Extrude with both=True fix (#321)

Extrude with both=True will result in a single solid.

* combineWithBase fix
* Allow to self-fuse a compound
* Formatting fix
* Test if extrude with both=True fuses the solids

Author: adam-urbanczyk

cadquery/cq.py

@@ -2675,6 +2675,8 @@ def _combineWithBase(self, obj):
         r = obj
         if baseSolid is not None:
             r = baseSolid.fuse(obj)
+        elif isinstance(obj, Compound):
+            r = obj.fuse()
 
         return self.newObject([r])
 

cadquery/occ_impl/shapes.py

@@ -1997,7 +1997,12 @@ def fuse(self, *toFuse):
         fuse_op = BRepAlgoAPI_Fuse()
         # fuse_op.SetFuzzyValue(TOLERANCE)
 
-        rv = self._bool_op(self, toFuse, fuse_op)
+        args = tuple(self) + toFuse
+
+        if len(args) <= 1:
+            rv = self
+        else:
+            rv = self._bool_op(args[:1], args[1:], fuse_op)
 
         # fuse_op.RefineEdges()
         # fuse_op.FuseEdges()

tests/test_cadquery.py

@@ -2548,6 +2548,8 @@ def testExtrude(self):
         # extrude symmetrically
         s = Workplane("XY").circle(r).extrude(h, both=True)
 
+        self.assertTrue(len(s.val().Solids()) == 1)
+
         top_face = s.faces(">Z")
         bottom_face = s.faces("<Z")