Add tests for more stemmers

tests/test_stem.py

@@ -0,0 +1,31 @@
+from whoosh.lang.snowball.english import EnglishStemmer
+from whoosh.lang.snowball.french import FrenchStemmer
+from whoosh.lang.snowball.finnish import FinnishStemmer
+from whoosh.lang.snowball.spanish import SpanishStemmer
+
+
+def test_english():
+    s = EnglishStemmer()
+    assert s.stem("hello") == "hello"
+    assert s.stem("atlas") == "atlas"
+    assert s.stem("stars") == "star"
+
+
+def test_french():
+    s = FrenchStemmer()
+    assert s.stem("adresse") == "adress"
+    assert s.stem("lettres") == "lettr"
+
+
+def test_finnish():
+    s = FinnishStemmer()
+    assert s.stem("valitse") == "valits"
+    assert s.stem("koko") == "koko"
+    assert s.stem("erikoismerkit") == "erikoismerk"
+
+
+def test_spanish_spell_suffix():
+    word = 'tgue'
+    s = SpanishStemmer()
+    w = s.stem(word)
+    assert w == "tgu"