diff --git a/tests/test_jenkins_build_weather.py b/tests/test_jenkins_build_weather.py
index 8b9c0ab..2e3eb5f 100644
--- a/tests/test_jenkins_build_weather.py
+++ b/tests/test_jenkins_build_weather.py
@@ -4,6 +4,7 @@ from datetime import datetime, timezone
 import types
 
 import httpx
+import pytest
 from prometheus_client import REGISTRY
 
 from ariadne.services import jenkins_build_weather as weather_module
@@ -225,3 +226,100 @@ def test_fetch_jobs_flattens_folder_jobs(monkeypatch) -> None:
     assert jobs[0].status == "success"
     assert jobs[0].last_duration_seconds == 1.0
     assert datetime.fromtimestamp(jobs[0].last_run_ts, tz=timezone.utc).year == 2024
+
+
+def test_weather_helper_edges(monkeypatch) -> None:
+    assert weather_module._metric_number(True) == 0.0
+    assert weather_module._metric_number(object()) == 0.0
+    assert weather_module._millis_to_seconds(0) == 0.0
+
+    monkeypatch.setattr(
+        weather_module,
+        "settings",
+        types.SimpleNamespace(jenkins_api_user=" user ", jenkins_api_token=" token "),
+    )
+    assert weather_module._jenkins_auth() == ("user", "token")
+
+    assert weather_module._jenkins_status({"color": "blue_anime"}) == "running"
+    assert weather_module._jenkins_status({"color": "green"}) == "success"
+    assert weather_module._jenkins_status({"color": "yellow"}) == "failure"
+    assert weather_module._jenkins_status({}) == "unknown"
+
+    assert weather_module._health_score({"healthReport": ["bad"]}, "success") == 100.0
+    assert weather_module._health_score({}, "running") == 60.0
+    assert weather_module._health_score({}, "failure") == 10.0
+    assert weather_module._health_score({}, "unknown") == -1.0
+
+    assert weather_module._weather_icon(-1) == "❔"
+    assert weather_module._weather_icon(60) == "⛅"
+    assert weather_module._weather_icon(20) == "🌧️"
+
+
+def test_flatten_parse_and_fetch_edges(monkeypatch) -> None:
+    flattened = weather_module._flatten_jobs(
+        [
+            "bad",
+            {"name": ""},
+            {"name": "folder", "jobs": [{"name": "child", "url": "https://ci/job/child/", "lastBuild": {"result": "SUCCESS"}}]},
+            {"name": "folder-without-build", "jobs": []},
+        ]
+    )
+    assert [job["name"] for job in flattened] == ["folder/child", "folder-without-build"]
+    assert weather_module._parse_job({"name": "missing-url"}) is None
+
+    monkeypatch.setattr(weather_module, "settings", _dummy_settings(base_url=""))
+    assert weather_module._fetch_jobs() == []
+
+    captured = {}
+
+    class CapturingClient(_DummyClient):
+        def __init__(self, **kwargs):
+            captured.update(kwargs)
+            super().__init__({"jobs": [{"name": "bad"}]})
+
+    monkeypatch.setattr(
+        weather_module,
+        "settings",
+        types.SimpleNamespace(
+            jenkins_base_url="https://ci.bstein.dev/",
+            jenkins_api_user="user",
+            jenkins_api_token="token",
+            jenkins_api_timeout_sec=7.0,
+        ),
+    )
+    monkeypatch.setattr(weather_module.httpx, "Client", CapturingClient)
+    assert weather_module._fetch_jobs() == []
+    assert captured["auth"] == ("user", "token")
+    assert captured["timeout"] == 7.0
+
+    class NonObjectClient(_DummyClient):
+        def __init__(self, **kwargs):
+            super().__init__(["bad"])
+
+    monkeypatch.setattr(weather_module.httpx, "Client", NonObjectClient)
+    with pytest.raises(ValueError, match="non-object"):
+        weather_module._fetch_jobs()
+
+
+def test_remove_missing_series_ignores_missing_metric_labels(monkeypatch) -> None:
+    class MissingMetric:
+        def remove(self, *labels):
+            raise KeyError(labels)
+
+    weather_module._JOB_SERIES = {("old", "https://ci/job/old/", "☀️")}
+    monkeypatch.setattr(weather_module, "_JOB_METRICS", (MissingMetric(),))
+
+    weather_module._remove_missing_series(set())
+
+    assert weather_module._JOB_SERIES == set()
+
+
+def test_collect_jenkins_build_weather_records_error(monkeypatch) -> None:
+    monkeypatch.setattr(weather_module, "settings", _dummy_settings())
+    before = _metric_value("ariadne_jenkins_build_weather_runs_total", {"status": "error"}) or 0.0
+    monkeypatch.setattr(weather_module, "_fetch_jobs", lambda: (_ for _ in ()).throw(RuntimeError("jenkins down")))
+
+    with pytest.raises(RuntimeError, match="jenkins down"):
+        weather_module.collect_jenkins_build_weather()
+
+    assert (_metric_value("ariadne_jenkins_build_weather_runs_total", {"status": "error"}) or 0.0) == before + 1