Testing build matrix

Changes azure-pipelines to have 3 different stages: fedora-latest,
centos-7 and centos-8.

tests/azure/templates/group_tests.yml

@@ -0,0 +1,29 @@
+
+parameters:
+  - name: scenario
+    type: string
+    default: centos-8
+  - name: build_number
+    type: string
+
+jobs:
+- template: playbook_tests.yml
+  parameters:
+    group_number: 1
+    number_of_groups: 3
+    build_number: ${{ parameters.build_number }}
+    scenario: ${{ parameters.scenario }}
+
+- template: playbook_tests.yml
+  parameters:
+    group_number: 2
+    number_of_groups: 3
+    build_number: ${{ parameters.build_number }}
+    scenario: ${{ parameters.scenario }}
+
+- template: playbook_tests.yml
+  parameters:
+    group_number: 3
+    number_of_groups: 3
+    build_number: ${{ parameters.build_number }}
+    scenario: ${{ parameters.scenario }}

tests/azure/templates/playbook_tests.yml

@@ -16,10 +16,12 @@ parameters:
     type: string
     default: 3.6
   - name: build_number
+    type: string
+
 
 jobs:
-- job: RunTests${{ parameters.group_number }}
-  displayName: Run tests ${{ parameters.group_number }}/${{ parameters.number_of_groups }}
+- job: Test_Group${{ parameters.group_number }}
+  displayName: Run tests ${{ parameters.scenario }} (${{ parameters.group_number }}/${{ parameters.number_of_groups }})
   steps:
   - task: UsePythonVersion@0
     inputs: