How should I write a `@testset`

to verify that a function modifies its argument?

For example, here is a function that is passed a vector (of Rationals) `v`

and a row index `row`

:

```
function divideBelow!(v, row)
f = v[row]
for i in row:length(v)
v[i]=v[i]//f
end
return v
end
```

Do I just write multiple lines? Like this:

```
@testset "DivideBelow Tests" begin
v = [3//1, 6//5]
divideBelow(v, 2)
@test v == [3//1, 1//1]
end
```