feat: Add BVT Container Tests

[MadhurAggarwal]

This PR adds BVT Container Tests using Pytest Framework (based on PR-17372) for Azl 4.0

Test Structure

• Each test has a Dockerfile that installs Python3 and copies the helper script into the container
• Then, pytest tests are run that invoke the helper script via container_exec_shell

Math Tests

Tests Python runtime sanity and CPU/arithmetic performance using the Spigot Algorithm for π calculation.

1. Pi Calculation
   • Calculates π to 1,000 decimal places.
2. Sustained Performance Test
   • Verifies that calculating π (up to 10,000 decimal places) completes within a specified time limit (20 seconds)

Network Tests

1. HTTPS Fetch / Online Services Test

   • Fetches weather forecasts from either:
     • Mock weather data hosted in Blob Storage, or
     • forecast.weather.gov
   • In strict mode, the response is parsed and validated.
   • By default, strict mode is disabled.

2. Sustained HTTPS Checks (Core Networking Test)

   • Downloads the Azure Linux 2.0/3.0 repo configs in 50 independent iterations.
   • Parses the downloaded content in strict mode which is enabled by default.
   • Notes
     • I haven't yet included the Azure Linux 4.0 repo configs (https://packages.microsoft.com/azurelinux/4.0/beta/base/x86_64/config.repo) because it is a beta path that might change in the future.
     • The Azl 3.0 implementation for this test also includes: HeaderTest, PingTest, and DownloadFileName to log the test details.
       However, these are disabled by default so I didnt include them yet. I would discuss and add these if needed.

Local Testing using azldev tool:

[Copilot]

Pull request overview

This PR adds two new BVT (Build Verification Test) runtime container test suites for Azure Linux 4.0, placed under base/images/tests/cases/runtime/container-base/. Each suite uses the existing @pytest.mark.dockerfile() pattern to build a custom image (installing python3) on top of the image-under-test, then runs helper scripts via container_exec_shell. The math suite validates Python compute correctness/performance via a spigot π algorithm, and the network suite validates outbound HTTPS connectivity and sustained repo-config fetches. The placement auto-marks them as runtime tests restricted to the container-base family, matching that family's runtime-package-management capability.

Changes:

• Add test_math (π to 1000 places + sustained 10×1000-place compute under a 20s/iteration threshold).
• Add test_network (weather HTTPS fetch with optional strict parsing + 50-iteration sustained repo-config fetch in strict mode).
• Add two Dockerfiles installing python3 and copying helper scripts into /opt/azl-tests/.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
test_math/test_math.py	Pytest entrypoints invoking pi.py for π validation
test_math/pi.py	Spigot π helper; missing docstrings and over-length literals flagged
test_math/Dockerfile	Installs python3, copies pi.py — follows required pattern
test_network/test_network.py	Pytest entrypoints invoking netcheck.py for HTTPS checks
test_network/netcheck.py	HTTP fetch/parse helpers; urlopen lacks timeout, one over-length line
test_network/Dockerfile	Installs python3, copies netcheck.py — follows required pattern

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.