🚨🚨 Generate: standardize beam search behavior across frameworks (#21368)

tests/models/bart/test_modeling_flax_bart.py

@@ -426,7 +426,7 @@ class FlaxBartModelTest(FlaxModelTesterMixin, unittest.TestCase, FlaxGenerationT
         )
 
         input_ids = tokenizer(input_str, return_tensors="np").input_ids
-        sequences = model.generate(input_ids, num_beams=2, max_length=20).sequences
+        sequences = model.generate(input_ids, num_beams=2, min_length=None, max_length=20).sequences
 
         output_str = tokenizer.batch_decode(sequences)[0]
 

tests/models/gpt2/test_modeling_flax_gpt2.py

@@ -224,7 +224,7 @@ class FlaxGPT2ModelTest(FlaxModelTesterMixin, FlaxGenerationTesterMixin, unittes
         output_string = tokenizer.batch_decode(output_sequences, skip_special_tokens=True)
 
         expected_string = [
-            "Hello this is a long string of words. I'm going to try to explain what I mean.",
+            "Hello this is a long string of words. I'm going to start with the first one.\n",
             "Hey, I'm not sure if I'm going to be able to do",
         ]
 

tests/models/t5/test_modeling_flax_t5.py

@@ -1076,7 +1076,7 @@ class FlaxT5ModelIntegrationTests(unittest.TestCase):
         expected_summaries = [
             'prosecutor: "so far no videos were used in the crash investigation" two magazines claim to have found a'
             " cell phone video of the final seconds . \"one can hear cries of 'My God' in several languages,\" one"
-            " magazine says . all 150 on board were killed when germanwings flight 9525 crashed .",
+            " magazine says . all 150 on board were killed in the crash .",
             "the formal accession was marked by a ceremony at The Hague, in the Netherlands . the ICC opened a"
             " preliminary examination into the situation in the occupied Palestinian territory . as members of the"
             " court, Palestinians may be subject to counter-charges as well .",