优化仿真求解性能并修复流量闭合问题（初版）

tests/test_high_stiffness_explicit_rk45.py

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+from __future__ import annotations
+
+import hashlib
+import math
+from pathlib import Path
+import unittest
+
+from app.main import run_system_xml_simulation
+
+
+FIXTURE_PATH = (
+    Path(__file__).resolve().parent
+    / "fixtures"
+    / "high_stiffness_explicit_rk45.xml"
+)
+ORIGINAL_XML_SHA256 = (
+    "27048a99da0a21922d75785b760c3b5d04be3349b8aef6fbfedfd811d87ef1d5"
+)
+
+
+def short_explicit_rk45_xml() -> bytes:
+    original = FIXTURE_PATH.read_bytes()
+    canonical = original.replace(b"\r\n", b"\n").rstrip(b"\n")
+    if hashlib.sha256(canonical).hexdigest() != ORIGINAL_XML_SHA256:
+        raise AssertionError("The high-stiffness RK45 fixture differs from the user XML.")
+    if original.count(b'tStop="10"') != 1:
+        raise AssertionError("Expected one original simulation stop time.")
+    if original.count(b'sampleStep="0.02"') != 1:
+        raise AssertionError("Expected one original simulation sample step.")
+    return original.replace(
+        b'tStop="10"',
+        b'tStop="0.005"',
+        1,
+    ).replace(
+        b'sampleStep="0.02"',
+        b'sampleStep="0.001"',
+        1,
+    )
+
+
+class HighStiffnessExplicitRk45RegressionTests(unittest.TestCase):
+    def test_short_user_model_crosses_the_early_stiff_limit_event(self) -> None:
+        result = run_system_xml_simulation(
+            short_explicit_rk45_xml(),
+            cancel_check=lambda: False,
+        )
+
+        self.assertTrue(result["success"], result["message"])
+        self.assertEqual(result["status"], "completed")
+        self.assertFalse(result["partial"])
+        self.assertEqual(result["simulatedUntil"], 0.005)
+        self.assertNotIn("provided bounds", result["message"])
+
+        integration = result["diagnostics"]["integration"]
+        totals = integration["totals"]
+        self.assertEqual(integration["method"], "RK45")
+        self.assertGreaterEqual(totals["stateTransitionCount"], 1)
+        self.assertGreaterEqual(totals["solverStartCount"], 2)
+
+        series = result["series"]
+        times = series["time"]
+        self.assertEqual(times[0], 0.0)
+        self.assertEqual(times[-1], 0.005)
+        self.assertTrue(
+            all(first < second for first, second in zip(times, times[1:]))
+        )
+        self.assertTrue(any(0.0 < time < 0.001 for time in times))
+        for values in series.values():
+            self.assertEqual(len(values), len(times))
+            self.assertTrue(all(math.isfinite(value) for value in values))
+
+
+if __name__ == "__main__":
+    unittest.main()