--- a
+++ b/tests/tokenizer/test_tokenizer_ons.py
@@ -0,0 +1,55 @@
+from deidentify.tokenizer.tokenizer_ons import TokenizerOns
+
+tokenizer = TokenizerOns()
+
+
+def test_tokenizer():
+    text = '=== Answer: 1234 ===\ntest a b c d.\n=== Report: 1234 ===\nMw. test test test'
+    doc = tokenizer.parse_text(text)
+
+    tokens = [t.text for t in doc]
+
+    assert tokens == [
+        '=== Answer: 1234 ===\n', 'test', 'a', 'b', 'c', 'd.', '\n', '=== Report: 1234 ===\n',
+        'Mw.', 'test', 'test', 'test'
+    ]
+
+
+def test_sentence_segmentation():
+    text = '=== Answer: 1234 ===\nDit is een zin.\n=== Report: 1234 ===\nMw. heeft goed gegeten.'
+    doc = tokenizer.parse_text(text)
+    sents = [sent.text for sent in doc.sents]
+
+    assert sents == [
+        '=== Answer: 1234 ===\n',
+        'Dit is een zin.\n',
+        '=== Report: 1234 ===\n',
+        'Mw. heeft goed gegeten.'
+    ]
+
+    sents = list(doc.sents)
+    assert [token.text for token in sents[0]] == ['=== Answer: 1234 ===\n']
+    assert [token.text for token in sents[1]] == ['Dit', 'is', 'een', 'zin', '.', '\n']
+    assert [token.text for token in sents[2]] == ['=== Report: 1234 ===\n']
+    assert [token.text for token in sents[3]] == ['Mw.', 'heeft', 'goed', 'gegeten', '.']
+
+
+def test_infix_split_on_parenthesis():
+    text = 'GRZ(12-12-2020).'
+    doc = tokenizer.parse_text(text)
+    tokens = [t.text for t in doc]
+    assert tokens == 'GRZ ( 12-12-2020 ) .'.split()
+
+
+def test_infix_split_on_forward_slash():
+    text = 'Groot/Kempers'
+    doc = tokenizer.parse_text(text)
+    tokens = [t.text for t in doc]
+    assert tokens == 'Groot / Kempers'.split()
+
+
+def test_infix_split_on_forward_slash_exclude_dates():
+    text = '13/01/2020'
+    doc = tokenizer.parse_text(text)
+    tokens = [t.text for t in doc]
+    assert tokens == ['13/01/2020']