Improve tag mapping tests

[cben]

• Add factory :tag_mapping_with_category.
  There are tests in many places approximating this, not all correctly...
• With the factory I was able to add promised test for Do unassign tags when mapped tags list becomes empty #16370
• Going to rely on this in several other tag mapping PRs
  (tag mapping with graph refresh manageiq-providers-kubernetes#126)

https://bugzilla.redhat.com/show_bug.cgi?id=1508437 (master)
https://bugzilla.redhat.com/show_bug.cgi?id=1510095 (gaprindashvili)
https://bugzilla.redhat.com/show_bug.cgi?id=1510096 (fine)

@Ladas @agrare Please review this first, unblocks other PRs to not have circular deps...

[Ladas]

Looks good 👍

[agrare]

❤️ this is awesome @cben

[agrare]

@cben are any of these dependent PRs going to be backported to gaprindashvili?

[cben]

Yes, all of them. I'll check the labels.

[cben]

@miq-bot add-label fine/yes
(this added tests for a fine/backported, gaprindashvili/kackported bugfix. BZ in PR descrpition.
followup PRs about graph refresh will be fine/no of course.)

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit feb7ff3e5c3b043eb22569e3f9157ce65bdca5fd
Author: Adam Grare <[email protected]>
Date:   Mon Nov 13 08:32:08 2017 -0500

    Merge pull request #16453 from cben/mapping_with_category_factory
    
    Improve tag mapping tests
    (cherry picked from commit 66a5465d7360474aaae1315fd9f66e93484b34f4)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1510095

[simaishi]

@cben there is a conflict backporting to Fine branch in spec/models/ems_refresh/save_inventory/save_tags_inventory_spec.rb. Please create a separate PR.

++<<<<<<< HEAD
 +    @tag1 = FactoryGirl.create(:tag, :name => '/managed/amazon:vm:owner')
 +    @tag2 = FactoryGirl.create(:tag, :name => '/managed/kubernetes:container_node:stuff')
 +    @tag3 = FactoryGirl.create(:tag, :name => '/managed/kubernetes:foo') # All
 +
 +    @cat1 = FactoryGirl.create(:category, :description => 'amazon_vm_owner', :tag => @tag1)
 +    @cat2 = FactoryGirl.create(:category, :description => 'department', :tag => @tag2)
 +    @cat3 = FactoryGirl.create(:category, :description => 'location', :tag => @tag3)
++=======
+     @tag1 = mapped_tag('amazon:vm:owner', 'alice')
+     @tag2 = mapped_tag('kubernetes:container_node:stuff', 'jabberwocky')
+     @tag3 = mapped_tag('kubernetes::foo', 'bar') # All entities
++>>>>>>> 66a5465... Merge pull request #16453 from cben/mapping_with_category_factory

[cben]

@simaishi done => #16511

[simaishi]

Backported to Fine via #16511