Add basic testing automation against all version of Python using nox (#…

…2536)

### What

This PR introduces basic support to run tests and examples against all
supported version of Python (currently 3.8 to 3.11). Currently, running
tests and `run_all.py` is supported.

Usage:
```
nox --help
nox -s tests
nox -s run_all -- --save
```

For discoverability and convenience, I added a couple of `just`
commands:

```
just py-tests-allpy
just py-run-all-allpy --save
```

On the way, I added the capability to install example requirements to
`run_all.py`:

```
python scripts/run_all.py --install-requirements
```

Decisions:
- I used [nox](https://nox.thea.codes/en/stable/). The alternative is
the older, more widespread [tox](https://tox.wiki/en/latest/). Reasons:
`noxfile.py` is an actual Python script (as are most of our scripts
already) and `nox` is battle-tested enough to be used in some large
projects, including pip itself.
- Nox is best installed globally on the dev machine (as it manages its
own venvs for running stuff). I updated `setup_dev.sh` accordingly, by
installing `pipx` using the OS package manager, and then using pipx to
install nox. (This is The Right Way™️ to globally install Python CLIs.)

Note: this requires all version of python to be installed and available
on the dev machine. Can't recommend MacPorts enough: `sudo port install
python38 python39 python310 python311`.

Relates to:
- #2445

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)

<!-- This line will get updated when the PR build summary job finishes.
-->
PR Build Summary: https://build.rerun.io/pr/2536

<!-- pr-link-docs:start -->
Docs preview: https://rerun.io/preview/2d89edf/docs
Examples preview: https://rerun.io/preview/2d89edf/examples
<!-- pr-link-docs:end -->

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

.gitignore

@@ -23,3 +23,5 @@ screenshot*.png
 
 # Web demo app build
 web_demo
+
+.nox/

justfile

@@ -45,6 +45,10 @@ py-run-all-web:
 py-run-all-rrd *ARGS:
     just py-run-all --save {{ARGS}}
 
+# Run all examples with all supported Python versions (through nox)
+py-run-all-allpy *ARGS:
+    nox -s run_all -- {{ARGS}}
+
 # Build and install the package into the venv
 py-build *ARGS:
     #!/usr/bin/env bash
@@ -86,6 +90,10 @@ py-lint:
 py-test:
     python -m pytest -vv rerun_py/tests/unit/
 
+# Run tests on all supported Python versions (through nox)
+py-test-allpy:
+    nox -s tests
+
 # Serve the python docs locally
 py-docs-serve:
     mkdocs serve -f rerun_py/mkdocs.yml -w rerun_py

noxfile.py

@@ -0,0 +1,26 @@
+"""Nox sessions.
+
+This file is used by `nox` to run tests and examples against multiple Python versions.
+
+See: http://nox.thea.codes
+"""
+
+from __future__ import annotations
+
+import nox  # type: ignore
+
+
+@nox.session(python=["3.8", "3.9", "3.10", "3.11"])
+def tests(session: nox.Session) -> None:
+    """Run the Python test suite"""
+    session.install("-r", "rerun_py/requirements-build.txt")
+    session.install("./rerun_py")
+    session.run("just", "py-test", external=True)
+
+
+@nox.session(python=["3.8", "3.9", "3.10", "3.11"])
+def run_all(session: nox.Session) -> None:
+    """Run all examples through the run_all.py script (pass args with: "-- <args>")"""
+    # Note: the run_all.py scripts installs all dependencies itself. In particular, we can install from
+    # examples/python/requirements.txt because it includes pyrealsense2, which is not available for mac.
+    session.run("python", "scripts/run_all.py", "--install-requirements", *session.posargs)

scripts/run_all.py

@@ -9,6 +9,7 @@
 import subprocess
 import time
 from glob import glob
+from pathlib import Path
 from types import TracebackType
 from typing import Any
 
@@ -185,6 +186,25 @@ def run_viewer_build(web: bool) -> None:
     assert returncode == 0, f"process exited with error code {returncode}"
 
 
+def run_install_requirements(examples: list[str]) -> None:
+    """Install dependencies for the provided list of examples if they have a requirements.txt file."""
+    args = []
+    for example in examples:
+        req = Path(example) / "requirements.txt"
+        if req.exists():
+            args.extend(["-r", req])
+
+    print("Installing examples requirements…")
+    returncode = subprocess.Popen(
+        [
+            "pip",
+            "install",
+            *args,
+        ]
+    ).wait()
+    assert returncode == 0, f"process exited with error code {returncode}"
+
+
 def run_web(examples: list[str], separate: bool) -> None:
     if separate:
         entries: list[tuple[str, Any, Any]] = []
@@ -283,6 +303,9 @@ def run_native(examples: list[str], separate: bool, close: bool) -> None:
 def main() -> None:
     parser = argparse.ArgumentParser(description="Runs all examples.")
     parser.add_argument("--skip-build", action="store_true", help="Skip building the Python SDK.")
+    parser.add_argument(
+        "--install-requirements", action="store_true", help="Install Python requirements for each example."
+    )
     parser.add_argument("--web", action="store_true", help="Run examples in a web viewer.")
     parser.add_argument(
         "--save",
@@ -306,6 +329,9 @@ def main() -> None:
         if not args.save:
             run_viewer_build(args.web)
 
+    if args.install_requirements:
+        run_install_requirements(examples)
+
     if args.web:
         run_web(examples, separate=args.separate)
         return

scripts/setup_dev.sh

@@ -10,12 +10,12 @@ set -x
 
 cargo install cargo-cranky # Uses lints defined in Cranky.toml. See https://github.com/ericseppanen/cargo-cranky
 cargo install --locked cargo-deny # https://github.com/EmbarkStudios/cargo-deny
-cargo install just # Just a command runner
-cargo install taplo-cli --locked # toml formatter/linter/lsp
-cargo install typos-cli
+cargo install just # https://github.com/casey/just - a command runner
+cargo install taplo-cli --locked # https://github.com/tamasfe/taplo - toml formatter/linter/lsp
+cargo install typos-cli # https://github.com/crate-ci/typos - typo detector
 
 
-packagesNeeded='pngcrush'
+packagesNeeded='pngcrush pipx'
 if [ -x "$(command -v brew)" ];      then brew install $packagesNeeded
 elif [ -x "$(command -v port)" ];    then sudo port install $packagesNeeded
 elif [ -x "$(command -v apt-get)" ]; then sudo apt-get -y install $packagesNeeded
@@ -29,4 +29,11 @@ else
     exit 1
 fi
 
+# ensure pipx is on the path
+pipx ensurepath
+
+# install nox for python testing automation
+# https://nox.thea.codes/en/stable/
+pipx install nox
+
 echo "setup_dev.sh completed!"