implement some unit tests

Author: dimaqq

tracing/test/conftest.py

@@ -90,3 +90,13 @@ def setup_tracing(monkeypatch: pytest.MonkeyPatch, juju_context: _JujuContext):
     # - forcibly reset the opentelemetry global state
     #   - tracing provider span processor, as that holds the helper thread
     #   - the tracing provider, perhaps?
+
+
+@pytest.fixture
+def sample_charm():
+    extra = str(Path(__file__).parent / 'sample_charm/src')
+    sys.path.append(extra)
+    from charm import SampleCharm
+
+    yield SampleCharm
+    sys.path.remove(extra)

tracing/test/sample_charm/src/charm.py

@@ -18,7 +18,7 @@
 import ops
 
 
-class Charm(ops.CharmBase):
+class SampleCharm(ops.CharmBase):
     def __init__(self, framework: ops.Framework):
         super().__init__(framework)
         self.tracing = ops.tracing.Tracing(
@@ -35,4 +35,4 @@ def _on_collect_status(self, event: ops.CollectStatusEvent):
 
 
 if __name__ == '__main__':
-    ops.main(Charm)
+    ops.main(SampleCharm)

tracing/test/test_backend.py

@@ -13,7 +13,32 @@
 # limitations under the License.
 from __future__ import annotations
 
+import pytest
 
-def test_set_destination_again(): ...
-def test_set_destination_none(): ...
-def test_set_destination(): ...
+import ops_tracing
+from ops_tracing.const import Config
+
+
+def test_unset_destination(setup_tracing: None):
+    assert ops_tracing.backend._exporter
+    ops_tracing.set_destination(None, None)
+    assert ops_tracing.backend._exporter.buffer.get_destination() == Config(None, None)
+
+
+def test_set_destination(setup_tracing: None):
+    assert ops_tracing.backend._exporter
+    ops_tracing.set_destination('http://a.com', None)
+    assert ops_tracing.backend._exporter.buffer.get_destination() == Config('http://a.com', None)
+
+
+def test_set_destination_again(setup_tracing: None):
+    assert ops_tracing.backend._exporter
+    ops_tracing.set_destination('http://a.com', None)
+    ops_tracing.set_destination('http://a.com', None)
+
+
+@pytest.mark.parametrize('url', ['file:///etc/passwd', 'gopher://aaa'])
+def test_set_destination_invalid_url(setup_tracing: None, url: str):
+    assert ops_tracing.backend._exporter
+    with pytest.raises(ValueError):
+        ops_tracing.set_destination(url, None)

tracing/test/test_nothing.py

@@ -15,6 +15,7 @@
 
 from __future__ import annotations
 
+from typing import Type
 from unittest.mock import Mock
 
 import pytest
@@ -23,13 +24,12 @@
 import ops.testing
 
 _pydantic = pytest.importorskip('pydantic')
-from test.fixme_charm.src.charm import Charm  # noqa: E402
 
 pytestmark = pytest.mark.filterwarnings('ignore::pydantic.PydanticDeprecatedSince20')
 
 
-def test_charm_runs():
-    ctx = ops.testing.Context(Charm)
+def test_charm_runs(sample_charm: Type[ops.CharmBase]):
+    ctx = ops.testing.Context(sample_charm)
     state_in = ops.testing.State()
     state_out = ctx.run(ctx.on.start(), state_in)
     assert isinstance(state_out.unit_status, ops.ActiveStatus)
@@ -42,28 +42,31 @@ def mock_destination(monkeypatch: pytest.MonkeyPatch) -> Mock:
     return rv
 
 
-def test_no_tracing_destination(mock_destination: Mock):
-    ctx = ops.testing.Context(Charm)
+def test_no_tracing_destination(sample_charm: Type[ops.CharmBase], mock_destination: Mock):
+    ctx = ops.testing.Context(sample_charm)
     state = ops.testing.State()
     ctx.run(ctx.on.start(), state)
     mock_destination.assert_called_with(url=None, ca=None)
 
 
-def test_http_tracing_destination(mock_destination: Mock, http_relation: ops.testing.Relation):
-    ctx = ops.testing.Context(Charm)
+def test_http_tracing_destination(
+    sample_charm: Type[ops.CharmBase], mock_destination: Mock, http_relation: ops.testing.Relation
+):
+    ctx = ops.testing.Context(sample_charm)
     state = ops.testing.State(relations={http_relation})
     ctx.run(ctx.on.relation_changed(http_relation), state)
     mock_destination.assert_called_with(url='http://tracing.example:4318/v1/traces', ca=None)
 
 
 @pytest.mark.parametrize('relation_to_poke', [0, 1])
 def test_https_tracing_destination(
+    sample_charm: Type[ops.CharmBase],
     mock_destination: Mock,
     https_relation: ops.testing.Relation,
     ca_relation: ops.testing.Relation,
     relation_to_poke: int,
 ):
-    ctx = ops.testing.Context(Charm)
+    ctx = ops.testing.Context(sample_charm)
     state = ops.testing.State(relations={https_relation, ca_relation})
     ctx.run(ctx.on.relation_changed([https_relation, ca_relation][relation_to_poke]), state)
     mock_destination.assert_called_with(url='https://tls.example/v1/traces', ca='FIRST\nSECOND')