test(env): Use wait_for_line() for environment propagation tests

why: Control mode is asynchronous; tests assuming immediate output
availability with capture_pane()[-2] fail intermittently.
what:
- Update 6 environment tests to use wait_for_line() polling
- Add shell prompt handling to _match() function
- Import wait_for_line helper in legacy test files

Affected tests:
- test_session.py: test_new_session_with_environment
- test_session.py: test_new_window_with_environment
- test_window.py: test_split_window_with_environment
- legacy_api/test_session.py: test_new_session_with_environment
- legacy_api/test_session.py: test_new_window_with_environment
- legacy_api/test_window.py: test_split_window_with_environment

Author: tony

tests/legacy_api/test_session.py

@@ -14,6 +14,7 @@
 from libtmux.test.constants import TEST_SESSION_PREFIX
 from libtmux.test.random import namer
 from libtmux.window import Window
+from tests.helpers import wait_for_line
 
 if t.TYPE_CHECKING:
     from libtmux.server import Server
@@ -280,4 +281,11 @@ def test_new_window_with_environment(
     assert pane is not None
     for k, v in environment.items():
         pane.send_keys(f"echo ${k}")
-        assert pane.capture_pane()[-2] == v
+
+        def _match(line: str, expected: str = v) -> bool:
+            stripped = line.strip()
+            # Match exact value or value after shell prompt ($ prefix)
+            return stripped == expected or stripped == f"$ {expected}"
+
+        lines = wait_for_line(pane, _match)
+        assert any(_match(line) for line in lines)

tests/legacy_api/test_window.py

@@ -13,6 +13,7 @@
 from libtmux.pane import Pane
 from libtmux.server import Server
 from libtmux.window import Window
+from tests.helpers import wait_for_line
 
 if t.TYPE_CHECKING:
     from libtmux.session import Session
@@ -383,4 +384,11 @@ def test_split_window_with_environment(
     assert pane is not None
     for k, v in environment.items():
         pane.send_keys(f"echo ${k}")
-        assert pane.capture_pane()[-2] == v
+
+        def _match(line: str, expected: str = v) -> bool:
+            stripped = line.strip()
+            # Match exact value or value after shell prompt ($ prefix)
+            return stripped == expected or stripped == f"$ {expected}"
+
+        lines = wait_for_line(pane, _match)
+        assert any(_match(line) for line in lines)

tests/test_session.py

@@ -333,7 +333,9 @@ def test_new_window_with_environment(
         pane.send_keys(f"echo ${k}")
 
         def _match(line: str, expected: str = v) -> bool:
-            return line.strip() == expected
+            stripped = line.strip()
+            # Match exact value or value after shell prompt ($ prefix)
+            return stripped == expected or stripped == f"$ {expected}"
 
         lines = wait_for_line(pane, _match)
         assert any(_match(line) for line in lines)

tests/test_window.py

@@ -462,7 +462,9 @@ def test_split_with_environment(
         pane.send_keys(f"echo ${k}")
 
         def _match(line: str, expected: str = v) -> bool:
-            return line.strip() == expected
+            stripped = line.strip()
+            # Match exact value or value after shell prompt ($ prefix)
+            return stripped == expected or stripped == f"$ {expected}"
 
         lines = wait_for_line(pane, _match)
         assert any(_match(line) for line in lines)