导出test_mql活塞运动学

tests/test_test_mql_mechanical.py

@@ -120,6 +120,30 @@ class TestMqlMechanicalAssemblyTests(unittest.TestCase):
         self.assertAlmostEqual(rear.velocities_m_s[1], -0.3)
         self.assertAlmostEqual(rear.displacements_m[8], -0.72)
 
+    def test_mechanical_mass_snapshot_exposes_piston_kinematics(self) -> None:
+        closure = TestMqlMechanicalMassClosure(self.assembly)
+        state = closure.initial_state_vector()
+        state[0] = 0.4
+        state[1] = 0.37
+        state[18] = -0.3
+        state[19] = -0.72
+
+        snapshot = closure.snapshot(state)
+        piston = snapshot.piston_kinematics_by_alias["pn_brp2_8"]
+
+        self.assertEqual(set(snapshot.piston_kinematics_by_alias), set(self.assembly.pistons))
+        self.assertAlmostEqual(piston.port_2_velocity_m_s, 0.4)
+        self.assertAlmostEqual(piston.port_2_displacement_m, 0.37)
+        self.assertAlmostEqual(piston.port_3_velocity_m_s, -0.3)
+        self.assertAlmostEqual(piston.port_3_displacement_m, -0.72)
+        self.assertAlmostEqual(
+            self.assembly.pistons["pn_brp2_8"].geometry().chamber_length_mm(
+                piston.port_3_displacement_m,
+                piston.port_2_displacement_m,
+            ),
+            1090.0,
+        )
+
     def test_system_simulates_mechanical_mass_state_closure(self) -> None:
         system = TestMqlSystem()