fix gpu target check in lbstep. Re-enable gpu tests.

src/lbmpy/lbstep.py

@@ -47,8 +47,10 @@ class LatticeBoltzmannStep:
         if config is not None:
             if IS_PYSTENCILS_2:
                 target = config.get_target()
+                is_gpu = target.is_gpu()
             else:
                 target = config.target
+                is_gpu = target == Target.GPU
         else:
             target = optimization.get('target', Target.CPU)
 
@@ -91,7 +93,7 @@ class LatticeBoltzmannStep:
         self.density_data_name = name + "_density" if density_data_name is None else density_data_name
         self.density_data_index = density_data_index
 
-        self._gpu = target == Target.GPU
+        self._gpu = is_gpu
         layout = lbm_optimisation.field_layout
 
         alignment = False

tests/test_cpu_gpu_equivalence.py

@@ -53,7 +53,9 @@ def test_force_driven_channel_short(scenario):
         config = CreateKernelConfig(gpu_indexing_params={'block_size': block_size})
     else:
         if IS_PYSTENCILS_2:
-            pytest.xfail("Line indexing not available yet")
-        config = CreateKernelConfig(gpu_indexing='line')
+            config = CreateKernelConfig()
+            config.gpu.indexing_scheme = "blockwise4d"
+        else:
+            config = CreateKernelConfig(gpu_indexing='line')
 
     run_equivalence_test(domain_size=ds, lbm_config=lbm_config, lbm_opt=lbm_opt, base_config=config)