Add source URL comments to testing assets

This will make it easier for the maintainers to sync fixes and improvements in either direction between the upstream
"template" assets and their installation in this repository.

Taskfile.yml

@@ -65,6 +65,7 @@ tasks:
       - go generate ./...
       - task: go:format
 
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/test-go-task/Taskfile.yml
   go:test:
     desc: Run unit tests
     cmds:
@@ -77,6 +78,7 @@ tasks:
           -coverprofile=coverage_unit.txt \
           {{default .DEFAULT_GO_PACKAGES .GO_PACKAGES}}
 
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/test-go-integration-task/Taskfile.yml
   go:test-integration:
     desc: Run integration tests
     deps:

tests/__init__.py

@@ -1,3 +1,5 @@
+# Source:
+# https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/test-python/__init__.py
 # Copyright 2020 ARDUINO SA(http: // www.arduino.cc/)
 #
 # This software is released under the GNU General Public License version 3,

tests/pytest.ini

@@ -1,3 +1,4 @@
+# Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/test-python/pytest.ini
 [pytest]
 filterwarnings =
     error

tests/test_all.py

@@ -1,3 +1,5 @@
+# Source:
+# https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/test-integration/test_all.py
 # Copyright 2020 ARDUINO SA(http: // www.arduino.cc/)
 #
 # This software is released under the GNU General Public License version 3,