fixed initialisation of environment in Submitter

Author: tclose

pydra/engine/submitter.py

@@ -99,6 +99,8 @@ def __init__(
         **kwargs,
     ):
 
+        from pydra.engine.environments import Native
+
         if worker is None:
             worker = "debug"
 
@@ -120,7 +122,7 @@ def __init__(
 
         self.cache_dir = cache_dir
         self.cache_locations = cache_locations
-        self.environment = environment
+        self.environment = environment if environment is not None else Native()
         self.rerun = rerun
         self.loop = get_open_loop()
         self._own_loop = not self.loop.is_running()

pydra/engine/tests/test_singularity.py

@@ -375,7 +375,7 @@ def test_singularity_cmd_inputspec_copyfile_1(plugin, tmp_path):
     @shell.define
     class Singu(ShellDef["Singu.Outputs"]):
 
-        executable = ["sed", "-is", "'s/hello/hi/'"]
+        executable = ["sed", "-is", "s/hello/hi/"]
 
         orig_file: File = shell.arg(
             position=1,