Attr test

[Jeroendevr]

For the dicttoxml module did not have a direct test where attr_type=True it was only indirectly tested using json2xml. So hereby a small increase of tests.

Forgot to branch properly so hereby also my solution to #165 Although I have some Ideas to make the code cleaner and perhaps another test or two I would like your opinon.

[codecov[bot]]

Codecov Report

Base: 94.04% // Head: 94.24% // Increases project coverage by +0.20% :tada:

Coverage data is based on head (dd6c49b) compared to base (2ca3076). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #169 +/- ## ========================================== + Coverage 94.04% 94.24% +0.20% ========================================== Files 6 6 Lines 537 556 +19 ========================================== + Hits 505 524 +19 Misses 32 32 ``` | [Impacted Files](https://codecov.io/gh/vinitkumar/json2xml/pull/169?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Vinit+Kumar) | Coverage Δ | | |---|---|---| | [json2xml/dicttoxml.py](https://codecov.io/gh/vinitkumar/json2xml/pull/169?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Vinit+Kumar#diff-anNvbjJ4bWwvZGljdHRveG1sLnB5) | `89.28% <100.00%> (+0.14%)` | :arrow_up: | | [tests/test\_dict2xml.py](https://codecov.io/gh/vinitkumar/json2xml/pull/169?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Vinit+Kumar#diff-dGVzdHMvdGVzdF9kaWN0MnhtbC5weQ==) | `100.00% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Vinit+Kumar). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Vinit+Kumar)

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[vinitkumar]

This looks good. This fix is in line with the discussion we had in the twitter thread, right?

[Jeroendevr]

I don't have twitter, I think you meant PR #165 or issue #163? That's correct! this is THE FIX 😀

[vinitkumar]

I don't have twitter, I think you meant PR #165 or issue #163? That's correct! this is THE FIX 😀

I am sorry I did a typo. I meant the GitHub issue thread. Furthermore, I will review the code a bit deeply and if all is good, will merge and cut a release.

[Jeroendevr]

Yes that's great. I'll await your feedback and do some refactoring afterwards.