fix(vision): NaN/inf/bool di uno strumento non diventano più una quota (#16)

runner.run_graph esclude bool e NaN/inf dagli output numerici, con il
motivo in RunOutcome.invalid_outputs. vision_service tratta una quota
mappata con valore None/assente/non finito come "non prodotta" (422),
invece di arrivare a float(None) e sollevare TypeError.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/vision/tests/test_runner.py

@@ -72,6 +72,53 @@ def test_a_broken_tool_does_not_sink_the_others():
     assert any(key.endswith(".diameter") for key in outcome.outputs)
 
 
+class _FakeResult:
+    """Stands in for a vs-task tool result: only what run_graph touches."""
+
+    def __init__(self, tool_id, tool_name, ok, outputs=None, error=None):
+        self.tool_id = tool_id
+        self.tool_name = tool_name
+        self.ok = ok
+        self.outputs = outputs or {}
+        self.error = error
+
+
+def test_a_nan_output_is_dropped_not_measured(monkeypatch):
+    """vs-measure emits NaN on an empty slice (caliper.py:112 per the
+    revisione) - a NaN must not become a quote's value (#16)."""
+    def fake_run(self, context=None):
+        return [_FakeResult("t1", "diametro", True, outputs={"diameter": float("nan")})]
+    monkeypatch.setattr(runner.Task, "run", fake_run)
+
+    outcome = run_graph(a_disc(), a_circle_graph())
+
+    assert outcome.outputs == {}
+    assert outcome.invalid_outputs == {"t1.diameter": "nan"}
+
+
+def test_an_infinite_output_is_dropped_not_measured(monkeypatch):
+    def fake_run(self, context=None):
+        return [_FakeResult("t1", "diametro", True, outputs={"diameter": float("inf")})]
+    monkeypatch.setattr(runner.Task, "run", fake_run)
+
+    outcome = run_graph(a_disc(), a_circle_graph())
+
+    assert outcome.outputs == {}
+    assert outcome.invalid_outputs == {"t1.diameter": "infinite"}
+
+
+def test_a_bool_output_is_not_treated_as_a_measurable_number(monkeypatch):
+    """bool is a subclass of int - a flag output must not become a quote."""
+    def fake_run(self, context=None):
+        return [_FakeResult("t1", "flag", True, outputs={"present": True})]
+    monkeypatch.setattr(runner.Task, "run", fake_run)
+
+    outcome = run_graph(a_disc(), a_circle_graph())
+
+    assert outcome.outputs == {}
+    assert outcome.invalid_outputs == {}
+
+
 def test_the_engine_says_which_version_it_is():
     version = engine_version()
     assert len(version) == 40  # a full git SHA