Add test to protect login bug solution

[jywarren]

#5410 was a great solution for the bug identified in #5405, but I'd like to write a test to prevent this from happening again. It could be a system test:

#5316

Or it could be an integration test, something like this:

plots2/test/integration/login_flow_test.rb

Lines 15 to 26 in 3bef69c

	# This test depend on question based search functionality
	test 'search a question and go through post mechanism if question not found when user is not logged in' do
	get '/post', params: { tags: 'question:question', template: 'question', title: 'What', redirect: 'question' }
	follow_redirect!
	assert_equal '/login', path
	post '/user_sessions', params: { user_session: { username: users(:jeff).username, password: 'secretive' } }
	follow_redirect!
	assert_response :redirect
	assert_redirected_to '/questions/new?tags=question%3Aquestion&template=question&title=What&redirect=question'

Basically we want to try logging in, like here:

https://github.com/publiclab/plots2/blob/master/test/integration/login_flow_test.rb#L22

but with the wrong password, then enter the right password, and show that it really redirects to the dashboard as the solution in #5410 changed.

For anyone looking to learn more about testing, this is a good one!!!

[jywarren]

@40404notfound would you be interested in this one at all? We'd love your help! Thanks again!

[VegChick2]

@jywarren Sure! I am very glad to help.

[IshaGupta18]

@40404notfound how's the work going in on this one? Just checking in in case you are stuck!

[VegChick2]

@IshaGupta18 Thanks a lot ! I just had an extremely busy week so I had to postpone my plan in fixing this issue. Don't worry. I am definitely going to fix this in a few days.

[VegChick2]

Hi, @jywarren @IshaGupta18 , I just added a test case in #5579 for exposing the bug in #5410. The new test should be able to distinguish a buggy one from a correct one.