fix: correct computation for range end has been added (#975)

fix: correct computation for range end has been added

Depends-On: #977
playbook:
---
- hosts: localhost
  vars:
    ansible_test_split_in: 3
    number_entries: 10
  tasks:
    - set_fact:  
        _iter_by: "{{ (number_entries|int / ansible_test_split_in)|round(0, 'ceil')|int }}"
    - set_fact:
        _start_at: "{{ (_iter_by|int * ansible_test_do_number|int) - _iter_by|int }}"
    - set_fact:
        _end_at: "{{ _start_at|int + _iter_by|int }}"
    - debug:
        msg: "iter: {{ _iter_by }}, start: {{ _start_at }}, end: {{ _end_at }}"

produces:
➭ for i in {1..3}; do ansible-playbook a.yaml -e ansible_test_do_number=$i 2>&1; done | grep iter
iter: 4, start: 0, end: 4
iter: 4, start: 4, end: 8
iter: 4, start: 8, end: 12


and with the fix:
➭ for i in {1..3}; do ansible-playbook a.yaml -e ansible_test_do_number=$i 2>&1; done | grep iter
iter: 4, start: 0, end: 3
iter: 4, start: 4, end: 7
iter: 4, start: 8, end: 9

roles/ansible-test/tasks/split_targets.yaml

@@ -11,20 +11,19 @@
   failed_when: ansible_test_targets.rc not in [0, 1]
 - set_fact:
     number_entries: "{{ ansible_test_targets.stdout_lines|length }}"
-- set_fact:
-    _iter_by: "{{ (number_entries|int / ansible_test_split_in)|round(0, 'ceil')|int }}"
-- set_fact:
-    _start_at: "{{ (_iter_by|int * ansible_test_do_number|int) - _iter_by|int }}"
-- set_fact:
-    _end_at: "{{ _start_at|int + _iter_by|int }}"
 # Slow tests tend to be closely related.  Hash the names to produce a repeatable
 # list that avoids bringing those tests all into one group
 - set_fact:
     _hashed_targets: "{{ _hashed_targets + [ { 'name': item, 'hash': (item | hash('md5')) } ] }}"
   loop: '{{ ansible_test_targets.stdout_lines }}'
 - set_fact:
     sorted_test_targets: "{{ _hashed_targets | sort(attribute='hash') | map(attribute='name') | list }}"
+# Distribute test targets evenly between workers
+- set_fact:
+    targets_to_test: "{{ targets_to_test | default([]) + [ sorted_test_targets[item] ] }}"
+  when: item % ansible_test_split_in == ansible_test_do_number|int - 1
+  loop: "{{ range(0,number_entries|int)|list }}"
 - set_fact:
-    _integration_targets: "{{ sorted_test_targets[_start_at|int:_end_at|int]|sort|join(' ') }}"
+    _integration_targets: "{{ targets_to_test | default([]) | join(' ') }}"
 - debug:
-    msg: "Do roles: {{ _integration_targets }}"
+    msg: "Do roles: '{{ _integration_targets }}'"