test: Prevent test suite from renderering Textual UI

Send client stdout and stderr to PIPE so Textual UI will not be shown on
tests output.

Signed-off-by: Vitor Espindola <[email protected]>

tests/integration/test_main.py

@@ -969,6 +969,7 @@ def test_tree_generated(self, tmp_path, simple_test_file):
                 str(results_file),
             ],
             cwd=str(tmp_path),
+            stderr=subprocess.DEVNULL,
             text=True,
             input="q",
         )
@@ -991,6 +992,7 @@ def test_temporary_allocations_tree(self, tmp_path, simple_test_file):
                 str(results_file),
             ],
             cwd=str(tmp_path),
+            stderr=subprocess.DEVNULL,
             text=True,
             input="q",
         )
@@ -1413,6 +1415,7 @@ def test_live_tracking(self, tmp_path, simple_test_file, free_port):
                 str(free_port),
             ],
             stdout=subprocess.PIPE,
+            stderr=subprocess.DEVNULL,
             stdin=subprocess.PIPE,
         )
 
@@ -1536,6 +1539,7 @@ def test_live_tracking_server_when_client_disconnects(self, free_port, tmp_path)
             ],
             stdin=subprocess.PIPE,
             stdout=subprocess.PIPE,
+            stderr=subprocess.DEVNULL,
         )
 
         # WHEN