Reject transformations on SubDataFrame with copycols=false

Author: arkgupta17

test/utils.jl

@@ -186,12 +186,17 @@ end
     df = DataFrame(a = [1, 2, 3], b = [1, 2, 3])
     v = @view df[1:2, :]
 
-    res = select(v, "a", "b", copycols=false)
+    res = select(v, :a, :b, copycols=false)
 
     @test size(res) == (2, 2)
     @test names(res) == ["a", "b"]
-    @test res.a === [1, 2]
-    @test res.b === [1, 2]
+
+    @test res.a == v.a
+    @test res.b == v.b
+
+    @test parent(res.a) === parent(v.a)
+    @test parent(res.b) === parent(v.b)
 end
 
 
+