fix: stabilize pip package integration tests

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: eb5f0ccb-cc13-4185-af62-e49f660c239a

Author: edvilme

.github/instructions/testing-workflow.instructions.md

@@ -16,6 +16,10 @@ This guide covers the full testing lifecycle:
 4. **🛠️ Fixing Problems** - Resolve compilation and runtime issues
 5. **✅ Validation** - Ensure coverage and resilience
 
+## Learnings
+
+- Pip commands that return JSON must pass `--disable-pip-version-check`; the process helper combines stderr with stdout, so update notices can otherwise make valid JSON unparseable (1).
+
 ### When to Use This Guide
 
 **User Requests Testing:**

src/managers/builtin/utils.ts

@@ -200,7 +200,7 @@ async function execPipList(environment: PythonEnvironment, log?: LogOutputChanne
     try {
         return await runPython(
             environment.execInfo.run.executable,
-            ['-m', 'pip', 'list', '--format=json', ...(args ?? [])],
+            ['-m', 'pip', 'list', '--format=json', '--disable-pip-version-check', ...(args ?? [])],
             undefined,
             log,
             undefined,

src/test/managers/builtin/pipPackageRefresh.unit.test.ts

@@ -50,4 +50,19 @@ suite('Pip package refresh', () => {
         assert.strictEqual(result, undefined);
         assert.ok(showErrorMessageWithLogsStub.notCalled);
     });
+
+    test('disables the pip version check when listing packages', async () => {
+        const runPythonStub = helpers.runPython as sinon.SinonStub;
+        runPythonStub.resolves('[]');
+
+        await refreshPipPackages(environment, log);
+
+        assert.deepStrictEqual(runPythonStub.firstCall.args[1], [
+            '-m',
+            'pip',
+            'list',
+            '--format=json',
+            '--disable-pip-version-check',
+        ]);
+    });
 });