@skirpichev, Further I tried with ```./bin/test -E test_simplify``` too after modifying to ```Integral(posify(1/x + y)[0],(y, 1, 3)).expand() == (Integral(1/_x, (y, 1, 3)) + Integral(_y, (y, 1, 3)))```. But got an ```Assertion error``` with,
```Integral(1/_x, (y, 1, 3)) + Integral(_y, (y, 1, 3)) ==```
```Integral(1/_x, (y, 1, 3)) + Integral(_y, (y, 1, 3))``` being the output. Seriously what could I expect than this?
In other hand most of the test cases in ```test_posify``` uses ```str``` and that would be since the results have ```Dummy``` variables. Moreover if we are to use test cases without quotation marks then the ```Dummy```s (```_x, _y```) should be declared. Hence I would conclude to go with the changes what I have made here. Are you reckon this as a compatible change?