some more meta autoload tests

tests/test_charm_spec_autoload.py

@@ -0,0 +1,80 @@
+import importlib
+import sys
+import tempfile
+from pathlib import Path
+from typing import Type
+
+import pytest
+import yaml
+from ops.testing import CharmType
+
+from scenario import Context, Relation, State
+from scenario.context import ContextSetupError
+
+CHARM = """
+from ops import CharmBase
+
+class MyCharm(CharmBase): pass
+"""
+
+
+def import_name(name: str, source: Path) -> Type[CharmType]:
+    pkg_path = str(source.parent)
+    sys.path.append(pkg_path)
+    charm = importlib.import_module("charm")
+    obj = getattr(charm, name)
+    sys.path.remove(pkg_path)
+    return obj
+
+
+def create_tempcharm(
+    charm: str = CHARM, meta=None, actions=None, config=None, name: str = "MyCharm"
+):
+    root = Path(tempfile.TemporaryDirectory().name)
+
+    src = root / "src"
+    src.mkdir(parents=True)
+    charmpy = src / "charm.py"
+    charmpy.write_text(charm)
+
+    if meta is not None:
+        (root / "metadata.yaml").write_text(yaml.safe_dump(meta))
+
+    if actions is not None:
+        (root / "actions.yaml").write_text(yaml.safe_dump(actions))
+
+    if config is not None:
+        (root / "config.yaml").write_text(yaml.safe_dump(config))
+
+    return import_name(name, charmpy)
+
+
+def test_meta_autoload(tmp_path):
+    charm = create_tempcharm(meta={"name": "foo"})
+    ctx = Context(charm)
+    ctx.run("start", State())
+
+
+def test_no_meta_raises(tmp_path):
+    charm = create_tempcharm()
+    with pytest.raises(ContextSetupError):
+        Context(charm)
+
+
+def test_relations_ok(tmp_path):
+    charm = create_tempcharm(
+        meta={"name": "josh", "requires": {"cuddles": {"interface": "arms"}}}
+    )
+    # this would fail if there were no 'cuddles' relation defined in meta
+    Context(charm).run("start", State(relations=[Relation("cuddles")]))
+
+
+def test_config_defaults(tmp_path):
+    charm = create_tempcharm(
+        meta={"name": "josh"},
+        config={"options": {"foo": {"type": "bool", "default": True}}},
+    )
+    # this would fail if there were no 'cuddles' relation defined in meta
+    with Context(charm).manager("start", State()) as mgr:
+        mgr.run()
+        assert mgr.charm.config["foo"] is True

tox.ini

@@ -22,14 +22,13 @@ package = wheel
 wheel_build_env = .pkg
 description = unit tests
 deps =
-    coverage[toml]
     jsonpatch
     pytest
+    pytest-cov
+setenv =
+    PYTHONPATH = {toxinidir}
 commands =
-    coverage run \
-      --source={[vars]src_path} \
-      -m pytest -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tst_path}
-    coverage html
+    pytest --cov-report html -v --tb native --log-cli-level=INFO -s {posargs} {[vars]tst_path}
 
 [testenv:lint]
 description = Format the code base to adhere to our styles, and complain about what we cannot do automatically.
@@ -48,7 +47,7 @@ deps =
     coverage[toml]
     isort
 commands =
-    black --check tests scenario
+    black --check {[vars]tst_path} {[vars]src_path}
     isort --check-only --profile black {[vars]tst_path}
 
 [testenv:fmt]
@@ -58,5 +57,5 @@ deps =
     black
     isort
 commands =
-    black tests scenario
-    isort --profile black tests scenario
+    black {[vars]tst_path} {[vars]src_path}
+    isort --profile black {[vars]tst_path} {[vars]src_path}