tbl: add CT_Tc._move_content_to()

Author: Steve Canny

docx/oxml/table.py

@@ -8,7 +8,7 @@
 
 from . import parse_xml
 from ..exceptions import InvalidSpanError
-from .ns import nsdecls
+from .ns import nsdecls, qn
 from ..shared import Emu, Twips
 from .simpletypes import (
     ST_Merge, ST_TblLayoutType, ST_TblWidth, ST_TwipsMeasure, XsdInt
@@ -254,6 +254,16 @@ def grid_span(self):
             return 1
         return tcPr.grid_span
 
+    def iter_block_items(self):
+        """
+        Generate a reference to each of the block-level content elements in
+        this cell, in the order they appear.
+        """
+        block_item_tags = (qn('w:p'), qn('w:tbl'), qn('w:sdt'))
+        for child in self:
+            if child.tag in block_item_tags:
+                yield child
+
     @property
     def left(self):
         """
@@ -372,16 +382,52 @@ def _insert_tcPr(self, tcPr):
         self.insert(0, tcPr)
         return tcPr
 
+    @property
+    def _is_empty(self):
+        """
+        True if this cell contains only a single empty ``<w:p>`` element.
+        """
+        block_items = list(self.iter_block_items())
+        if len(block_items) > 1:
+            return False
+        p = block_items[0]  # cell must include at least one <w:p> element
+        if len(p.r_lst) == 0:
+            return True
+        return False
+
     def _move_content_to(self, other_tc):
         """
         Append the content of this cell to *other_tc*, leaving this cell with
         a single empty ``<w:p>`` element.
         """
-        raise NotImplementedError
+        if other_tc is self:
+            return
+        if self._is_empty:
+            return
+        other_tc._remove_trailing_empty_p()
+        # appending moves each element from self to other_tc
+        for block_element in self.iter_block_items():
+            other_tc.append(block_element)
+        # add back the required minimum single empty <w:p> element
+        self.append(self._new_p())
 
     def _new_tbl(self):
         return CT_Tbl.new()
 
+    def _remove_trailing_empty_p(self):
+        """
+        Remove the last content element from this cell if it is an empty
+        ``<w:p>`` element.
+        """
+        block_items = list(self.iter_block_items())
+        last_content_elm = block_items[-1]
+        if last_content_elm.tag != qn('w:p'):
+            return
+        p = last_content_elm
+        if len(p.r_lst) > 0:
+            return
+        self.remove(p)
+
     def _span_dimensions(self, other_tc):
         """
         Return a (top, left, height, width) 4-tuple specifying the extents of

tests/oxml/test_table.py

@@ -14,7 +14,7 @@
 from docx.oxml import parse_xml
 from docx.oxml.table import CT_Row, CT_Tc
 
-from ..unitutil.cxml import element
+from ..unitutil.cxml import element, xml
 from ..unitutil.file import snippet_seq
 from ..unitutil.mock import call, instance_mock, method_mock, property_mock
 
@@ -73,6 +73,12 @@ def it_can_extend_its_horz_span_to_help_merge(self, span_width_fixture):
         assert tc._swallow_next_tc.call_args_list == expected_calls
         assert tc.vMerge == vMerge
 
+    def it_can_move_its_content_to_help_merge(self, move_fixture):
+        tc, tc_2, expected_tc_xml, expected_tc_2_xml = move_fixture
+        tc._move_content_to(tc_2)
+        assert tc.xml == expected_tc_xml
+        assert tc_2.xml == expected_tc_2_xml
+
     def it_raises_on_tr_above(self, tr_above_raise_fixture):
         tc = tr_above_raise_fixture
         with pytest.raises(ValueError):
@@ -128,6 +134,27 @@ def merge_fixture(
         tr_.tc_at_grid_col.return_value = top_tc_
         return tc, other_tc, tr_, top_tc_, left, height, width
 
+    @pytest.fixture(params=[
+        ('w:tc/w:p',             'w:tc/w:p',
+         'w:tc/w:p',             'w:tc/w:p'),
+        ('w:tc/w:p',             'w:tc/w:p/w:r',
+         'w:tc/w:p',             'w:tc/w:p/w:r'),
+        ('w:tc/w:p/w:r',         'w:tc/w:p',
+         'w:tc/w:p',             'w:tc/w:p/w:r'),
+        ('w:tc/(w:p/w:r,w:sdt)', 'w:tc/w:p',
+         'w:tc/w:p',             'w:tc/(w:p/w:r,w:sdt)'),
+        ('w:tc/(w:p/w:r,w:sdt)', 'w:tc/(w:tbl,w:p)',
+         'w:tc/w:p',             'w:tc/(w:tbl,w:p/w:r,w:sdt)'),
+    ])
+    def move_fixture(self, request):
+        tc_cxml, tc_2_cxml, expected_tc_cxml, expected_tc_2_cxml = (
+            request.param
+        )
+        tc, tc_2 = element(tc_cxml), element(tc_2_cxml)
+        expected_tc_xml = xml(expected_tc_cxml)
+        expected_tc_2_xml = xml(expected_tc_2_cxml)
+        return tc, tc_2, expected_tc_xml, expected_tc_2_xml
+
     @pytest.fixture(params=[
         (0, 0, 0, 0, 1, (0, 0, 1, 2)),
         (0, 0, 1, 2, 1, (0, 1, 3, 1)),