!squash fix test

Author: tony

src/tmuxp/util.py

@@ -30,14 +30,21 @@ def run_before_script(
 ) -> int:
     """Execute shell script, ``tee``-ing output to both terminal (if TTY) and buffer."""
     script_cmd = shlex.split(str(script_file))
-    proc = subprocess.Popen(
-        script_cmd,
-        cwd=cwd,
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
-        text=True,  # decode to str
-        errors="backslashreplace",
-    )
+
+    try:
+        proc = subprocess.Popen(
+            script_cmd,
+            cwd=cwd,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True,  # decode to str
+            errors="backslashreplace",
+        )
+    except FileNotFoundError as e:
+        raise exc.BeforeLoadScriptNotExists(
+            e,
+            os.path.abspath(script_file),  # NOQA: PTH100
+        ) from e
 
     out_buffer = []
     err_buffer = []