diff --git a/src/python/jw/pkg/cmds/projects/CmdBuild.py b/src/python/jw/pkg/cmds/projects/CmdBuild.py
index ca8c8bf7..3c83ad83 100644
--- a/src/python/jw/pkg/cmds/projects/CmdBuild.py
+++ b/src/python/jw/pkg/cmds/projects/CmdBuild.py
@@ -112,7 +112,7 @@ class CmdBuild(Cmd):  # export
             return ret
 
         def add_dep_tree(cur, prereq_types, tree, all_deps):
-            log(DEBUG, 'Adding deps "{" ".join(prereq_types)}" of module {cur)')
+            log(DEBUG, f'Adding deps "{" ".join(prereq_types)}" of module {cur}')
             if cur in all_deps:
                 log(DEBUG, 'Already handled module "{cur}"')
                 return 0
diff --git a/src/python/jw/pkg/cmds/secrets/lib/DistroContext.py b/src/python/jw/pkg/cmds/secrets/lib/DistroContext.py
index f1958d93..37780baf 100644
--- a/src/python/jw/pkg/cmds/secrets/lib/DistroContext.py
+++ b/src/python/jw/pkg/cmds/secrets/lib/DistroContext.py
@@ -112,18 +112,6 @@ class DistroContext(FilesContext):
                 ec = Local()
             return (await get(src_uri, content_filter = ProcFilterGpg(ec = ec))).stdout
 
-        def _matches_host_prefix(path: str) -> bool:
-            return re.match(r'^' + host_root_in_tar, path) is not None
-
-        def _crop_host_prefix(path: str) -> bool:
-            return re.sub(r'^' + host_root_in_tar, '', path) is not None
-
-        def _crop_default_prefix(path: str) -> bool:
-            return re.sub(default_rx, '', path) is not None
-
-        def _matches_default_prefix(path: str) -> bool:
-            return re.match(r'^default', path) is not None
-
         def _is_needed_secret(path: str) -> bool:
             return path in secret_paths
 
diff --git a/src/python/jw/pkg/lib/CopyContext.py b/src/python/jw/pkg/lib/CopyContext.py
index cae43bac..5e731736 100644
--- a/src/python/jw/pkg/lib/CopyContext.py
+++ b/src/python/jw/pkg/lib/CopyContext.py
@@ -66,7 +66,7 @@ class CopyContext:
         return self.__dst
 
     async def _run(self) -> None:
-        await self._run()
+        raise NotImplementedError('CopyContext._run() must be overridden')
 
     async def run(self) -> None:
         await self._run()
diff --git a/src/python/jw/pkg/lib/Distro.py b/src/python/jw/pkg/lib/Distro.py
index 76a01571..84c9e5bb 100644
--- a/src/python/jw/pkg/lib/Distro.py
+++ b/src/python/jw/pkg/lib/Distro.py
@@ -29,10 +29,10 @@ class Distro(abc.ABC):
         default_pkg_filter: PackageFilter | None = None,
     ) -> None:
         if id is None:
-            raise ValueError('Tried to instaniate Distro without id')
+            raise ValueError('Tried to instantiate Distro without id')
         if ec is None:
             raise ValueError(
-                f'Tried to instaniate Distro "{id}" without execution context'
+                f'Tried to instantiate Distro "{id}" without execution context'
             )
         self.__exec_context = ec
         self.__id: str | None = None
diff --git a/src/python/jw/pkg/lib/Uri.py b/src/python/jw/pkg/lib/Uri.py
index 13e7d1a5..fa48245d 100644
--- a/src/python/jw/pkg/lib/Uri.py
+++ b/src/python/jw/pkg/lib/Uri.py
@@ -63,7 +63,7 @@ class Uri:
     def scheme(self) -> str:
         ret = self.__p.scheme
         if not ret:
-            return 'file://'
+            return 'file'
         return ret
 
     @cached_property
diff --git a/test/__init__.py b/test/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/test/unit/python/jw/pkg/lib/ProjectConf/test.py b/test/unit/python/jw/pkg/lib/ProjectConf/test.py
index 36a3f558..86aeb1be 100644
--- a/test/unit/python/jw/pkg/lib/ProjectConf/test.py
+++ b/test/unit/python/jw/pkg/lib/ProjectConf/test.py
@@ -1,14 +1,25 @@
+import os
 import tempfile
 from jw.pkg.lib.ProjectConf import ProjectConf
 
 # -- Helper: create temp file and read it --
 
+_tmpfiles: list[str] = []
+
 def _load(text: str) -> ProjectConf:
-    with tempfile.NamedTemporaryFile(mode='w', suffix='.conf', delete=False) as f:
+    with tempfile.NamedTemporaryFile(mode = 'w', suffix = '.conf', delete = False) as f:
         f.write(text)
         f.flush()
+        _tmpfiles.append(f.name)
         return ProjectConf.read(f.name)
 
+
+def _cleanup():
+    for _p in _tmpfiles:
+        os.unlink(_p)
+        del _p
+    _tmpfiles.clear()
+
 # -- Basic construction --
 
 pc = _load('[section]\nkey = value\n')
@@ -250,4 +261,5 @@ assert pc.get_str('section', 'not_a_key') == '[bracket]'
 pc = _load('[section]\nlist = "a", "b", "c"\n')
 assert pc.get_list('section', 'list') == ['a', 'b', 'c']
 
+_cleanup()
 print('All ProjectConf tests passed')
diff --git a/test/unit/python/jw/pkg/lib/Result/test.py b/test/unit/python/jw/pkg/lib/Result/test.py
index b8f25aa9..bee09116 100644
--- a/test/unit/python/jw/pkg/lib/Result/test.py
+++ b/test/unit/python/jw/pkg/lib/Result/test.py
@@ -2,34 +2,34 @@ from jw.pkg.lib.Result import Result
 
 # -- Basic construction --
 
-r = Result(stdout=b'hello', stderr=b'world', status=0)
+r = Result(stdout = b'hello', stderr = b'world', status = 0)
 assert r.status == 0
 assert r.stdout == b'hello'
 assert r.stderr == b'world'
 
 # -- stdout property --
 
-r = Result(stdout=b'test', status=0)
+r = Result(stdout = b'test', status = 0)
 assert r.stdout == b'test'
 
 # stdout_or_none returns raw value
-r = Result(stdout=b'test', status=0)
+r = Result(stdout = b'test', status = 0)
 assert r.stdout_or_none == b'test'
 
 # stdout_str_or_none returns decoded string
-r = Result(stdout=b'test', status=0)
+r = Result(stdout = b'test', status = 0)
 assert r.stdout_str_or_none == 'test'
 
 # stdout_str returns decoded string
-r = Result(stdout=b'test', status=0)
+r = Result(stdout = b'test', status = 0)
 assert r.stdout_str == 'test'
 
 # stdout returns b'' when stdout is None and status == 0
-r = Result(stdout=None, status=0)
+r = Result(stdout = None, status = 0)
 assert r.stdout == b''
 
 # stdout raises when stdout is None and status != 0
-r = Result(stdout=None, status=1)
+r = Result(stdout = None, status = 1)
 try:
     _ = r.stdout
     assert False, 'Should have raised'
@@ -38,27 +38,27 @@ except Exception:
 
 # -- stderr property --
 
-r = Result(stderr=b'error', status=1)
+r = Result(stderr = b'error', status = 1)
 assert r.stderr == b'error'
 
 # stderr_or_none returns raw value
-r = Result(stderr=b'err', status=1)
+r = Result(stderr = b'err', status = 1)
 assert r.stderr_or_none == b'err'
 
 # stderr_str_or_none returns decoded string
-r = Result(stderr=b'err', status=1)
+r = Result(stderr = b'err', status = 1)
 assert r.stderr_str_or_none == 'err'
 
 # stderr_str returns decoded string
-r = Result(stderr=b'err', status=1)
+r = Result(stderr = b'err', status = 1)
 assert r.stderr_str == 'err'
 
 # stderr returns b'' when stderr is None and status != 0 (error case)
-r = Result(stderr=None, status=1)
+r = Result(stderr = None, status = 1)
 assert r.stderr == b''
 
 # stderr raises when stderr is None and status == 0 (success case)
-r = Result(stderr=None, status=0)
+r = Result(stderr = None, status = 0)
 try:
     _ = r.stderr
     assert False, 'Should have raised'
@@ -67,7 +67,7 @@ except Exception:
 
 # -- None outputs --
 
-r = Result(stdout=None, stderr=None, status=1)
+r = Result(stdout = None, stderr = None, status = 1)
 assert r.stdout_or_none is None
 assert r.stderr_or_none is None
 assert r.stdout_str_or_none is None
@@ -75,28 +75,28 @@ assert r.stderr_str_or_none is None
 
 # -- encoding --
 
-r = Result(stdout=b'caf\xc3\xa9', encoding='UTF-8')
+r = Result(stdout = b'caf\xc3\xa9', encoding = 'UTF-8')
 assert r.encoding == 'UTF-8'
 assert r.stdout_str == 'café'
 
-r = Result(stdout=b'test', encoding='UTF-8')
+r = Result(stdout = b'test', encoding = 'UTF-8')
 r.encoding = 'ASCII'
 assert r.encoding == 'ASCII'
 
 # -- strip_output --
 
-r = Result(stdout=b'  spaces  ', status=0)
+r = Result(stdout = b'  spaces  ', status = 0)
 assert r.stdout_str_or_none == '  spaces  '
 
-r = Result(stdout=b'  spaces  ', status=0, strip_output=True)
+r = Result(stdout = b'  spaces  ', status = 0, strip_output = True)
 assert r.stdout_str_or_none == 'spaces'
 
-r = Result(stdout=b'  lines  \n', status=0, strip_output=True)
+r = Result(stdout = b'  lines  \n', status = 0, strip_output = True)
 assert r.stdout_str_or_none == 'lines'
 
 # -- cmd and wd setters --
 
-r = Result(cmd=['echo', 'hello'], wd='/tmp')
+r = Result(cmd = ['echo', 'hello'], wd = '/tmp')
 assert r.cmd == ['echo', 'hello']
 assert r.wd == '/tmp'
 
@@ -107,49 +107,49 @@ assert r.wd == '/home'
 
 # -- summary --
 
-r = Result(stdout=b'output', status=0)
+r = Result(stdout = b'output', status = 0)
 assert 'status 0' in r.summary
 
-r = Result(stderr=b'error', status=1)
+r = Result(stderr = b'error', status = 1)
 assert 'status 1' in r.summary
 assert 'stderr' in r.summary
 
 # -- matches_error --
 
-r = Result(stderr=b'fatal error: missing file', status=128)
+r = Result(stderr = b'fatal error: missing file', status = 128)
 assert r.matches_error('fatal error')
 
-r = Result(stderr=b'fatal error: missing file', status=128)
+r = Result(stderr = b'fatal error: missing file', status = 128)
 assert not r.matches_error('success')
 
-r = Result(stdout=b'ok', stderr=b'', status=0)
+r = Result(stdout = b'ok', stderr = b'', status = 0)
 assert not r.matches_error('.*')
 
-r = Result(stdout=b'ok', stderr=None, status=0)
+r = Result(stdout = b'ok', stderr = None, status = 0)
 assert not r.matches_error('.*')
 
 # -- summarize with custom cmd/wd --
 
-r = Result(stdout=b'out', status=0, cmd=['echo', 'test'], wd='/tmp')
+r = Result(stdout = b'out', status = 0, cmd = ['echo', 'test'], wd = '/tmp')
 assert 'echo' in r.summary or 'status 0' in r.summary
 
 # -- __repr__ --
 
-r = Result(stdout=b'repr test', status=0)
+r = Result(stdout = b'repr test', status = 0)
 s = repr(r)
 assert '0' in s  # verbose=False uses numeric status
 assert 'repr test' in s
 
 # -- encoding setter --
 
-r = Result(stdout=b'test', status=0, encoding='UTF-8')
+r = Result(stdout = b'test', status = 0, encoding = 'UTF-8')
 assert r.encoding == 'UTF-8'
 r.encoding = 'ASCII'
 assert r.encoding == 'ASCII'
 
 # -- strip_output setter --
 
-r = Result(stdout=b'  x  ', status=0, strip_output=False)
+r = Result(stdout = b'  x  ', status = 0, strip_output = False)
 assert r.stdout_str_or_none == '  x  '
 r.strip_output = True
 # strip_output is a property setter, the value is stored
diff --git a/test/unit/python/jw/pkg/lib/Uri/test.py b/test/unit/python/jw/pkg/lib/Uri/test.py
index c88fe364..a435b8b2 100644
--- a/test/unit/python/jw/pkg/lib/Uri/test.py
+++ b/test/unit/python/jw/pkg/lib/Uri/test.py
@@ -19,7 +19,7 @@ assert '<hidden>' in u.safe_full_with_username  # safe version hides password
 
 # Scheme defaults to file
 u = Uri('/local/path')
-assert u.scheme == 'file://'
+assert u.scheme == 'file'
 assert u.protocol == 'file'
 
 # Pimp returns existing Uri unchanged