Flax testing should not run the full torch test suite (#10725)

* make flax tests pytorch independent

* fix typo

* finish

* improve circle ci

* fix return tensors

* correct flax test

* re-add sentencepiece

* last tokenizer fixes

* finish maybe now

tests/test_modeling_flax_common.py

@@ -19,7 +19,7 @@ import numpy as np
 
 import transformers
 from transformers import is_flax_available, is_torch_available
-from transformers.testing_utils import require_flax, require_torch
+from transformers.testing_utils import is_pt_flax_cross_test, require_flax
 
 
 if is_flax_available():
@@ -60,7 +60,6 @@ def random_attention_mask(shape, rng=None):
     return attn_mask
 
 
-@require_flax
 class FlaxModelTesterMixin:
     model_tester = None
     all_model_classes = ()
@@ -69,7 +68,7 @@ class FlaxModelTesterMixin:
         diff = np.abs((a - b)).max()
         self.assertLessEqual(diff, tol, f"Difference between torch and flax is {diff} (>= {tol}).")
 
-    @require_torch
+    @is_pt_flax_cross_test
     def test_equivalence_flax_pytorch(self):
         config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()
 
@@ -104,6 +103,7 @@ class FlaxModelTesterMixin:
                 for fx_output_loaded, pt_output in zip(fx_outputs_loaded, pt_outputs):
                     self.assert_almost_equals(fx_output_loaded, pt_output.numpy(), 5e-3)
 
+    @require_flax
     def test_from_pretrained_save_pretrained(self):
         config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()
 
@@ -121,6 +121,7 @@ class FlaxModelTesterMixin:
                 for output_loaded, output in zip(outputs_loaded, outputs):
                     self.assert_almost_equals(output_loaded, output, 5e-3)
 
+    @require_flax
     def test_jit_compilation(self):
         config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()
 
@@ -143,6 +144,7 @@ class FlaxModelTesterMixin:
                 for jitted_output, output in zip(jitted_outputs, outputs):
                     self.assertEqual(jitted_output.shape, output.shape)
 
+    @require_flax
     def test_naming_convention(self):
         for model_class in self.all_model_classes:
             model_class_name = model_class.__name__