Create and activate a Python virtualenv (#7)

Dockerfile

@@ -6,8 +6,9 @@ RUN apt update
 # Rust envvars
 ENV RUSTUP_HOME=/usr/local/rustup \
     CARGO_HOME=/usr/local/cargo \
-    PATH=/usr/local/cargo/bin:$PATH \
-    RUST_VERSION=1.81.0
+    RUST_VERSION=1.81.0 \
+    VIRTUAL_ENV=/var/local/python-venv
+ENV PATH=/usr/local/cargo/bin:$VIRTUAL_ENV/bin:$PATH
 
 # == node ======================
 FROM base AS node
@@ -30,7 +31,8 @@ RUN --mount=type=cache,target=/var/cache/apt,id=framework-runtime-python \
       python3-setuptools \
       python3-wheel \
       python3-dev \
-      python3-venv
+      python3-venv \
+    && python3 -m venv $VIRTUAL_ENV
 
 # == R ===========================
 FROM base AS r

tests/dataloader-languages.test.ts

@@ -1,4 +1,5 @@
-import { binaryVersionTest } from "./index.ts";
+import { test } from "node:test";
+import { binaryVersionTest, runCommandInContainer } from "./index.ts";
 
 const dataLoaderLanguages = [
   { binary: "node", semver: "^20.17" },
@@ -33,3 +34,8 @@ const dataLoaderLanguages = [
 ];
 
 dataLoaderLanguages.forEach(binaryVersionTest);
+
+await test(`A Python virtual environment is activated`, async () => {
+  // should not throw
+  await runCommandInContainer(["pip", "install", "requests"]);
+});

tests/index.ts

@@ -97,8 +97,11 @@ export async function runCommandInContainer(
   docker.modem.demuxStream(attach, stdout, stderr);
   await container.start();
   const wait = (await container.wait()) as { StatusCode: number };
-  if (wait.StatusCode !== 0)
-    throw new Error(`Command failed with status code ${wait.StatusCode}`);
+  if (wait.StatusCode !== 0) {
+    throw new Error(`Command failed with status code ${wait.StatusCode}\n` +
+      `stdout:\n${stdout.string}\n\n` +
+      `stderr:\n${stderr.string}`);
+  }
   return { stdout: stdout.string, stderr: stderr.string };
 }