Merge pull request #592 from greyltc/fix-empty-solve

fix unconstrained assembly.solve()

Author: jmwright

cadquery/assembly.py

@@ -401,6 +401,10 @@ def solve(self) -> "Assembly":
         for c in self.constraints:
             constraints.append(((ents[c.objects[0]], ents[c.objects[1]]), c.toPOD()))
 
+        # check if any constraints were specified
+        if not constraints:
+            raise ValueError("At least one constraint required")
+
         # instantiate the solver
         solver = ConstraintSolver(locs, constraints, locked=[lock_ix])
 

tests/test_assembly.py

@@ -212,3 +212,9 @@ def test_duplicate_name(nested_assy):
 
     with pytest.raises(ValueError):
         nested_assy.add(None, name="SECOND")
+
+
+def test_empty_solve(nested_assy):
+
+    with pytest.raises(ValueError):
+        nested_assy.solve()