unit test helper: big revamp (#8894)

* initial commit

* multiple changes:

- TestCaseContext fixture no longer need to autouse=True
- Helper.from_module() allows extra param to specify yaml file
- test_django_check: adjusted .py and .yaml

* set fixtures per testcase

* set fixtures per testcase

* rollback to original state

* patch_ansible_module fixture

- now it works not only in parametrized functions but also directly with args

* tests/unit/plugins/modules/helper.py

- improved encapsulation, class Helper no longer knows details about test cases
- test functions no longer parametrized, that allows using test case fixtures per test function
- renamed 'context' to 'mock'

* enable Helper.from_list(), better param name 'ansible_module'

* adjusted test fiels to new helper

* remove unnecessary .license file

* fix bracket

* fix reference name

* Update tests/unit/plugins/modules/helper.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* revert to parametrized test func instead of multiple funcs

---------

Co-authored-by: Felix Fontein <felix@fontein.de>

tests/unit/plugins/modules/test_facter_facts.yaml

@@ -11,7 +11,8 @@
         a: 1
         b: 2
         c: 3
-  run_command_calls:
+  mocks:
+    run_command:
     - command: [/testbin/facter, --json]
       environ: &env-def {check_rc: true}
       rc: 0
@@ -21,17 +22,18 @@
 - id: with args
   input:
     arguments:
-      - -p
-      - system_uptime
-      - timezone
-      - is_virtual
+    - -p
+    - system_uptime
+    - timezone
+    - is_virtual
   output:
     ansible_facts:
       facter:
         a: 1
         b: 2
         c: 3
-  run_command_calls:
+  mocks:
+    run_command:
     - command: [/testbin/facter, --json, -p, system_uptime, timezone, is_virtual]
       environ: *env-def
       rc: 0