, 4 disks and 4 net devices.
-    diff_snapshots = True
-    vm = microvm_factory.build(
-        guest_kernel,
-        rootfs_ubuntu_22,
-        fc_binary_path=firecracker_release.path,
-        jailer_binary_path=firecracker_release.jailer,
-    )
-    vm.spawn()
-    vm.basic_config(track_dirty_pages=True)
-    snapshot = create_snapshot_helper(
-        vm,
-        drives=scratch_drives,
-        diff_snapshots=diff_snapshots,
-        balloon=diff_snapshots,
-    )
-    vm = microvm_factory.build()
-    vm.spawn()
-    vm.restore_from_snapshot(snapshot, resume=True)
-    validate_all_devices(vm, diff_snapshots)
-    print(vm.log_data)
-
-
 def validate_all_devices(microvm, balloon):
     """Perform a basic validation for all devices of a microvm."""
     # Test that net devices have connectivity after restore.

tests/integration_tests/performance/test_snapshot_perf.py

@@ -68,72 +68,6 @@ def snapshot_resume_producer(microvm_factory, snapshot):
     return value
 
 
-@only_one_guest_kernel
-def test_older_snapshot_resume_latency(
-    microvm_factory,
-    guest_kernel,
-    rootfs,
-    firecracker_release,
-    io_engine,
-    st_core,
-):
-    """
-    Test scenario: Older snapshot load performance measurement.
-
-    With each previous firecracker version, create a snapshot and try to
-    restore in current version.
-    """
-
-    # due to bug fixed in commit 8dab78b
-    firecracker_version = firecracker_release.version_tuple
-    if global_props.instance == "m6a.metal" and firecracker_version < (1, 3, 3):
-        pytest.skip("incompatible with AMD and Firecracker <1.3.3")
-
-    vcpus, guest_mem_mib = 2, 512
-    microvm_cfg = f"{vcpus}vcpu_{guest_mem_mib}mb.json"
-    vm = microvm_factory.build(
-        guest_kernel,
-        rootfs,
-        monitor_memory=False,
-        fc_binary_path=firecracker_release.path,
-        jailer_binary_path=firecracker_release.jailer,
-    )
-    vm.spawn()
-    vm.basic_config(vcpu_count=vcpus, mem_size_mib=guest_mem_mib)
-    vm.add_net_iface()
-    vm.start()
-    # Check if guest works.
-    exit_code, _, _ = vm.ssh.run("ls")
-    assert exit_code == 0
-    snapshot = vm.snapshot_full()
-
-    st_core.name = "older_snapshot_resume_latency"
-    st_core.iterations = SAMPLE_COUNT
-    st_core.custom["guest_config"] = microvm_cfg.strip(".json")
-    st_core.custom["io_engine"] = io_engine
-    st_core.custom["snapshot_type"] = "FULL"
-
-    prod = producer.LambdaProducer(
-        func=snapshot_resume_producer,
-        func_kwargs={
-            "microvm_factory": microvm_factory,
-            "snapshot": snapshot,
-        },
-    )
-
-    cons = consumer.LambdaConsumer(
-        func=lambda cons, result: cons.consume_stat(
-            st_name="max", ms_name="latency", value=result
-        ),
-        func_kwargs={},
-    )
-    cons.set_measurement_def(LATENCY_MEASUREMENT)
-
-    st_core.add_pipe(producer=prod, consumer=cons, tag=microvm_cfg)
-    # Gather results and verify pass criteria.
-    st_core.run_exercise()
-
-
 @only_one_guest_kernel
 def test_snapshot_create_latency(
     microvm_factory,