diff --git a/depcheck/update-cargo-dependencies.py b/depcheck/update-cargo-dependencies.py
index e69e74d..7b5145f 100755
--- a/depcheck/update-cargo-dependencies.py
+++ b/depcheck/update-cargo-dependencies.py
@@ -1,9 +1,8 @@
 #!/usr/bin/env python3
 
-import subprocess
-import os
 import json
-import sys
+import os
+import subprocess
 
 import semver
 import tomlkit
diff --git a/e2e_tests/conftest.py b/e2e_tests/conftest.py
index 0c23ab6..ef201e1 100644
--- a/e2e_tests/conftest.py
+++ b/e2e_tests/conftest.py
@@ -1,7 +1,5 @@
 import os
 
-from helpers import *
-
 
 def pytest_configure(config):
     os.environ["GIT_AUTHOR_NAME"] = "Example user"
diff --git a/e2e_tests/docker-rest/flask/app.py b/e2e_tests/docker-rest/flask/app.py
index e22c533..3696917 100644
--- a/e2e_tests/docker-rest/flask/app.py
+++ b/e2e_tests/docker-rest/flask/app.py
@@ -2,6 +2,3 @@ from flask import Flask
 
 app = Flask(__name__)
 app.url_map.strict_slashes = False
-
-import github
-import gitlab
diff --git a/e2e_tests/docker-rest/flask/github.py b/e2e_tests/docker-rest/flask/github.py
index e51df42..6d1659d 100644
--- a/e2e_tests/docker-rest/flask/github.py
+++ b/e2e_tests/docker-rest/flask/github.py
@@ -1,10 +1,8 @@
 import os.path
 
-from app import app
-
-from flask import Flask, request, abort, jsonify, make_response
-
 import jinja2
+from app import app
+from flask import abort, jsonify, make_response, request
 
 
 def check_headers():
@@ -48,7 +46,7 @@ def add_pagination(response, page, last_page):
 
 def read_project_files(namespaces=[]):
     last_page = 4
-    page = username = int(request.args.get("page", "1"))
+    page = int(request.args.get("page", "1"))
     response_file = f"./github_api_page_{page}.json.j2"
     if not os.path.exists(response_file):
         return jsonify([])
diff --git a/e2e_tests/docker-rest/flask/gitlab.py b/e2e_tests/docker-rest/flask/gitlab.py
index bbfb26e..605a57d 100644
--- a/e2e_tests/docker-rest/flask/gitlab.py
+++ b/e2e_tests/docker-rest/flask/gitlab.py
@@ -1,10 +1,8 @@
 import os.path
 
-from app import app
-
-from flask import Flask, request, abort, jsonify, make_response
-
 import jinja2
+from app import app
+from flask import abort, jsonify, make_response, request
 
 
 def check_headers():
@@ -48,7 +46,7 @@ def add_pagination(response, page, last_page):
 
 def read_project_files(namespaces=[]):
     last_page = 4
-    page = username = int(request.args.get("page", "1"))
+    page = int(request.args.get("page", "1"))
     response_file = f"./gitlab_api_page_{page}.json"
     if not os.path.exists(response_file):
         return jsonify([])
diff --git a/e2e_tests/helpers.py b/e2e_tests/helpers.py
index b9567e6..e54a15f 100644
--- a/e2e_tests/helpers.py
+++ b/e2e_tests/helpers.py
@@ -1,12 +1,12 @@
 #!/usr/bin/env python3
 
+import hashlib
+import inspect
 import os
 import os.path
+import shutil
 import subprocess
 import tempfile
-import hashlib
-import shutil
-import inspect
 
 import git
 
@@ -176,7 +176,6 @@ class TempGitRemote:
             newobj.remoteid = remoteid
             return newobj, remoteid
         else:
-            refresh = False
             if cachekey not in cls.obj:
                 tmpdir = get_temporary_directory()
                 shell(
diff --git a/e2e_tests/requirements.txt b/e2e_tests/requirements.txt
new file mode 100644
index 0000000..ee93cac
--- /dev/null
+++ b/e2e_tests/requirements.txt
@@ -0,0 +1 @@
+git-python==1.0.3
diff --git a/e2e_tests/test_basic.py b/e2e_tests/test_basic.py
index 6ea5172..dcfd95e 100644
--- a/e2e_tests/test_basic.py
+++ b/e2e_tests/test_basic.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 
-from helpers import *
+from helpers import grm
 
 
 def test_invalid_command():
diff --git a/e2e_tests/test_repos_find.py b/e2e_tests/test_repos_find.py
index 59b0078..2df0bfc 100644
--- a/e2e_tests/test_repos_find.py
+++ b/e2e_tests/test_repos_find.py
@@ -1,12 +1,12 @@
 #!/usr/bin/env python3
 
+import os
 import tempfile
 
-import toml
 import pytest
+import toml
 import yaml
-
-from helpers import *
+from helpers import NonExistentPath, TempGitRepository, grm, shell
 
 
 def test_repos_find_nonexistent():
diff --git a/e2e_tests/test_repos_find_remote.py b/e2e_tests/test_repos_find_remote.py
index df395f8..bc3983e 100644
--- a/e2e_tests/test_repos_find_remote.py
+++ b/e2e_tests/test_repos_find_remote.py
@@ -1,14 +1,13 @@
 #!/usr/bin/env python3
 
-import re
 import os
+import re
+import tempfile
 
-import toml
 import pytest
+import toml
 import yaml
-
-from helpers import *
-
+from helpers import grm
 
 ALTERNATE_DOMAIN = os.environ["ALTERNATE_DOMAIN"]
 PROVIDERS = ["github", "gitlab"]
@@ -275,9 +274,9 @@ def test_repos_find_remote_user(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if override_remote_name:
-                    cfg += f'remote_name = "otherremote"\n'
+                    cfg += 'remote_name = "otherremote"\n'
                 if use_owner:
                     cfg += """
                         [filters]
@@ -475,7 +474,7 @@ def test_repos_find_remote_group(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if use_alternate_endpoint:
                     cfg += f'api_url = "http://{ALTERNATE_DOMAIN}:5000/{provider}"\n'
                 cfg += """
@@ -591,7 +590,7 @@ def test_repos_find_remote_user_and_group(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if use_alternate_endpoint:
                     cfg += f'api_url = "http://{ALTERNATE_DOMAIN}:5000/{provider}"\n'
                 cfg += """
@@ -742,7 +741,7 @@ def test_repos_find_remote_owner(
                 if not worktree_default:
                     cfg += f"worktree = {str(worktree).lower()}\n"
                 if force_ssh:
-                    cfg += f"force_ssh = true\n"
+                    cfg += "force_ssh = true\n"
                 if use_alternate_endpoint:
                     cfg += f'api_url = "http://{ALTERNATE_DOMAIN}:5000/{provider}"\n'
                 cfg += """
@@ -873,13 +872,11 @@ def test_repos_find_remote_owner(
     assert repo["remotes"][0]["name"] == "origin"
     if force_ssh:
         assert (
-            repo["remotes"][0]["url"] == f"ssh://git@example.com/myuser2/myproject3.git"
+            repo["remotes"][0]["url"] == "ssh://git@example.com/myuser2/myproject3.git"
         )
         assert repo["remotes"][0]["type"] == "ssh"
     else:
-        assert (
-            repo["remotes"][0]["url"] == f"https://example.com/myuser2/myproject3.git"
-        )
+        assert repo["remotes"][0]["url"] == "https://example.com/myuser2/myproject3.git"
         assert repo["remotes"][0]["type"] == "https"
 
     group_namespace_1 = [t for t in output["trees"] if t["root"] == "/myroot/mygroup1"][
@@ -923,13 +920,13 @@ def test_repos_find_remote_owner(
         if force_ssh:
             assert (
                 repo["remotes"][0]["url"]
-                == f"ssh://git@example.com/mygroup1/myproject4.git"
+                == "ssh://git@example.com/mygroup1/myproject4.git"
             )
             assert repo["remotes"][0]["type"] == "ssh"
         else:
             assert (
                 repo["remotes"][0]["url"]
-                == f"https://example.com/mygroup1/myproject4.git"
+                == "https://example.com/mygroup1/myproject4.git"
             )
             assert repo["remotes"][0]["type"] == "https"
 
@@ -948,12 +945,11 @@ def test_repos_find_remote_owner(
     assert repo["remotes"][0]["name"] == "origin"
     if force_ssh:
         assert (
-            repo["remotes"][0]["url"]
-            == f"ssh://git@example.com/mygroup2/myproject5.git"
+            repo["remotes"][0]["url"] == "ssh://git@example.com/mygroup2/myproject5.git"
         )
         assert repo["remotes"][0]["type"] == "ssh"
     else:
         assert (
-            repo["remotes"][0]["url"] == f"https://example.com/mygroup2/myproject5.git"
+            repo["remotes"][0]["url"] == "https://example.com/mygroup2/myproject5.git"
         )
         assert repo["remotes"][0]["type"] == "https"
diff --git a/e2e_tests/test_repos_status.py b/e2e_tests/test_repos_status.py
index 8787dea..e9a7511 100644
--- a/e2e_tests/test_repos_status.py
+++ b/e2e_tests/test_repos_status.py
@@ -1,8 +1,6 @@
 #!/usr/bin/env python3
 
-import tempfile
-
-from helpers import *
+from helpers import RepoTree, grm
 
 
 def test_repos_sync_worktree_clone():
diff --git a/e2e_tests/test_repos_sync.py b/e2e_tests/test_repos_sync.py
index bba5b7c..8833aee 100644
--- a/e2e_tests/test_repos_sync.py
+++ b/e2e_tests/test_repos_sync.py
@@ -1,14 +1,21 @@
 #!/usr/bin/env python3
 
-import tempfile
+import os
 import re
+import subprocess
+import tempfile
 import textwrap
 
-import pytest
-import toml
 import git
-
-from helpers import *
+import pytest
+from helpers import (
+    NonExistentPath,
+    TempGitFileRemote,
+    TempGitRepository,
+    checksum_directory,
+    grm,
+    shell,
+)
 
 templates = {
     "repo_simple": {
@@ -291,7 +298,9 @@ def test_repos_sync_unmanaged_repos(configtype):
                 # this removes the prefix (root) from the path (unmanaged_repo)
                 unmanaged_repo_name = os.path.relpath(unmanaged_repo, root)
                 regex = f".*unmanaged.*{unmanaged_repo_name}"
-                assert any([re.match(regex, l) for l in cmd.stderr.lower().split("\n")])
+                assert any(
+                    [re.match(regex, line) for line in cmd.stderr.lower().split("\n")]
+                )
 
 
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
@@ -374,7 +383,7 @@ def test_repos_sync_repo_in_subdirectory(configtype):
                     assert urls[0] == f"file://{remote}"
 
                 cmd = grm(["repos", "sync", "config", "--config", config.name])
-                assert not "found unmanaged repository" in cmd.stderr.lower()
+                assert "found unmanaged repository" not in cmd.stderr.lower()
 
 
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
@@ -419,7 +428,7 @@ def test_repos_sync_nested_clone(configtype):
                     cmd = grm(["repos", "sync", "config", "--config", config.name])
                     print(cmd.stdout)
                     print(cmd.stderr)
-                    assert not "found unmanaged repository" in cmd.stderr.lower()
+                    assert "found unmanaged repository" not in cmd.stderr.lower()
 
 
 @pytest.mark.parametrize("configtype", ["toml", "yaml"])
@@ -720,14 +729,14 @@ def test_repos_sync_invalid_syntax(configtype):
         with open(config.name, "w") as f:
             if configtype == "toml":
                 f.write(
-                    f"""
+                    """
                     [[trees]]
                     root = invalid as there are no quotes ;)
                 """
                 )
             elif configtype == "yaml":
                 f.write(
-                    f"""
+                    """
                     trees:
                     wrong:
                     indentation:
@@ -779,8 +788,6 @@ def test_repos_sync_normal_change_to_worktree(configtype):
                     cmd = grm(["repos", "sync", "config", "--config", config.name])
                     assert cmd.returncode == 0
 
-                    git_dir = os.path.join(target, "test")
-
                     with open(config.name, "w") as f:
                         f.write(
                             templates["worktree_repo_with_remote"][configtype].format(
@@ -810,8 +817,6 @@ def test_repos_sync_worktree_change_to_normal(configtype):
                     cmd = grm(["repos", "sync", "config", "--config", config.name])
                     assert cmd.returncode == 0
 
-                    git_dir = os.path.join(target, "test")
-
                     with open(config.name, "w") as f:
                         f.write(
                             templates["repo_with_remote"][configtype].format(
diff --git a/e2e_tests/test_worktree_clean.py b/e2e_tests/test_worktree_clean.py
index b64172a..cc1958a 100644
--- a/e2e_tests/test_worktree_clean.py
+++ b/e2e_tests/test_worktree_clean.py
@@ -1,8 +1,17 @@
 #!/usr/bin/env python3
 
-import pytest
+import os
 
-from helpers import *
+import pytest
+from helpers import (
+    NonGitDir,
+    TempGitRepository,
+    TempGitRepositoryWorktree,
+    checksum_directory,
+    funcname,
+    grm,
+    shell,
+)
 
 
 def test_worktree_clean():
@@ -153,13 +162,13 @@ def test_worktree_clean_configured_default_branch(
             with open(os.path.join(base_dir, "grm.toml"), "w") as f:
                 if branch_list_empty:
                     f.write(
-                        f"""
+                        """
                         persistent_branches = []
                     """
                     )
                 else:
                     f.write(
-                        f"""
+                        """
                         persistent_branches = [
                             "mybranch"
                         ]
diff --git a/e2e_tests/test_worktree_config_presistent_branch.py b/e2e_tests/test_worktree_config_presistent_branch.py
index e7d2923..cae4c57 100644
--- a/e2e_tests/test_worktree_config_presistent_branch.py
+++ b/e2e_tests/test_worktree_config_presistent_branch.py
@@ -2,7 +2,8 @@
 
 import os.path
 
-from helpers import *
+import git
+from helpers import TempGitRepositoryWorktree, checksum_directory, funcname, grm, shell
 
 
 def test_worktree_never_clean_persistent_branches():
diff --git a/e2e_tests/test_worktree_conversion.py b/e2e_tests/test_worktree_conversion.py
index 7f1448d..b06b32a 100644
--- a/e2e_tests/test_worktree_conversion.py
+++ b/e2e_tests/test_worktree_conversion.py
@@ -1,8 +1,16 @@
 #!/usr/bin/env python3
 
-import tempfile
+import os
 
-from helpers import *
+from helpers import (
+    EmptyDir,
+    NonGitDir,
+    TempGitRepository,
+    TempGitRepositoryWorktree,
+    checksum_directory,
+    funcname,
+    grm,
+)
 
 
 def test_convert():
diff --git a/e2e_tests/test_worktree_fetch.py b/e2e_tests/test_worktree_fetch.py
index a30ef7d..232948b 100644
--- a/e2e_tests/test_worktree_fetch.py
+++ b/e2e_tests/test_worktree_fetch.py
@@ -1,11 +1,17 @@
 #!/usr/bin/env python3
 
-from helpers import *
-
 import re
 
-import pytest
 import git
+import pytest
+from helpers import (
+    EmptyDir,
+    TempGitFileRemote,
+    TempGitRepositoryWorktree,
+    funcname,
+    grm,
+    shell,
+)
 
 
 def test_worktree_fetch():
diff --git a/e2e_tests/test_worktree_rebase.py b/e2e_tests/test_worktree_rebase.py
index 0c73c79..6f18fe3 100644
--- a/e2e_tests/test_worktree_rebase.py
+++ b/e2e_tests/test_worktree_rebase.py
@@ -1,11 +1,11 @@
 #!/usr/bin/env python3
 
-from helpers import *
-
+import os
 import re
 
-import pytest
 import git
+import pytest
+from helpers import TempGitRepositoryWorktree, funcname, grm, shell
 
 
 @pytest.mark.parametrize("pull", [True, False])
diff --git a/e2e_tests/test_worktree_status.py b/e2e_tests/test_worktree_status.py
index d54788f..39eccc6 100644
--- a/e2e_tests/test_worktree_status.py
+++ b/e2e_tests/test_worktree_status.py
@@ -1,10 +1,17 @@
 #!/usr/bin/env python3
 
+import os
 import re
 
-from helpers import *
-
 import pytest
+from helpers import (
+    NonGitDir,
+    TempGitRepository,
+    TempGitRepositoryWorktree,
+    funcname,
+    grm,
+    shell,
+)
 
 
 @pytest.mark.parametrize("has_config", [True, False])
diff --git a/e2e_tests/test_worktrees.py b/e2e_tests/test_worktrees.py
index e5b9b48..8f90580 100644
--- a/e2e_tests/test_worktrees.py
+++ b/e2e_tests/test_worktrees.py
@@ -1,12 +1,18 @@
 #!/usr/bin/env python3
 
-from helpers import *
+import datetime
+import os.path
 
 import git
 import pytest
-import datetime
-
-import os.path
+from helpers import (
+    TempGitRepositoryWorktree,
+    checksum_directory,
+    funcname,
+    grm,
+    shell,
+    tempfile,
+)
 
 
 @pytest.mark.parametrize(
@@ -151,18 +157,20 @@ def test_worktree_add(
             ]
         )
 
-    cachefn = lambda nr: "_".join(
-        [
-            str(nr),
-            str(default_remote),
-            str(local_branch_exists),
-            str(remote_branch_already_exists),
-            str(remote_branch_with_prefix_already_exists),
-            str(remote_count),
-            str(remotes_differ),
-            str(worktree_name),
-        ]
-    )
+    def cachefn(nr):
+        return "_".join(
+            [
+                str(nr),
+                str(default_remote),
+                str(local_branch_exists),
+                str(remote_branch_already_exists),
+                str(remote_branch_with_prefix_already_exists),
+                str(remote_count),
+                str(remotes_differ),
+                str(worktree_name),
+            ]
+        )
+
     remote1_cache_key = cachefn(1)
     remote2_cache_key = cachefn(2)
 
@@ -281,7 +289,7 @@ def test_worktree_add(
                 and remotes_differ
             ):
                 assert (
-                    f"branch exists on multiple remotes, but they deviate"
+                    "branch exists on multiple remotes, but they deviate"
                     in cmd.stderr.lower()
                 )
                 assert len(cmd.stderr.strip().split("\n")) == base + 1