test(e2e): add ExTester end-to-end test for the Deepnote notebook flow

.gitignore

@@ -74,3 +74,7 @@ vscode.d.ts
 vscode.proposed.*.d.ts
 xunit-test-results.xml
 tsconfig.tsbuildinfo
+
+# ExTester (vscode-extension-tester) E2E artifacts
+test-resources
+.test-extensions

.vscodeignore

@@ -84,6 +84,8 @@ node_modules/**
 obj/**
 logs/**
 out/**
+.test-extensions/**
+test-resources/**
 precommit.hook
 pythonFiles/.env
 pythonFiles/**/*.pyc

package.json

@@ -2672,6 +2672,12 @@
         "test:performance:execution": "cross-env VSC_JUPYTER_CI_TEST_GREP=@executionPerformance CODE_TESTS_WORKSPACE=src/test/datascience TEST_FILES_SUFFIX=*.vscode.test,*.vscode.common.test VSC_JUPYTER_FORCE_LOGGING= node ./out/test/standardTest.node.js",
         "test:performance:notebook": "cross-env VSC_JUPYTER_CI_TEST_GREP=@notebookPerformance VSC_JUPYTER_CI_TEST_DO_NOT_INSTALL_PYTHON_EXT=true CODE_TESTS_WORKSPACE=src/test/datascience TEST_FILES_SUFFIX=*.vscode.test,*.vscode.common.test node ./out/test/standardTest.node.js",
         "test:smoke": "cross-env VSC_JUPYTER_FORCE_LOGGING=true node --no-force-async-hooks-checks ./out/test/smokeTest.node.js",
+        "compile-e2e": "tsc -p ./test/e2e/tsconfig.json",
+        "pretest:e2e": "npm run compile-e2e",
+        "setup:e2e:vscode": "extest get-vscode -c max && extest get-chromedriver -c max",
+        "setup:e2e:deps": "extest install-from-marketplace ms-python.python -e .test-extensions",
+        "setup:e2e": "npm run setup:e2e:vscode && npm run setup:e2e:deps",
+        "test:e2e": "extest setup-and-run \"./out/e2e/suite/*.e2e.test.js\" -c max -o ./test/e2e/settings.json -e .test-extensions -m ./test/e2e/.mocharc.js -i",
         "test:unittests": "mocha --config ./build/.mocha.unittests.js.json ./out/**/*.unit.test.js",
         "test": "npm run test:unittests",
         "typecheck": "tsc -p ./ --noEmit",
@@ -2910,7 +2916,8 @@
         "typescript": "^5.8.3",
         "unicode-properties": "^1.3.1",
         "utf-8-validate": "^5.0.8",
-        "util": "^0.12.4"
+        "util": "^0.12.4",
+        "vscode-extension-tester": "^8.23.0"
     },
     "lint-staged": {
         "src/**/*.{ts,tsx}": [

test/e2e/.mocharc.js

@@ -0,0 +1,9 @@
+// Mocha configuration for the ExTester (vscode-extension-tester) E2E suite.
+// UI tests are slow: the 2s Mocha default is unusable. Individual waits inside the
+// tests are the real guard rails; this is a generous suite-level safety net.
+module.exports = {
+    timeout: 1500000, // 25 min — env creation + first kernel start (venv + toolkit) can be slow
+    retries: 1, // absorb transient UI flakiness with a single retry
+    reporter: 'spec',
+    color: true
+};

test/e2e/fixtures/hello-world.deepnote

@@ -0,0 +1,21 @@
+version: '1.0.0'
+metadata:
+  createdAt: '2025-01-01T00:00:00.000Z'
+  modifiedAt: '2025-01-01T00:00:00.000Z'
+project:
+  id: e2e-hello-world-project
+  name: E2E Hello World
+  notebooks:
+    - id: e2e-hello-world-notebook
+      name: Hello World
+      blocks:
+        - id: e2e-hello-block
+          blockGroup: e2e-group
+          type: code
+          content: |-
+            print("hello world")
+          sortingKey: a0
+          metadata: {}
+      executionMode: block
+      isModule: false
+  settings: {}

test/e2e/settings.json

@@ -0,0 +1,13 @@
+{
+    "files.simpleDialog.enable": true,
+    "window.dialogStyle": "custom",
+    "workbench.editor.enablePreview": false,
+    "workbench.startupEditor": "none",
+    "extensions.ignoreRecommendations": true,
+    "workbench.remoteIndicator.showExtensionRecommendations": false,
+    "git.autoRepositoryDetection": false,
+    "telemetry.telemetryLevel": "off",
+    "update.mode": "none",
+    "jupyter.kernels.trusted": true,
+    "security.workspace.trust.enabled": false
+}