test(metrics): add coverage for metrics timing decorator

Closes #978

Signed-off-by: Marcel Nadzam <mnadzam@redhat.com>

Co-Authored-By: Cursor

Author: mnadzam

tests/test_metrics.py

@@ -0,0 +1,144 @@
+from __future__ import annotations
+
+import logging
+
+import pytest
+from packaging.requirements import Requirement
+from packaging.version import Version
+
+from fromager import context, metrics
+
+
+@metrics.timeit(description="test description")
+def _test_func(
+    *,
+    ctx: context.WorkContext,
+    req: Requirement | None = None,
+    version: str | None = None,
+) -> str:
+    return "ok"
+
+
+@metrics.timeit(description="test description")
+def _test_returns_version(
+    *,
+    ctx: context.WorkContext,
+    req: Requirement | None = None,
+) -> tuple[str, Version]:
+    return ("http://example.com", Version("1.2.3"))
+
+
+@metrics.timeit(description="test description")
+def _test_raises(
+    *,
+    ctx: context.WorkContext,
+    req: Requirement | None = None,
+) -> None:
+    raise RuntimeError("test error")
+
+
+def test_timeit_stores_timing(tmp_context: context.WorkContext) -> None:
+    req = Requirement("numpy>=1.0")
+
+    _test_func(ctx=tmp_context, req=req, version="1.26.0")
+
+    key = "numpy==1.26.0"
+    assert key in tmp_context.time_store
+    assert tmp_context.time_store[key]["_test_func"] > 0
+
+
+def test_timeit_stores_description(tmp_context: context.WorkContext) -> None:
+    _test_func(ctx=tmp_context)
+
+    assert tmp_context.time_description_store["_test_func"] == "test description"
+
+
+def test_timeit_no_storage_without_req(tmp_context: context.WorkContext) -> None:
+    _test_func(ctx=tmp_context, req=None, version="1.0")
+
+    assert len(tmp_context.time_store) == 0
+
+
+def test_timeit_no_storage_without_version(tmp_context: context.WorkContext) -> None:
+    req = Requirement("numpy>=1.0")
+
+    _test_func(ctx=tmp_context, req=req)
+
+    assert len(tmp_context.time_store) == 0
+
+
+def test_timeit_returns_original_result(tmp_context: context.WorkContext) -> None:
+    result = _test_func(ctx=tmp_context)
+
+    assert result == "ok"
+
+
+def test_timeit_extracts_version_from_return(
+    tmp_context: context.WorkContext,
+) -> None:
+    req = Requirement("mypkg")
+
+    _test_returns_version(ctx=tmp_context, req=req)
+
+    assert "mypkg==1.2.3" in tmp_context.time_store
+
+
+def test_timeit_propagates_exception(tmp_context: context.WorkContext) -> None:
+    with pytest.raises(RuntimeError, match="test error"):
+        _test_raises(ctx=tmp_context)
+
+
+def test_timeit_no_storage_on_exception(tmp_context: context.WorkContext) -> None:
+    req = Requirement("numpy>=1.0")
+
+    with pytest.raises(RuntimeError):
+        _test_raises(ctx=tmp_context, req=req)
+
+    assert len(tmp_context.time_store) == 0
+
+
+def test_summarize_logs_timing(
+    tmp_context: context.WorkContext,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    req = Requirement("numpy>=1.0")
+    _test_func(ctx=tmp_context, req=req, version="1.26.0")
+
+    with caplog.at_level(logging.INFO, logger="fromager.metrics"):
+        metrics.summarize(tmp_context, "Building")
+
+    records = [r for r in caplog.records if r.name == "fromager.metrics"]
+    assert len(records) == 1
+    msg = records[0].message
+    assert "Building" in msg
+    assert "numpy==1.26.0" in msg
+    assert "test description" in msg
+
+
+def test_summarize_empty(
+    tmp_context: context.WorkContext,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    with caplog.at_level(logging.INFO, logger="fromager.metrics"):
+        metrics.summarize(tmp_context, "Building")
+
+    assert len(caplog.records) == 0
+
+
+def test_extract_version_from_tuple() -> None:
+    ret = ("http://example.com", Version("2.0.0"))
+    assert metrics._extract_version_from_return(ret) == Version("2.0.0")
+
+
+def test_extract_version_bare() -> None:
+    ret = Version("3.0.0")
+    assert metrics._extract_version_from_return(ret) == Version("3.0.0")
+
+
+def test_extract_version_no_version_in_iterable() -> None:
+    ret = ("http://example.com", "not-a-version")
+    assert metrics._extract_version_from_return(ret) is None
+
+
+def test_extract_version_non_iterable() -> None:
+    assert metrics._extract_version_from_return(42) is None