---
- hosts: all
  name: Coverage change
  pre_tasks:
    - name: Ensure pip is available
      include_role:
        name: ensure-pip
    - name: Ensure virtualenv is available
      include_role:
        name: ensure-virtualenv
    - name: Ensure tox is available
      include_role:
        name: ensure-tox
      vars:
        ensure_global_symlinks: true
  tasks:
    - name: Environment setup
      shell:
        cmd: |
          set -e
          virtualenv --system-site-packages {{ ansible_user_dir }}/.venv
      args:
        chdir: "{{ ansible_user_dir }}/{{ zuul.project.src_dir }}"
    - name: Measure coverage with the submitted change
      # `awk` will work on lines starting with an alphabetic char,
      # followed by an arbitrary number of chars and finally '.py'
      # this should leave us with table of file coverage measurements.
      # The selected lines will only be procesed if the second column value,
      # representing total number of lines in file, is greater than '0'.
      # This prevents zero division erros, and provides important sanity check on type of the value
      # and on the form of the `tox -e cover` output in general.
      shell:
        cmd: |
          set -e
          source {{ ansible_user_dir }}/.venv/bin/activate
          tox -e cover | awk '/^[[:alpha:]].*\.py/{if ($2 > 0){ print $1 ":" 1-$3/$2; }}'
      args:
        chdir: "{{ ansible_user_dir }}/{{ zuul.project.src_dir }}"
      register: coverage_after
    - name: Transform to dict
      set_fact:
        coverage_after_dict: "{{ coverage_after_dict | default({}) | combine({ item.split(':')[0]: item.split(':')[1] }) }}"
      loop: "{{ coverage_after.stdout_lines }}"
    - name: Record total after change
      shell:
        cmd: |
          set -e
          source {{ ansible_user_dir }}/.venv/bin/activate
          tox -e cover | awk '/TOTAL/{ print 1-$3/$2 }'
      args:
        chdir: "{{ ansible_user_dir }}/{{ zuul.project.src_dir }}"
      register: coverage_after_total
    - name: Checkout previous commit
      shell:
        cmd: |
          set -e
          source {{ ansible_user_dir }}/.venv/bin/activate
          git checkout HEAD^
      args:
        chdir: "{{ ansible_user_dir }}/{{ zuul.project.src_dir }}"
    - name: Measure coverage before submitted change
      # `awk` will work on lines starting with an alphabetic char,
      # followed by an arbitrary number of chars and finally '.py'
      # this should leave us with table of file coverage measurements.
      # The selected lines will only be procesed if the second column value,
      # representing total number of lines in file, is greater than '0'.
      # This prevents zero division erros, and provides important sanity check on type of the value
      # and on the form of the `tox -e cover` output in general.
      shell:
        cmd: |
          set -e
          source {{ ansible_user_dir }}/.venv/bin/activate
          tox -e cover | awk '/^[[:alpha:]].*\.py/{if ($2 > 0){ print $1 ":" 1-$3/$2; }}'
      args:
        chdir: "{{ ansible_user_dir }}/{{ zuul.project.src_dir }}"
      register: coverage_before
    - name: Transform to dict
      set_fact:
        coverage_before_dict: "{{ coverage_before_dict | default({}) | combine({ item.split(':')[0]: item.split(':')[1] }) }}"
      loop: "{{ coverage_before.stdout_lines }}"
    - name: Record total before change
      shell:
        cmd: |
          set -e
          source {{ ansible_user_dir }}/.venv/bin/activate
          tox -e cover | awk '/TOTAL/{ print 1-$3/$2 }'
      args:
        chdir: "{{ ansible_user_dir }}/{{ zuul.project.src_dir }}"
      register: coverage_before_total
    - name: Coverage comparison per file - Check
      assert:
        that: "{{coverage_before_dict[item] | float}} <= {{ coverage_after_dict[item] | float}}"
        fail_msg: |
            Before the change {{ (coverage_before_dict[item] | float)*100 }}% of the lines were covered.
            Now it's {{ (coverage_after_dict[item] | float )*100 }}%. Did you write your unit tests?
        success_msg: |
            File by file code coverage check successful.
      loop: "{{ coverage_after_dict.keys() | intersect(coverage_before_dict.keys()) | sort }}"
    - name: Coverage comparison Total - Check
      assert:
        that: "{{ (coverage_after_total.stdout | float) }} >= {{ (coverage_before_total.stdout | float) }}"
        fail_msg: |
          Before the change {{ (coverage_before_total.stdout | float)*100 }}% of the lines were covered.
          Now it's {{ (coverage_after_total.stdout | float )*100 }}%. Did you write your unit tests?
        success_msg: |
          Code coverage check successful, {{ (coverage_before_total.stdout | float) * 100 }}% of code is now covered.