Add comprehensive test for OMML fraction fPr fix

Co-authored-by: cau-git <60343111+cau-git@users.noreply.github.com>

tests/test_omml_fraction_fix.py

@@ -0,0 +1,148 @@
+"""
+Test for OMML fraction processing with missing fPr elements
+"""
+
+import lxml.etree as ET
+from docling.backend.docx.latex.omml import oMath2Latex, OMML_NS
+
+
+def test_omml_fraction_missing_fpr():
+    """Test that fractions with missing fPr elements are handled gracefully"""
+    
+    # Create an OMML fraction without fPr element (this would cause KeyError before fix)
+    omml_xml = f'''
+    <math:oMath xmlns:math="{OMML_NS[1:-1]}">
+        <math:f>
+            <math:num>
+                <math:r>
+                    <math:t>a</math:t>
+                </math:r>
+            </math:num>
+            <math:den>
+                <math:r>
+                    <math:t>b</math:t>
+                </math:r>
+            </math:den>
+        </math:f>
+    </math:oMath>
+    '''
+    
+    # Parse and process the OMML - this should not raise KeyError
+    root = ET.fromstring(omml_xml)
+    result = oMath2Latex(root)
+    latex_result = str(result)
+    
+    # Should produce default fraction formatting
+    assert "\\frac{a}{b}" in latex_result
+
+
+def test_omml_fraction_with_fpr():
+    """Test that fractions with fPr elements still work correctly"""
+    
+    # Create an OMML fraction with fPr element
+    omml_xml = f'''
+    <math:oMath xmlns:math="{OMML_NS[1:-1]}">
+        <math:f>
+            <math:fPr>
+                <math:type math:val="bar"/>
+            </math:fPr>
+            <math:num>
+                <math:r>
+                    <math:t>x</math:t>
+                </math:r>
+            </math:num>
+            <math:den>
+                <math:r>
+                    <math:t>y</math:t>
+                </math:r>
+            </math:den>
+        </math:f>
+    </math:oMath>
+    '''
+    
+    # Parse and process the OMML
+    root = ET.fromstring(omml_xml)
+    result = oMath2Latex(root)
+    latex_result = str(result)
+    
+    # Should produce fraction formatting with fPr properties
+    assert "\\frac{x}{y}" in latex_result
+
+
+def test_omml_fraction_missing_components():
+    """Test that fractions with missing numerator or denominator use placeholders"""
+    
+    # Create an OMML fraction with missing numerator
+    omml_xml_missing_num = f'''
+    <math:oMath xmlns:math="{OMML_NS[1:-1]}">
+        <math:f>
+            <math:den>
+                <math:r>
+                    <math:t>b</math:t>
+                </math:r>
+            </math:den>
+        </math:f>
+    </math:oMath>
+    '''
+    
+    # Parse and process the OMML
+    root = ET.fromstring(omml_xml_missing_num)
+    result = oMath2Latex(root)
+    latex_result = str(result)
+    
+    # Should use placeholder for missing numerator
+    assert "formula_skipped" in latex_result
+    assert "b" in latex_result
+
+
+def test_omml_complex_equation_with_missing_fpr():
+    """Test that complex equations with missing fPr continue processing"""
+    
+    # Create a complex equation with a fraction missing fPr
+    omml_xml = f'''
+    <math:oMath xmlns:math="{OMML_NS[1:-1]}">
+        <math:r>
+            <math:t>x = </math:t>
+        </math:r>
+        <math:f>
+            <math:num>
+                <math:r>
+                    <math:t>a + b</math:t>
+                </math:r>
+            </math:num>
+            <math:den>
+                <math:r>
+                    <math:t>c</math:t>
+                </math:r>
+            </math:den>
+        </math:f>
+        <math:r>
+            <math:t> + y</math:t>
+        </math:r>
+    </math:oMath>
+    '''
+    
+    # Parse and process the OMML
+    root = ET.fromstring(omml_xml)
+    result = oMath2Latex(root)
+    latex_result = str(result)
+    
+    # Should process the entire equation correctly
+    assert "x =" in latex_result
+    assert "\\frac{a + b}{c}" in latex_result
+    assert "+ y" in latex_result
+
+
+if __name__ == "__main__":
+    import logging
+    
+    # Set up logging to capture warnings
+    logging.basicConfig(level=logging.WARNING)
+    
+    # Run all tests
+    test_omml_fraction_missing_fpr()
+    test_omml_fraction_with_fpr()
+    test_omml_fraction_missing_components()
+    test_omml_complex_equation_with_missing_fpr()
+    
+    print("All OMML fraction tests passed!")