Adding failing test.

Author: isoos

test/fixme/v3_close_test.dart

@@ -0,0 +1,69 @@
+import 'package:postgres/postgres_v3_experimental.dart';
+import 'package:test/test.dart';
+
+import '../docker.dart';
+
+void main() {
+  // NOTE: The Docker Container will not close after stopping this test so that needs to be done manually.
+  usePostgresDocker();
+
+  group('service-side connection close',
+      skip: 'the error is not caught or handled properly', () {
+    // ignore: unused_local_variable
+    late final PgConnection conn1;
+    late final PgConnection conn2;
+
+    setUpAll(() async {
+      conn1 = await PgConnection.open(
+        PgEndpoint(
+          host: 'localhost',
+          database: 'dart_test',
+          username: 'dart',
+          password: 'dart',
+        ),
+        sessionSettings: PgSessionSettings(
+          onBadSslCertificate: (cert) => true,
+        ),
+      );
+
+      conn2 = await PgConnection.open(
+        PgEndpoint(
+          host: 'localhost',
+          database: 'dart_test',
+          username: 'postgres',
+          password: 'postgres',
+        ),
+        sessionSettings: PgSessionSettings(
+          onBadSslCertificate: (cert) => true,
+        ),
+      );
+    });
+
+    test('produce error', () async {
+      // get conn1 PID
+      final res = await conn2
+          .execute("SELECT pid FROM pg_stat_activity where usename = 'dart';");
+      final conn1PID = res.first.first as int;
+
+      // Simulate issue by terminating a connection during a query
+      // ignore: unawaited_futures
+      conn1.execute(
+          'select * from pg_stat_activity;'); // comment this out and a different error will appear
+
+      // Terminate the conn1 while the query is running
+      await conn2.execute(
+          'select pg_terminate_backend($conn1PID) from pg_stat_activity;');
+      // this will cause the following exception:
+      // PostgreSQLException (PostgreSQLSeverity.fatal 57P01: terminating connection due to administrator command )
+
+      expect(true, true);
+    });
+
+    tearDownAll(() async {
+      print('closing conn1');
+      await conn1.close(); // this will never close & execution will hang here
+      print('closing conn2');
+      await conn2.close();
+    });
+  });
+}