Add architecture integration tests

tests/conftest.py

@@ -2,6 +2,7 @@
 # See LICENSE file for licensing details.
 
 import argparse
+import subprocess
 
 import pytest
 
@@ -32,6 +33,30 @@ def pytest_configure(config):
         config.option.mysql_router_charm_bases_index = 1
 
 
+@pytest.fixture(autouse=True)
+def architecture() -> str:
+    return subprocess.run(
+        ["dpkg", "--print-architecture"],
+        capture_output=True,
+        check=True,
+        encoding="utf-8",
+    ).stdout.strip()
+
+
+@pytest.fixture
+def only_amd64(architecture):
+    """Pretty way to skip ARM tests."""
+    if architecture != "amd64":
+        pytest.skip("Requires amd64 architecture")
+
+
+@pytest.fixture
+def only_arm64(architecture):
+    """Pretty way to skip AMD tests."""
+    if architecture != "arm64":
+        pytest.skip("Requires arm64 architecture")
+
+
 @pytest.fixture
 def only_with_juju_secrets(juju_has_secrets):
     """Pretty way to skip Juju 3 tests."""

tests/integration/helpers.py

@@ -5,9 +5,11 @@
 import logging
 import subprocess
 import tempfile
-from typing import Dict, List, Optional
+from pathlib import Path
+from typing import Dict, List, Optional, Union
 
 import tenacity
+import yaml
 from juju.model import Model
 from juju.unit import Unit
 from pytest_operator.plugin import OpsTest
@@ -486,3 +488,17 @@ async def get_machine_address(ops_test: OpsTest, unit: Unit) -> str:
             return line.split()[2]
 
     assert False, "Unable to find the unit's machine"
+
+
+async def get_charm(charm_path: Union[str, Path], architecture: str, bases_index: int) -> Path:
+    """Fetches packed charm from CI runner without checking for architecture."""
+    charm_path = Path(charm_path)
+    charmcraft_yaml = yaml.safe_load((charm_path / "charmcraft.yaml").read_text())
+    assert charmcraft_yaml["type"] == "charm"
+
+    base = charmcraft_yaml["bases"][bases_index]
+    build_on = base.get("build-on", [base])[0]
+    version = build_on["channel"]
+    packed_charms = list(charm_path.glob(f"*{version}-{architecture}.charm"))
+
+    return packed_charms[0].resolve(strict=True)

tests/integration/test_architecture.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+# Copyright 2024 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+import pytest
+from pytest_operator.plugin import OpsTest
+
+from .helpers import get_charm
+
+MYSQL_ROUTER_APP_NAME = "mysql-router"
+
+
+@pytest.mark.group(1)
+@pytest.mark.usefixtures("only_amd64")
+async def test_arm_charm_on_amd_host(ops_test: OpsTest) -> None:
+    """Tries deploying an arm64 charm on amd64 host."""
+    charm = await get_charm(".", "arm64", 2)
+
+    await ops_test.model.deploy(
+        charm,
+        application_name=MYSQL_ROUTER_APP_NAME,
+        num_units=1,
+        config={"profile": "testing"},
+        base="[email protected]",
+    )
+
+    await ops_test.model.wait_for_idle(
+        apps=[MYSQL_ROUTER_APP_NAME],
+        status="error",
+        raise_on_error=False,
+    )
+
+
+@pytest.mark.group(1)
+@pytest.mark.usefixtures("only_arm64")
+async def test_amd_charm_on_arm_host(ops_test: OpsTest) -> None:
+    """Tries deploying an amd64 charm on arm64 host."""
+    charm = await get_charm(".", "amd64", 1)
+
+    await ops_test.model.deploy(
+        charm,
+        application_name=MYSQL_ROUTER_APP_NAME,
+        num_units=1,
+        config={"profile": "testing"},
+        base="[email protected]",
+    )
+
+    await ops_test.model.wait_for_idle(
+        apps=[MYSQL_ROUTER_APP_NAME],
+        status="error",
+        raise_on_error=False,
+    )