diff --git a/extracted_text_test.py b/extracted_text_test.py
index 4919a76..890b045 100644
--- a/extracted_text_test.py
+++ b/extracted_text_test.py
@@ -1,6 +1,8 @@
 import unicodedata
 import pytest
 from extracted_text import ExtractedText, ExtractedTextSegment
+from uniseg.graphemecluster import grapheme_clusters
+from qurator.dinglehopper import seq_align
 
 
 def test_text():
@@ -20,3 +22,33 @@ def test_normalization_check():
     with pytest.raises(ValueError, match=r'.*is not normalized.*'):
         ExtractedTextSegment('foo', unicodedata.normalize('NFD', 'Schlyñ'))
     assert ExtractedTextSegment('foo', unicodedata.normalize('NFC', 'Schlyñ'))
+
+
+def test_align():
+    """
+    Test aligning by character while retaining segment id info
+
+    The difficulty here is that aligning should work on grapheme clusters,
+    not Python characters.
+    """
+
+    test1 = ExtractedText([
+        ExtractedTextSegment('s0', 'foo'),
+        ExtractedTextSegment('s1', 'bar'),
+        ExtractedTextSegment('s2', 'bazinga')
+    ], ' ')
+    test2 = ExtractedText([
+        ExtractedTextSegment('x0', 'foo'),
+        ExtractedTextSegment('x1', 'bar'),
+        ExtractedTextSegment('x2', '.'),  # extra .
+        ExtractedTextSegment('x2', 'bazim̃ga'),  # different grapheme cluster, m̃ also is two Python characters
+    ], ' ')
+
+    left_pos = 0; right_pos = 0
+    for left, right in seq_align(grapheme_clusters(test1.text), grapheme_clusters(test2.text)):
+        print(left, right, test1.segment_id_for_pos(left_pos), test2.segment_id_for_pos(right_pos))
+        if left is not None:
+            left_pos += len(left)
+        if right is not None:
+            right_pos += len(right)
+    assert False