test: add cylinder-free control for bounded SRT inlet diagnosis

tests/validation/uniform_srt_diagnostic/test_diagnostic.py

@@ -94,6 +94,38 @@ def test_source_guard_and_deadline():
     with unittest.TestCase().assertRaises(TimeoutError): d.deadline_check(0)
 
 
+def test_bodyless_selection_preserves_baseline():
+    from copy import deepcopy
+    baseline_config, baseline_body, baseline_parameters = deepcopy((cfg,body,p))
+    selected = d.select_body(body,True)
+    assert selected == {"objects": []}
+    assert (cfg,body,p) == (baseline_config,baseline_body,baseline_parameters)
+    assert d.select_body(body) == baseline_body
+    assert d.select_body(body) is not body
+    assert p['nx']==1761 and p['ny']==330 and p['mean_speed']==.01
+    assert np.isclose(3*p['viscosity']+.5,.524)
+    for invalid in ({"objects":[]},{"objects":body['objects']*2},
+                    {"objects":[{"type":"other"}]}):
+        with unittest.TestCase().assertRaises(ValueError): d.select_body(invalid,True)
+
+
+def test_absent_force_is_not_zero_or_read():
+    class FakeSimulation:
+        def __init__(self): self.calls=[]
+        def read_force(self,index):
+            self.calls.append(index)
+            return np.array([1.,2.],np.float32)
+    sim=FakeSimulation()
+    assert d.body_force(sim,{"objects":[]}) is None and not sim.calls
+    np.testing.assert_array_equal(d.body_force(sim,body),[1.,2.])
+    assert sim.calls==[0]
+    g,m,f,params=fixture()
+    report=d.diagnose(g,m,None,f,params,1)
+    assert report['force'] is None and not report['force_nonfinite']
+    m['ux'][3,1]=.2
+    assert d.diagnose(g,m,None,f,params,2)['physical_failure']
+
+
 if __name__=='__main__':
     result=unittest.TextTestRunner(verbosity=2).run(unittest.TestSuite(
         unittest.FunctionTestCase(fn) for name,fn in sorted(globals().items()) if name.startswith('test_')))