Tests: Add robust tests for silent flag in subshells (#1424)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Ian Thomas <[email protected]>

Author: 3 people

CHANGELOG.md

@@ -53,15 +53,15 @@ Note the changelog here is not correct, presumably due to the recent branch rena
 - Fix expected text depending on IPython version. [#1354](https://github.com/ipython/ipykernel/pull/1354) ([@Carreau](https://github.com/Carreau))
 - Another try at tracking down ResourceWarning with tracemalloc. [#1353](https://github.com/ipython/ipykernel/pull/1353) ([@Carreau](https://github.com/Carreau))
 - Remove deprecated modules since 4.3 (2016). [#1352](https://github.com/ipython/ipykernel/pull/1352) ([@Carreau](https://github.com/Carreau))
-- Try to reenable tests from downstream ipywidgets [#1350](https://github.com/ipython/ipykernel/pull/1350) ([@Carreau](https://github.com/Carreau))
+- Try to re-enable tests from downstream ipywidgets [#1350](https://github.com/ipython/ipykernel/pull/1350) ([@Carreau](https://github.com/Carreau))
 - Disable 3 failing downstream tests, but keep testing the rest. [#1349](https://github.com/ipython/ipykernel/pull/1349) ([@Carreau](https://github.com/Carreau))
-- Licence :: * trove classifers are deprecated [#1348](https://github.com/ipython/ipykernel/pull/1348) ([@Carreau](https://github.com/Carreau))
+- Licence :: * trove classifiers are deprecated [#1348](https://github.com/ipython/ipykernel/pull/1348) ([@Carreau](https://github.com/Carreau))
 - Pin sphinx to resolve docs build failures [#1347](https://github.com/ipython/ipykernel/pull/1347) ([@krassowski](https://github.com/krassowski))
 - Make our own mock kernel methods async [#1346](https://github.com/ipython/ipykernel/pull/1346) ([@Carreau](https://github.com/Carreau))
 - Try to debug non-closed iopub socket [#1345](https://github.com/ipython/ipykernel/pull/1345) ([@Carreau](https://github.com/Carreau))
 - Email is @python.org since 2018 [#1343](https://github.com/ipython/ipykernel/pull/1343) ([@Carreau](https://github.com/Carreau))
 - Remove unused ignores lints. [#1342](https://github.com/ipython/ipykernel/pull/1342) ([@Carreau](https://github.com/Carreau))
-- Enable ruff G002 and fix 6 occurences [#1341](https://github.com/ipython/ipykernel/pull/1341) ([@Carreau](https://github.com/Carreau))
+- Enable ruff G002 and fix 6 occurrences [#1341](https://github.com/ipython/ipykernel/pull/1341) ([@Carreau](https://github.com/Carreau))
 - Check ignores warnings are still relevant. [#1340](https://github.com/ipython/ipykernel/pull/1340) ([@Carreau](https://github.com/Carreau))
 - Move mypy disablinging error codes on a per-file basis [#1338](https://github.com/ipython/ipykernel/pull/1338) ([@Carreau](https://github.com/Carreau))
 - try to fix spyder kernel install [#1337](https://github.com/ipython/ipykernel/pull/1337) ([@Carreau](https://github.com/Carreau))
@@ -70,7 +70,7 @@ Note the changelog here is not correct, presumably due to the recent branch rena
 - Bump mypy [#1333](https://github.com/ipython/ipykernel/pull/1333) ([@Carreau](https://github.com/Carreau))
 - Remove dead code. [#1332](https://github.com/ipython/ipykernel/pull/1332) ([@Carreau](https://github.com/Carreau))
 - Ignore or fix most of the remaining ruff 0.9.6 errors [#1331](https://github.com/ipython/ipykernel/pull/1331) ([@Carreau](https://github.com/Carreau))
-- minor code reformating valid ruff 0.9.6 [#1330](https://github.com/ipython/ipykernel/pull/1330) ([@Carreau](https://github.com/Carreau))
+- minor code reformatting valid ruff 0.9.6 [#1330](https://github.com/ipython/ipykernel/pull/1330) ([@Carreau](https://github.com/Carreau))
 - Some formatting changes to prepare bumping ruff pre-commit. [#1329](https://github.com/ipython/ipykernel/pull/1329) ([@Carreau](https://github.com/Carreau))
 - Manually update Codespell and fix new errors. [#1328](https://github.com/ipython/ipykernel/pull/1328) ([@Carreau](https://github.com/Carreau))
 - Manually update mdformat pre-commit and run it. [#1327](https://github.com/ipython/ipykernel/pull/1327) ([@Carreau](https://github.com/Carreau))

tests/test_subshells.py

@@ -7,11 +7,20 @@
 import platform
 import time
 from collections import Counter
+from queue import Empty
 
 import pytest
 from jupyter_client.blocking.client import BlockingKernelClient
 
-from .utils import TIMEOUT, assemble_output, get_replies, get_reply, new_kernel, wait_for_idle
+from .utils import (
+    TIMEOUT,
+    assemble_output,
+    flush_channels,
+    get_replies,
+    get_reply,
+    new_kernel,
+    wait_for_idle,
+)
 
 # Helpers
 
@@ -40,8 +49,10 @@ def list_subshell_helper(kc: BlockingKernelClient):
     return reply["content"]
 
 
-def execute_request(kc: BlockingKernelClient, code: str, subshell_id: str | None):
-    msg = kc.session.msg("execute_request", {"code": code})
+def execute_request(
+    kc: BlockingKernelClient, code: str, subshell_id: str | None, silent: bool = False
+):
+    msg = kc.session.msg("execute_request", {"code": code, "silent": silent})
     msg["header"]["subshell_id"] = subshell_id
     kc.shell_channel.send(msg)
     return msg
@@ -224,16 +235,16 @@ def test_execute_stop_on_error(are_subshells):
         msg = execute_request(
             kc, "import asyncio; await asyncio.sleep(1); raise ValueError()", subshell_ids[0]
         )
-        msg_ids.append(msg["msg_id"])
+        msg_ids.append(msg["header"]["msg_id"])
         msg = execute_request(kc, "print('hello')", subshell_ids[0])
-        msg_ids.append(msg["msg_id"])
+        msg_ids.append(msg["header"]["msg_id"])
         msg = execute_request(kc, "print('goodbye')", subshell_ids[0])
-        msg_ids.append(msg["msg_id"])
+        msg_ids.append(msg["header"]["msg_id"])
 
         msg = execute_request(kc, "import time; time.sleep(1.5)", subshell_ids[1])
-        msg_ids.append(msg["msg_id"])
+        msg_ids.append(msg["header"]["msg_id"])
         msg = execute_request(kc, "print('other')", subshell_ids[1])
-        msg_ids.append(msg["msg_id"])
+        msg_ids.append(msg["header"]["msg_id"])
 
         replies = get_replies(kc, msg_ids)
 
@@ -313,3 +324,70 @@ def test_idle_message_parent_headers(are_subshells):
         for subshell_id in subshell_ids:
             if subshell_id:
                 delete_subshell_helper(kc, subshell_id)
+
+
+def test_silent_flag_in_subshells():
+    """Verifies that the 'silent' flag suppresses output in main and subshell contexts."""
+    with new_kernel() as kc:
+        subshell_id = None
+        try:
+            flush_channels(kc)
+            # Test silent execution in main shell
+            msg_main_silent = execute_request(kc, "a=1", None, silent=True)
+            reply_main_silent = get_reply(kc, msg_main_silent["header"]["msg_id"])
+            assert reply_main_silent["content"]["status"] == "ok"
+
+            # Test silent execution in subshell
+            subshell_id = create_subshell_helper(kc)["subshell_id"]
+            msg_sub_silent = execute_request(kc, "b=2", subshell_id, silent=True)
+            reply_sub_silent = get_reply(kc, msg_sub_silent["header"]["msg_id"])
+            assert reply_sub_silent["content"]["status"] == "ok"
+
+            # Check for no iopub messages (other than status) from the silent requests
+            for msg_id in [msg_main_silent["header"]["msg_id"], msg_sub_silent["header"]["msg_id"]]:
+                while True:
+                    try:
+                        msg = kc.get_iopub_msg(timeout=0.2)
+                        if msg["header"]["msg_type"] == "status":
+                            continue
+                        pytest.fail(
+                            f"Silent execution produced unexpected IOPub message: {msg['header']['msg_type']}"
+                        )
+                    except Empty:
+                        break
+
+            # Test concurrent silent and non-silent execution
+            msg_silent = execute_request(
+                kc, "import time; time.sleep(0.5); c=3", subshell_id, silent=True
+            )
+            msg_noisy = execute_request(kc, "print('noisy')", None, silent=False)
+
+            # Wait for both replies
+            get_replies(kc, [msg_silent["header"]["msg_id"], msg_noisy["header"]["msg_id"]])
+
+            # Verify that we only receive stream output from the noisy message
+            stdout, stderr = assemble_output(
+                kc.get_iopub_msg, parent_msg_id=msg_noisy["header"]["msg_id"]
+            )
+            assert "noisy" in stdout
+            assert not stderr
+
+            # Verify there is no output from the concurrent silent message
+            while True:
+                try:
+                    msg = kc.get_iopub_msg(timeout=0.2)
+                    if (
+                        msg["header"]["msg_type"] == "status"
+                        and msg["parent_header"].get("msg_id") == msg_silent["header"]["msg_id"]
+                    ):
+                        continue
+                    if msg["parent_header"].get("msg_id") == msg_silent["header"]["msg_id"]:
+                        pytest.fail(
+                            "Silent execution in concurrent setting produced unexpected IOPub message"
+                        )
+                except Empty:
+                    break
+        finally:
+            # Ensure subshell is always deleted
+            if subshell_id:
+                delete_subshell_helper(kc, subshell_id)