Specialize blocked root boundary mode at compile time

tests/unit/test_refinement_mrt.py

@@ -24,11 +24,14 @@ class RefinementMRTHost(unittest.TestCase):
         """MRT is an additive compile-time branch; SRT statements and other guards remain."""
         blocks = (KERNELS / "blocks.cu").read_text()
         channel = (KERNELS / "step/block_channel.cu").read_text()
+        block_collision = (KERNELS / "operators/block_collision.cuh").read_text()
+        self.assertIn('#include "operators/block_collision.cuh"', blocks)
+        self.assertEqual(blocks.count("block_collide(f);"), 1)
         refinement = (KERNELS / "refinement.cu").read_text()
         for text in ("compute_feq_from_momentum(drho, jx, jy, ux, uy, feq);",
                      "compute_feq(rho, ux, uy, feq);",
                      "collide_srt_no_force(f, feq, d_params.omega);"):
-            self.assertIn(text, blocks)
+            self.assertIn(text, block_collision)
         self.assertIn("collide_srt(f, feq, forcing, omega);", channel)
         self.assertIn("collide_srt_no_force(f, feq, d_params.omega);", refinement)
         for source in (blocks, refinement):
@@ -40,10 +43,11 @@ class RefinementMRTHost(unittest.TestCase):
         # One shared unforced MRT body; each blocked/patch path calls it exactly once.
         mrt = (KERNELS / "operators/collision_mrt.cuh").read_text()
         self.assertEqual(mrt.count("void collide_mrt_unforced("), 1)
-        for source in (blocks, channel, refinement):
+        for source in (blocks + "\n" + block_collision, channel, refinement):
             self.assertEqual(source.count("collide_mrt_unforced(f);"), 1)
             self.assertNotIn("collide_mrt_no_force(", source)
             self.assertNotIn("compute_rho_u(f, rho, ux, uy);\n            collide_mrt", source)
+            self.assertNotRegex(source, r"compute_rho_u\(f, rho, ux, uy\);\s*collide_mrt")
 
 
 if __name__ == "__main__": unittest.main()