feat: add review effort accounting and budget governor

tests/pilot/review_tests/budget_test.py

@@ -0,0 +1,49 @@
+"""Budget policy and accounting tests."""
+
+import os
+import sys
+import json
+
+ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", ".."))
+sys.path.insert(0, os.path.join(ROOT, "pilot"))
+
+from review.budget import Budget, BudgetState  # noqa: E402
+from review import opencode_runtime  # noqa: E402
+from review.opencode import parse_opencode_events  # noqa: E402
+
+
+def test_budget_reads_config_over_environment(monkeypatch):
+    monkeypatch.setenv("PRAGENT_MAX_REVIEW_STEPS", "3")
+    budget = Budget.from_config({"budget": {"max_steps": 7}})
+    assert budget.max_steps == 7
+
+
+def test_budget_state_stops_at_token_limit():
+    state = BudgetState(Budget(max_steps=20, max_total_tokens=100))
+    assert state.record({"steps": 1, "total": 60, "output": 10}) == ""
+    assert state.record({"steps": 1, "total": 40, "output": 10}) == "max_total_tokens"
+    assert state.snapshot()["cap_hit"] is True
+
+
+def test_budget_state_tracks_cost_cap():
+    state = BudgetState(Budget(max_equivalent_cost_usd=1.0))
+    assert state.record({"steps": 1, "total": 1}, 0.75) == ""
+    assert state.record({"steps": 1, "total": 1}, 0.25) == "max_equivalent_cost_usd"
+
+
+def test_process_terminates_after_step_budget():
+    code = (
+        "import json,time; "
+        "print(json.dumps({'type':'step_finish','part':{'tokens':{"
+        "'input':1,'output':1,'total':2}}}), flush=True); "
+        "time.sleep(30)"
+    )
+    budget = Budget(max_steps=1, max_duration_seconds=10)
+    state = BudgetState(budget)
+    proc = opencode_runtime._run_process(
+        [sys.executable, "-u", "-c", code], cwd=".", env=os.environ.copy(),
+        timeout=10, parse_events=parse_opencode_events, budget=budget,
+        budget_state=state, model="glm-5.2:cloud", runner=None,
+    )
+    assert state.snapshot()["cap_reason"] == "max_steps"
+    assert proc.stdout.count("step_finish") == 1