fix(tests): correct slow-tests expected texts for do_sample=True

Add the top_k filtering to increase variability when doing tests with
do_sample.

text-generation-inference/tests/test_decode.py

@@ -1,4 +1,3 @@
-
 from dataclasses import dataclass
 
 import pytest
@@ -17,6 +16,7 @@ class DecodeTestParams:
     expected_text: str
     do_sample: bool = False
     max_new_tokens: int = 20
+    top_k: int = 50
 
 
 @pytest.mark.parametrize("params",
@@ -70,7 +70,13 @@ def _test_decode_single(params):
     generator = AutoGenerator.from_pretrained(
         model_path, revision="", max_batch_size=1, max_sequence_length=params.sequence_length
     )
-    request = create_request(id=0, inputs=input_text, max_new_tokens=max_new_tokens, do_sample=params.do_sample)
+    request = create_request(
+        id=0,
+        inputs=input_text,
+        max_new_tokens=max_new_tokens,
+        do_sample=params.do_sample,
+        top_k=params.top_k,
+    )
     batch = Batch(id=0, requests=[request], size=1, max_tokens=params.sequence_length)
     generations, next_batch = generator.prefill(batch)
     # We already generated one token: call decode max_new_tokens - 1 times
@@ -88,6 +94,7 @@ def _test_decode_single(params):
     output = generations[0].generated_text
     assert output.generated_tokens == max_new_tokens
     assert output.finish_reason == 0
+    print(f"Generated text: {output.text}")
     if params.do_sample:
         assert output.text != params.expected_text
     else:
@@ -102,11 +109,13 @@ def _test_decode_single(params):
             model_id="meta-llama/Llama-2-7b-hf",
             sequence_length=256,
             expected_text="\nWinston Smith, his chin nuzzled into his breast in an effort to escape",
+            top_k=100,
         ),
         DecodeTestParams(
             model_id="meta-llama/Meta-Llama-3-8B",
             sequence_length=256,
             expected_text=" Winston Smith, his chin nuzzled into his breast in an effort to escape the vile wind,",
+            top_k=100,
         ),
     ],
     ids=["Llama-2-7b-hf", "Meta-Llama-3-8B"],