fix and rename helper function to recognize python backends. (#430)

fix the is_otf:

    - recognize backend by backend.__name__
    - invert the negation: it now tests positively for python backends

in addition unskip those tests with embedded that now work, only skip for roundtrip because it is too slow and run the datatests for metric fields with gtfn_cpu .

ci/default.yml

@@ -30,7 +30,8 @@ test_model_datatests:
     extends: .test_template
     stage: test
     script:
-        - tox -r -e run_model_tests -c model/ --verbose -- $COMPONENT
+        - tox -r -e run_model_tests -c model/ --verbose -- --backend=$BACKEND $COMPONENT
     parallel:
         matrix:
             - COMPONENT: [atmosphere/diffusion/tests/diffusion_tests, atmosphere/dycore/tests/dycore_tests, common/tests, driver/tests]
+              BACKEND: [gtfn_cpu]

model/common/src/icon4py/model/common/test_utils/helpers.py

@@ -14,7 +14,6 @@
 from dataclasses import dataclass, field
 from typing import ClassVar, Optional
 
-import gt4py.next.program_processors.modular_executor
 import numpy as np
 import numpy.typing as npt
 import pytest
@@ -37,16 +36,19 @@ def backend(request):
     return request.param
 
 
-def is_otf(backend) -> bool:
+def is_python(backend) -> bool:
     # want to exclude python backends:
     #   - cannot run on embedded: because of slicing
     #   - roundtrip is very slow on large grid
-    if hasattr(backend, "executor"):
-        if isinstance(
-            backend.executor, gt4py.next.program_processors.modular_executor.ModularExecutor
-        ):
-            return True
-    return False
+    return is_embedded(backend) or is_roundtrip(backend)
+
+
+def is_embedded(backend) -> bool:
+    return backend is None
+
+
+def is_roundtrip(backend) -> bool:
+    return backend.__name__ == "roundtrip" if backend else False
 
 
 def _shape(

model/common/tests/metric_tests/test_metric_fields.py

@@ -25,7 +25,8 @@
 from icon4py.model.common.test_utils.helpers import (
     StencilTest,
     dallclose,
-    is_otf,
+    is_python,
+    is_roundtrip,
     random_field,
     zero_field,
 )
@@ -65,7 +66,7 @@ def input_data(self, grid) -> dict:
 
 
 def test_compute_ddq_z_half(icon_grid, metrics_savepoint, backend):
-    if not is_otf(backend):
+    if is_python(backend):
         pytest.skip("skipping: unsupported backend")
     ddq_z_half_ref = metrics_savepoint.ddqz_z_half()
     z_ifc = metrics_savepoint.z_ifc()
@@ -100,8 +101,8 @@ def test_compute_ddq_z_half(icon_grid, metrics_savepoint, backend):
 
 
 def test_compute_ddqz_z_full(icon_grid, metrics_savepoint, backend):
-    if not is_otf(backend):
-        pytest.skip("skipping: unsupported backend")
+    if is_roundtrip(backend):
+        pytest.skip("skipping: slow backend")
     z_ifc = metrics_savepoint.z_ifc()
     inv_ddqz_full_ref = metrics_savepoint.inv_ddqz_z_full()
     ddqz_z_full = zero_field(icon_grid, CellDim, KDim)

model/common/tests/metric_tests/test_reference_atmosphere.py

@@ -26,7 +26,7 @@
     compute_reference_atmosphere_cell_fields,
     compute_reference_atmosphere_edge_fields,
 )
-from icon4py.model.common.test_utils.helpers import dallclose, is_otf, zero_field
+from icon4py.model.common.test_utils.helpers import dallclose, is_roundtrip, zero_field
 from icon4py.model.common.type_alias import wpfloat
 
 
@@ -38,6 +38,8 @@
 def test_compute_reference_atmosphere_fields_on_full_level_masspoints(
     icon_grid, metrics_savepoint, backend
 ):
+    if is_roundtrip(backend):
+        pytest.skip("skipping: slow backend")
     exner_ref_mc_ref = metrics_savepoint.exner_ref_mc()
     rho_ref_mc_ref = metrics_savepoint.rho_ref_mc()
     theta_ref_mc_ref = metrics_savepoint.theta_ref_mc()
@@ -89,6 +91,8 @@ def test_compute_reference_atmosphere_fields_on_full_level_masspoints(
 def test_compute_reference_atmsophere_on_half_level_mass_points(
     icon_grid, metrics_savepoint, backend
 ):
+    if is_roundtrip(backend):
+        pytest.skip("skipping: slow backend")
     theta_ref_ic_ref = metrics_savepoint.theta_ref_ic()
     z_ifc = metrics_savepoint.z_ifc()
 
@@ -124,8 +128,8 @@ def test_compute_reference_atmsophere_on_half_level_mass_points(
 
 @pytest.mark.datatest
 def test_compute_d_exner_dz_ref_ic(icon_grid, metrics_savepoint, backend):
-    if not is_otf(backend):
-        pytest.skip("skipping: unsupported backend")
+    if is_roundtrip(backend):
+        pytest.skip("skipping: slow backend")
     theta_ref_ic = metrics_savepoint.theta_ref_ic()
     d_exner_dz_ref_ic_ref = metrics_savepoint.d_exner_dz_ref_ic()
     d_exner_dz_ref_ic = zero_field(icon_grid, CellDim, KDim, extend={KDim: 1})
@@ -144,8 +148,8 @@ def test_compute_d_exner_dz_ref_ic(icon_grid, metrics_savepoint, backend):
 def test_compute_reference_atmosphere_on_full_level_edge_fields(
     icon_grid, interpolation_savepoint, metrics_savepoint, backend
 ):
-    if not is_otf(backend):
-        pytest.skip("skipping: unsupported backend")
+    if is_roundtrip(backend):
+        pytest.skip("skipping: slow backend")
     rho_ref_me_ref = metrics_savepoint.rho_ref_me()
     theta_ref_me_ref = metrics_savepoint.theta_ref_me()
     rho_ref_me = metrics_savepoint.rho_ref_me()