feat(Session.new_window): set up environment

This allows to set up a custom environment when creating a new window.

Author: zappolowski

src/libtmux/session.py

@@ -202,6 +202,7 @@ def new_window(
         attach: bool = True,
         window_index: str = "",
         window_shell: t.Optional[str] = None,
+        environment: t.Optional[t.Dict[str, str]] = None,
     ) -> Window:
         """
         Return :class:`Window` from ``$ tmux new-window``.
@@ -259,6 +260,10 @@ def new_window(
             % (self.id, window_index),
         )
 
+        if environment:
+            for k, v in environment.items():
+                window_args += ("-e%s=%s" % (k, v),)
+
         if window_shell:
             window_args += (window_shell,)
 

tests/test_session.py

@@ -257,3 +257,16 @@ def test_cmd_inserts_sesion_id(session: Session) -> None:
     assert "-t" in cmd.cmd
     assert current_session_id in cmd.cmd
     assert cmd.cmd[-1] == last_arg
+
+
+def test_new_window_with_environment(session: Session) -> None:
+    window = session.new_window(
+        attach=True,
+        window_name="window_with_environment",
+        window_shell="/usr/bin/env PS1='$ ' bash --norc --noprofile",
+        environment={"ENV_VAR": "window"},
+    )
+    pane = window.attached_pane
+    assert pane is not None
+    pane.send_keys("echo $ENV_VAR")
+    assert pane.capture_pane() == ["$ echo $ENV_VAR", "window", "$"]