Add end to end test and improve the train_clas params

tests/test_end_to_end.py

@@ -0,0 +1,47 @@
+import fire
+import pytest
+
+import ulmfit.pretrain_lm
+import ulmfit.train_clas
+from fastai import *
+from fastai.text import *
+from fastai_contrib.utils import  *
+"""
+It is a mixture of a pytest unit test and woven together to compose an end to end functional test. 
+"""
+
+def check_data_exists():
+    data = get_data_folder()
+
+    wt2 = data / "wiki" / "wikitext-2"
+    imdb = data / "imdb"
+    ensure_paths_exists(wt2 / "en.wiki.train.tokens",
+                        imdb / "train.csv",
+                        message="We don't run data preparation scripts automatically as it takes ages, run prepare_wiki-en.sh & prepare_imdb.sh")
+    return imdb, wt2
+
+def test_pretrain_lm():
+    imdb,wt2 = check_data_exists()
+    lm_name="end-to-end-test-quick"
+    results = ulmfit.pretrain_lm.pretrain_lm(
+        dir_path=wt2,
+        lang='en',
+        qrnn=True,
+        clean=True,
+        max_vocab=1000,
+        bs=80,
+        num_epochs=1,
+        name=lm_name,
+        ds_pct=0.03
+    )
+    assert results['accuracy'] > 0.30
+
+    results = ulmfit.train_clas.new_train_clas(
+                data_dir=get_data_folder(),
+                lang='en', pretrain_name=lm_name, model_dir=wt2/'models',
+                qrnn=True,
+                fine_tune=True,
+                max_vocab=1000,
+                bs=20, bptt=70, name=lm_name+'-imdb-clas',
+                dataset='imdb',
+                ds_pct=0.03)