The Compose file './docker/docker-compose-test-net.yaml' is invalid because:

As an AI language model, I don't have access to the content of the file './docker/docker-compose-test-net.yaml'. However, here are some common reasons that a Docker Compose file may be invalid:

1. Syntax errors: The file may contain syntax errors such as missing brackets, commas, or quotation marks.

2. Incorrect indentation: The indentation of the file may be incorrect, causing errors in the parsing of the file.

3. Incorrect version number: The version number of the file may be incorrect, causing the file to be invalid.

4. Invalid or misspelled service names: The names of the services defined in the file may be misspelled or invalid.

5. Invalid or missing network configuration: The network configuration in the file may be invalid or missing, causing errors in the creation of the network.

6. Invalid or missing environment variables: Environment variables defined in the file may be invalid or missing, causing errors in the execution of the services.

7. Invalid volumes or mounts: The volumes or mounts defined in the file may be invalid, causing errors in the mounting of the directories or files.

8. Invalid or missing dependencies: The dependencies defined in the file may be invalid or missing, causing errors in the execution of the services.

9. Incorrect or missing container configurations: The configurations of the containers defined in the file may be incorrect or missing, causing errors in the creation or execution of the containers.

10. Invalid or missing health checks: The health checks defined in the file may be invalid or missing, causing errors in the monitoring of the containers.