From 4dc45cd467e821a93af462c3ab4a6295b69c8c87 Mon Sep 17 00:00:00 2001
From: Ronak Bhalgami <ronak@192.168.1.12>
Date: Tue, 7 Oct 2025 12:58:23 +0530
Subject: [PATCH 1/2] tests: add regression test for capteesys with -s; fix
 tee-only behavior

---
 src/_pytest/capture.py          | 22 ++++++++++++++--------
 testing/test_capteesys_issue.py | 16 ++++++++++++++++
 2 files changed, 30 insertions(+), 8 deletions(-)
 create mode 100644 testing/test_capteesys_issue.py

diff --git a/src/_pytest/capture.py b/src/_pytest/capture.py
index 6d98676be5f..33659fac952 100644
--- a/src/_pytest/capture.py
+++ b/src/_pytest/capture.py
@@ -1049,14 +1049,20 @@ def test_output(capteesys):
             assert captured.out == "hello\n"
     """
     capman: CaptureManager = request.config.pluginmanager.getplugin("capturemanager")
-    capture_fixture = CaptureFixture(
-        SysCapture, request, config=dict(tee=True), _ispytest=True
-    )
-    capman.set_fixture(capture_fixture)
-    capture_fixture._start()
-    yield capture_fixture
-    capture_fixture.close()
-    capman.unset_fixture()
+    if capman.is_globally_capturing():
+        capture_fixture = CaptureFixture(
+            SysCapture, request, config=dict(tee=True), _ispytest=True
+        )
+        capman.set_fixture(capture_fixture)
+        capture_fixture._start()
+        yield capture_fixture
+        capture_fixture.close()
+        capman.unset_fixture()
+    else:
+        # capteesys does nothing when global capturing is disabled.
+        # This is so that the "tee" part of cap-tee-sys is not
+        # implemented without the "cap" part.
+        yield CaptureFixture(SysCapture, request, _ispytest=True)
 
 
 @fixture
diff --git a/testing/test_capteesys_issue.py b/testing/test_capteesys_issue.py
new file mode 100644
index 00000000000..b06f217470f
--- /dev/null
+++ b/testing/test_capteesys_issue.py
@@ -0,0 +1,16 @@
+from __future__ import annotations
+
+import sys
+from typing import TYPE_CHECKING
+
+
+if TYPE_CHECKING:
+    from _pytest.capture import CaptureFixture
+    from _pytest.fixtures import SubRequest
+
+
+def test_dummy_test_with_traceback(
+    request: SubRequest, capteesys: CaptureFixture[str]
+) -> None:
+    print("Hello world stdout", flush=True)
+    print("Hello world stderr", file=sys.stderr, flush=True)

From 8985ca201f2c45c0559d11a2a648bea3b862079e Mon Sep 17 00:00:00 2001
From: Ronak Bhalgami <ronak@192.168.1.10>
Date: Fri, 10 Oct 2025 22:27:24 +0530
Subject: [PATCH 2/2] tests(capture): add capteesys regression when -s; remove
 standalone test, integrate into test_capture.py

---
 testing/test_capteesys_issue.py | 16 ----------------
 testing/test_capture.py         | 24 ++++++++++++++++++++++++
 2 files changed, 24 insertions(+), 16 deletions(-)
 delete mode 100644 testing/test_capteesys_issue.py

diff --git a/testing/test_capteesys_issue.py b/testing/test_capteesys_issue.py
deleted file mode 100644
index b06f217470f..00000000000
--- a/testing/test_capteesys_issue.py
+++ /dev/null
@@ -1,16 +0,0 @@
-from __future__ import annotations
-
-import sys
-from typing import TYPE_CHECKING
-
-
-if TYPE_CHECKING:
-    from _pytest.capture import CaptureFixture
-    from _pytest.fixtures import SubRequest
-
-
-def test_dummy_test_with_traceback(
-    request: SubRequest, capteesys: CaptureFixture[str]
-) -> None:
-    print("Hello world stdout", flush=True)
-    print("Hello world stderr", file=sys.stderr, flush=True)
diff --git a/testing/test_capture.py b/testing/test_capture.py
index ffbc440e3bf..2ebd54b11f9 100644
--- a/testing/test_capture.py
+++ b/testing/test_capture.py
@@ -478,6 +478,30 @@ def test_one(capteesys):
         result.stdout.fnmatch_lines(["sTdoUt", "sTdeRr"])  # no tee, just reported
         assert not result.stderr.lines
 
+    def test_capteesys_no_global_capture(self, pytester: Pytester) -> None:
+        """When global capture is disabled (-s), capteesys should not duplicate output.
+
+        It should pass output straight through (printed once) and capteesys.readouterr()
+        should return empty strings since no per-test capture is active.
+        """
+        p = pytester.makepyfile(
+            """\
+            import sys
+
+            def test_one(capteesys):
+                print("sTdoUt")
+                print("sTdeRr", file=sys.stderr)
+                out, err = capteesys.readouterr()
+                assert out == ""
+                assert err == ""
+            """
+        )
+        # Run with -s to disable global capture; ensure each line appears exactly once
+        result = pytester.runpytest_subprocess(p, "-s", "--quiet", "--quiet")
+        assert result.ret == ExitCode.OK
+        assert result.stdout.str().count("sTdoUt") == 1
+        assert result.stderr.str().count("sTdeRr") == 1
+
     def test_capsyscapfd(self, pytester: Pytester) -> None:
         p = pytester.makepyfile(
             """\