Fix package dependency propagation in tables (#371)

Fix #331 by flattening the tree
and adding the packages of all descendants.

Author: neoglez

pylatex/table.py

@@ -242,7 +242,14 @@ def add_row(self, *cells, color=None, escape=None, mapper=None, strict=True):
             escape = self.escape
 
         # Propagate packages used in cells
-        for c in cells:
+        def flatten(x):
+            if _is_iterable(x):
+                return [a for i in x for a in flatten(i)]
+            else:
+                return [x]
+        
+        flat_list = [c for c in cells] + flatten(cells)
+        for c in flat_list:
             if isinstance(c, LatexObject):
                 for p in c.packages:
                     self.packages.add(p)

tests/test_tabular.py

@@ -0,0 +1,69 @@
+#!/usr/bin/env python
+
+from pylatex import Document, Section, Tabular, MultiColumn, StandAloneGraphic
+
+# This file contains function that test several Tabular related functionality.
+
+def test_tabular_can_add_row_passing_many_arguments(sample_logo_path):
+    """
+    Test that Tabular can add a row as described in the function body:
+    The first method is to pass the content of each cell as a separate argument. 
+
+    Returns
+    -------
+    None.
+
+    """
+    doc = Document()
+
+    with doc.create(Section('Can Add Row Passing Many Arguments')):
+        with doc.create(Tabular("|c|c|", booktabs=True)) as table:                
+            
+            mc1 = MultiColumn(1, align='l', data=StandAloneGraphic(
+                          filename=sample_logo_path))
+            mc2 = MultiColumn(1, align='l', data=StandAloneGraphic(
+                          filename=sample_logo_path))
+
+                      
+            table.add_row(mc1, mc2)
+    doc.generate_pdf(clean_tex=False)
+        
+
+def test_tabular_can_add_row_passing_iterable(sample_logo_path):
+    """
+    Test that Tabular can add a row as described in the function body:
+    The second method
+    is to pass a single argument that is an iterable that contains each
+    contents. 
+
+    Returns
+    -------
+    None.
+
+    """
+    doc = Document()
+
+    with doc.create(Section('Can Add Row Passing Iterable')):
+        with doc.create(Tabular("|c|c|", booktabs=True)) as table:                
+                multi_columns_array =  [
+                      MultiColumn(1, align='l', data=StandAloneGraphic(
+                          filename=sample_logo_path)),
+                      MultiColumn(1, align='l', data=StandAloneGraphic(
+                          filename=sample_logo_path))
+                 ]
+                      
+                table.add_row(multi_columns_array)
+    doc.generate_pdf()
+
+if __name__ == '__main__':
+    
+    import os.path as osp    
+    
+    sample_logo_path = osp.abspath(osp.join(
+        __file__[0:-15], "..", "examples", "sample-logo.png"))
+    
+    test_tabular_can_add_row_passing_many_arguments(
+        sample_logo_path=sample_logo_path)
+    test_tabular_can_add_row_passing_iterable(
+        sample_logo_path=sample_logo_path)
+