Add asserts avoiding open shells

Author: kraenhansen

Diff for: packages/e2e-tests/test/e2e-editor.spec.ts

@@ -45,6 +45,7 @@ describe('external editor e2e', function () {
 
   afterEach(async function () {
     try {
+      TestShell.assertNoOpenShells();
       await fs.rm(homedir, { recursive: true, force: true });
     } catch (err: any) {
       // On Windows in CI, this can fail with EPERM for some reason.

Diff for: packages/e2e-tests/test/e2e-tls.spec.ts

@@ -59,6 +59,7 @@ describe('e2e TLS', function () {
 
   after(async function () {
     try {
+      TestShell.assertNoOpenShells();
       await fs.rm(homedir, { recursive: true, force: true });
     } catch (err: any) {
       // On Windows in CI, this can fail with EPERM for some reason.

Diff for: packages/e2e-tests/test/e2e.spec.ts

@@ -1379,6 +1379,7 @@ describe('e2e', function () {
 
     afterEach(async function () {
       try {
+        TestShell.assertNoOpenShells();
         await fs.rm(homedir, { recursive: true, force: true });
       } catch (err: any) {
         // On Windows in CI, this can fail with EPERM for some reason.

Diff for: packages/e2e-tests/test/test-shell.ts

@@ -166,6 +166,14 @@ export class TestShell {
     );
   }
 
+  static assertNoOpenShells() {
+    assert.strictEqual(
+      TestShell._openShells.length,
+      0,
+      'Expected TestShell to be enabled, did you call cleanTestShellsAfter or cleanTestShellsAfterEach? Or did you call TestShell.start in an after hook?'
+    );
+  }
+
   debugInformation() {
     return {
       pid: this.process.pid,