Test Word equation segmentation

tests/test_math_format.py

@@ -1,6 +1,6 @@
 import pytest
 
-from ai_typewriter.math_format import format_math_text
+from ai_typewriter.math_format import format_math_text, split_word_equation_segments
 
 
 def test_plain_mode_keeps_linear_math_literal():
@@ -19,6 +19,18 @@ def test_unicode_mode_converts_common_operators():
     assert result == "∫₀¹ f(x) dx ≤ ∑ₖ₌₁ⁿ aₖ"
 
 
+def test_word_equation_segments_keep_word_unicodemath_syntax():
+    segments = split_word_equation_segments(r"On pose z_1 = x + iy. Puis \alpha = 2.")
+
+    assert [(segment.kind, segment.value) for segment in segments] == [
+        ("text", "On pose "),
+        ("equation", "z_1 = x + iy"),
+        ("text", ". Puis "),
+        ("equation", r"\alpha = 2"),
+        ("text", "."),
+    ]
+
+
 def test_invalid_math_text_format_is_rejected():
     with pytest.raises(ValueError):
         format_math_text("x_1", "bad")