From 82b34fc53a1be52da8e60b338f1cf7ee2c655695 Mon Sep 17 00:00:00 2001
From: Mathis Lacombe <81530082+Mathos34@users.noreply.github.com>
Date: Fri, 5 Jun 2026 11:32:46 +0200
Subject: [PATCH] fix(engine): lazy import of tqdm so the test path stays
 import-free

`src/engine.py` previously imported tqdm at module level. As a side
effect, any caller that wanted only `distillation_loss`,
`benchmark_latency`, or `evaluate` (the three functions exercised by
`tests/`) was forced to install tqdm just to load the module.

Move `from tqdm import tqdm` inside `train_one_epoch`, the only
function that actually uses it. Behavior at training time is
unchanged.

This unblocks the CI workflow PR #3, whose lightweight pytest install
deliberately omits tqdm. Same pattern as the spoken-digits-asr lazy
torchaudio fix (PR #4 there).
---
 src/engine.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/engine.py b/src/engine.py
index 565a35e..e7d75d5 100644
--- a/src/engine.py
+++ b/src/engine.py
@@ -7,10 +7,14 @@
 import torch.nn as nn
 import torch.nn.functional as F
 from torch.utils.data import DataLoader
-from tqdm import tqdm
 
 
 def train_one_epoch(model, loader: DataLoader, opt, loss_fn=None) -> float:
+    """Standard training epoch. tqdm is imported lazily so that callers that
+    only need `distillation_loss` or `benchmark_latency` (e.g. the unit-test
+    path) do not pay the tqdm install cost."""
+    from tqdm import tqdm  # noqa: PLC0415
+
     model.train()
     if loss_fn is None:
         loss_fn = nn.CrossEntropyLoss()