Improve the functional tests

[javiereguiluz]

As pointed by @stof, in this comment at least one of our tests modifies the state of the testing database.

We should improve this by automatically resetting the testing database before each test. In our case this can't be very complex to do because the database is just a file called var/data/blog_test.sqlite

[yceruto]

At now neither test change the DB status, because just we check the response content/status for now, but I'm sure we need that since there is uncovered actions that change the DB status, for example:

• "Create a new post/comment successfully"
• "Edit an existent post successfully"
• "Delete an existent post successfully"

So my vote 👍

[dmaicher]

I propose this PR (#459) that uses my bundle https://github.com/dmaicher/doctrine-test-bundle to have very simple database isolation for all tests 😊 I'm using this bundle in several private and professional projects with mysql, sqlite and postgres - works very nicely.

I changed the tests slightly so first Post 1 is deleted and in the next test its edited. Just to show that all tests are running within database level transactions now that are rolled back at the end of the test.

What do you think?

[stof]

@yceruto deleting an existing post successfully changes the DB (at least I hope it does)

[yceruto]

@stof sure, but before #459 it didn't happen: #444 (comment) so the post was never successfully removed.