add functional test

Signed-off-by: Yuki Huang <yukih@nvidia.com>

Author: yuki-97

tests/functional/grpo_topp_topk.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd)
+PROJECT_ROOT=$(realpath $SCRIPT_DIR/../..)
+# Mark the current repo as safe, since wandb fetches metadata about the repo
+git config --global --add safe.directory $PROJECT_ROOT
+
+set -eou pipefail
+
+EXP_NAME=$(basename $0 .sh)
+EXP_DIR=$SCRIPT_DIR/$EXP_NAME
+LOG_DIR=$EXP_DIR/logs
+JSON_METRICS=$EXP_DIR/metrics.json
+RUN_LOG=$EXP_DIR/run.log
+export PYTHONPATH=${PROJECT_ROOT}:${PYTHONPATH:-}
+
+rm -rf $EXP_DIR $LOG_DIR
+mkdir -p $EXP_DIR $LOG_DIR
+
+cd $PROJECT_ROOT
+uv run coverage run -a --data-file=$PROJECT_ROOT/tests/.coverage --source=$PROJECT_ROOT/nemo_rl \
+    $PROJECT_ROOT/examples/run_grpo.py \
+    policy.model_name=Qwen/Qwen3-0.6B \
+    grpo.num_prompts_per_step=2 \
+    grpo.num_generations_per_prompt=4 \
+    policy.train_global_batch_size=4 \
+    policy.train_micro_batch_size=1 \
+    policy.generation.temperature=0.8 \
+    policy.generation.top_p=0.9 \
+    policy.generation.top_k=50 \
+    cluster.gpus_per_node=2 \
+    grpo.max_num_steps=2 \
+    logger.tensorboard_enabled=true \
+    logger.log_dir=$LOG_DIR \
+    logger.wandb_enabled=false \
+    logger.monitor_gpus=true \
+    checkpointing.enabled=false \
+    $@ \
+    2>&1 | tee $RUN_LOG
+
+uv run tests/json_dump_tb_logs.py $LOG_DIR --output_path $JSON_METRICS
+
+uv run tests/check_metrics.py $JSON_METRICS \
+    'max(data["train/token_mult_prob_error"]) < 1.05' \
+    'max(data["train/gen_kl_error"]) < 0.03' \
+    'min(data["train/probs_ratio_clamped_min"]) > 0.79' \
+    'max(data["train/probs_ratio_clamped_min"]) < 1.21' \
+    'min(data["train/probs_ratio_clamped_max"]) > 0.79' \
+    'max(data["train/probs_ratio_clamped_max"]) < 1.21'