[No merge] TF integration testing (#7621)

* stash

* TF Integration testing for ELECTRA, BERT, Longformer

* Trigger slow tests

* Apply suggestions from code review

tests/test_modeling_tf_longformer.py

@@ -622,3 +622,25 @@ class TFLongformerModelIntegrationTest(unittest.TestCase):
         tf.debugging.assert_near(tf.reduce_mean(loss), expected_loss, rtol=1e-4)
         tf.debugging.assert_near(tf.reduce_sum(prediction_scores), expected_prediction_scores_sum, rtol=1e-4)
         tf.debugging.assert_near(tf.reduce_mean(prediction_scores), expected_prediction_scores_mean, rtol=1e-4)
+
+    @slow
+    def test_inference_masked_lm(self):
+        model = TFLongformerForMaskedLM.from_pretrained("lysandre/tiny-longformer-random")
+        input_ids = tf.constant([[0, 1, 2, 3, 4, 5]])
+        output = model(input_ids)[0]
+
+        expected_shape = [1, 6, 10]
+        self.assertEqual(output.shape, expected_shape)
+
+        print(output[:, :3, :3])
+
+        expected_slice = tf.constant(
+            [
+                [
+                    [-0.04926379, 0.0367098, 0.02099686],
+                    [0.03940692, 0.01547744, -0.01448723],
+                    [0.03495252, -0.05900355, -0.01675752],
+                ]
+            ]
+        )
+        tf.debugging.assert_near(output[:, :3, :3], expected_slice, atol=1e-4)