diff --git a/repo2docker/__main__.py b/repo2docker/__main__.py
index 1b52b1ae..c3e7ef7e 100644
--- a/repo2docker/__main__.py
+++ b/repo2docker/__main__.py
@@ -52,7 +52,7 @@ class MimicDockerEnvHandling(argparse.Action):
         #  key          pass using current value, or don't pass
         if "=" not in values:
             try:
-                value_to_append = "{}={}".format(values, os.environ[values])
+                value_to_append = f"{values}={os.environ[values]}"
             except KeyError:
                 # no local def, so don't pass
                 return
diff --git a/repo2docker/_version.py b/repo2docker/_version.py
index 44284036..aca7b127 100644
--- a/repo2docker/_version.py
+++ b/repo2docker/_version.py
@@ -84,7 +84,7 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False, env=
                 stderr=(subprocess.PIPE if hide_stderr else None),
             )
             break
-        except EnvironmentError:
+        except OSError:
             e = sys.exc_info()[1]
             if e.errno == errno.ENOENT:
                 continue
@@ -94,7 +94,7 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False, env=
             return None, None
     else:
         if verbose:
-            print("unable to find command, tried %s" % (commands,))
+            print(f"unable to find command, tried {commands}")
         return None, None
     stdout = p.communicate()[0].strip()
     if sys.version_info[0] >= 3:
@@ -147,7 +147,7 @@ def git_get_keywords(versionfile_abs):
     # _version.py.
     keywords = {}
     try:
-        f = open(versionfile_abs, "r")
+        f = open(versionfile_abs)
         for line in f.readlines():
             if line.strip().startswith("git_refnames ="):
                 mo = re.search(r'=\s*"(.*)"', line)
@@ -162,7 +162,7 @@ def git_get_keywords(versionfile_abs):
                 if mo:
                     keywords["date"] = mo.group(1)
         f.close()
-    except EnvironmentError:
+    except OSError:
         pass
     return keywords
 
@@ -186,11 +186,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         if verbose:
             print("keywords are unexpanded, not using")
         raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
-    refs = set([r.strip() for r in refnames.strip("()").split(",")])
+    refs = {r.strip() for r in refnames.strip("()").split(",")}
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
     TAG = "tag: "
-    tags = set([r[len(TAG) :] for r in refs if r.startswith(TAG)])
+    tags = {r[len(TAG) :] for r in refs if r.startswith(TAG)}
     if not tags:
         # Either we're using git < 1.8.3, or there really are no tags. We use
         # a heuristic: assume all version tags have a digit. The old git %d
@@ -199,7 +199,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # between branches and tags. By ignoring refnames without digits, we
         # filter out many common branch names like "release" and
         # "stabilization", as well as "HEAD" and "master".
-        tags = set([r for r in refs if re.search(r"\d", r)])
+        tags = {r for r in refs if re.search(r"\d", r)}
         if verbose:
             print("discarding '%s', no digits" % ",".join(refs - tags))
     if verbose:
@@ -302,7 +302,7 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
             if verbose:
                 fmt = "tag '%s' doesn't start with prefix '%s'"
                 print(fmt % (full_tag, tag_prefix))
-            pieces["error"] = "tag '%s' doesn't start with prefix '%s'" % (
+            pieces["error"] = "tag '{}' doesn't start with prefix '{}'".format(
                 full_tag,
                 tag_prefix,
             )
diff --git a/repo2docker/app.py b/repo2docker/app.py
index e11f36b6..718b12b2 100755
--- a/repo2docker/app.py
+++ b/repo2docker/app.py
@@ -568,7 +568,7 @@ class Repo2Docker(Application):
                     )
                     last_emit_time = time.time()
         self.log.info(
-            "Successfully pushed {}".format(self.output_image_spec),
+            f"Successfully pushed {self.output_image_spec}",
             extra=dict(phase=R2dState.PUSHING),
         )
 
@@ -767,7 +767,7 @@ class Repo2Docker(Application):
                         self.subdir,
                         extra=dict(phase=R2dState.FAILED),
                     )
-                    raise FileNotFoundError("Could not find {}".format(checkout_path))
+                    raise FileNotFoundError(f"Could not find {checkout_path}")
 
             with chdir(checkout_path):
                 for BP in self.buildpacks:
diff --git a/repo2docker/buildpacks/base.py b/repo2docker/buildpacks/base.py
index 57ed2f35..16476e9d 100644
--- a/repo2docker/buildpacks/base.py
+++ b/repo2docker/buildpacks/base.py
@@ -462,7 +462,7 @@ class BuildPack:
         last_user = "root"
         for user, script in self.get_build_scripts():
             if last_user != user:
-                build_script_directives.append("USER {}".format(user))
+                build_script_directives.append(f"USER {user}")
                 last_user = user
             build_script_directives.append(
                 "RUN {}".format(textwrap.dedent(script.strip("\n")))
@@ -472,7 +472,7 @@ class BuildPack:
         last_user = "root"
         for user, script in self.get_assemble_scripts():
             if last_user != user:
-                assemble_script_directives.append("USER {}".format(user))
+                assemble_script_directives.append(f"USER {user}")
                 last_user = user
             assemble_script_directives.append(
                 "RUN {}".format(textwrap.dedent(script.strip("\n")))
@@ -482,7 +482,7 @@ class BuildPack:
         last_user = "root"
         for user, script in self.get_preassemble_scripts():
             if last_user != user:
-                preassemble_script_directives.append("USER {}".format(user))
+                preassemble_script_directives.append(f"USER {user}")
                 last_user = user
             preassemble_script_directives.append(
                 "RUN {}".format(textwrap.dedent(script.strip("\n")))
@@ -616,8 +616,7 @@ class BuildPack:
 
         build_kwargs.update(extra_build_kwargs)
 
-        for line in client.build(**build_kwargs):
-            yield line
+        yield from client.build(**build_kwargs)
 
 
 class BaseImage(BuildPack):
diff --git a/repo2docker/buildpacks/conda/__init__.py b/repo2docker/buildpacks/conda/__init__.py
index 4408ad8e..662e70bf 100644
--- a/repo2docker/buildpacks/conda/__init__.py
+++ b/repo2docker/buildpacks/conda/__init__.py
@@ -377,7 +377,7 @@ class CondaBuildPack(BaseImage):
                     r"""
                     echo auth-none=1 >> /etc/rstudio/rserver.conf && \
                     echo auth-minimum-user-id=0 >> /etc/rstudio/rserver.conf && \
-                    echo "rsession-which-r={0}/bin/R" >> /etc/rstudio/rserver.conf && \
+                    echo "rsession-which-r={}/bin/R" >> /etc/rstudio/rserver.conf && \
                     echo www-frame-origin=same >> /etc/rstudio/rserver.conf
                     """.format(
                         env_prefix
@@ -387,7 +387,7 @@ class CondaBuildPack(BaseImage):
                     "${NB_USER}",
                     # Register the jupyter kernel
                     r"""
-                 R --quiet -e "IRkernel::installspec(prefix='{0}')"
+                 R --quiet -e "IRkernel::installspec(prefix='{}')"
                  """.format(
                         env_prefix
                     ),
diff --git a/repo2docker/buildpacks/docker.py b/repo2docker/buildpacks/docker.py
index 5f0c2fb3..e0ccfc95 100644
--- a/repo2docker/buildpacks/docker.py
+++ b/repo2docker/buildpacks/docker.py
@@ -57,5 +57,4 @@ class DockerBuildPack(BuildPack):
 
         build_kwargs.update(extra_build_kwargs)
 
-        for line in client.build(**build_kwargs):
-            yield line
+        yield from client.build(**build_kwargs)
diff --git a/repo2docker/buildpacks/legacy/__init__.py b/repo2docker/buildpacks/legacy/__init__.py
index 7f5d004f..a1b91e02 100644
--- a/repo2docker/buildpacks/legacy/__init__.py
+++ b/repo2docker/buildpacks/legacy/__init__.py
@@ -20,7 +20,7 @@ class LegacyBinderDockerBuildPack:
         """Check if current repo should be built with the Legacy BuildPack."""
         log = logging.getLogger("repo2docker")
         try:
-            with open("Dockerfile", "r") as f:
+            with open("Dockerfile") as f:
                 for line in f:
                     if line.startswith("FROM"):
                         if "andrewosh/binder-base" in line.split("#")[0].lower():
diff --git a/repo2docker/buildpacks/python/__init__.py b/repo2docker/buildpacks/python/__init__.py
index 7ea2a826..0c12f91b 100644
--- a/repo2docker/buildpacks/python/__init__.py
+++ b/repo2docker/buildpacks/python/__init__.py
@@ -67,7 +67,7 @@ class PythonBuildPack(CondaBuildPack):
             scripts.append(
                 (
                     "${NB_USER}",
-                    '{} install --no-cache-dir -r "{}"'.format(pip, requirements_file),
+                    f'{pip} install --no-cache-dir -r "{requirements_file}"',
                 )
             )
         return scripts
@@ -126,9 +126,7 @@ class PythonBuildPack(CondaBuildPack):
 
         # setup.py exists *and* binder dir is not used
         if not self.binder_dir and os.path.exists(setup_py):
-            assemble_scripts.append(
-                ("${NB_USER}", "{} install --no-cache-dir .".format(pip))
-            )
+            assemble_scripts.append(("${NB_USER}", f"{pip} install --no-cache-dir ."))
         return assemble_scripts
 
     def detect(self):
diff --git a/repo2docker/buildpacks/r.py b/repo2docker/buildpacks/r.py
index eaf44b2b..9009a4d8 100644
--- a/repo2docker/buildpacks/r.py
+++ b/repo2docker/buildpacks/r.py
@@ -139,7 +139,7 @@ class RBuildPack(PythonBuildPack):
                 self._checkpoint_date = datetime.date.today() - datetime.timedelta(
                     days=2
                 )
-                self._runtime = "r-{}".format(str(self._checkpoint_date))
+                self._runtime = f"r-{str(self._checkpoint_date)}"
             return True
 
     def get_env(self):
@@ -223,7 +223,7 @@ class RBuildPack(PythonBuildPack):
         for i in range(max_days_prior):
             try_date = snapshot_date - datetime.timedelta(days=i)
             # Fall back to MRAN if packagemanager.rstudio.com doesn't have it
-            url = "https://mran.microsoft.com/snapshot/{}".format(try_date.isoformat())
+            url = f"https://mran.microsoft.com/snapshot/{try_date.isoformat()}"
             r = requests.head(url)
             if r.ok:
                 return url
diff --git a/repo2docker/contentproviders/dataverse.py b/repo2docker/contentproviders/dataverse.py
index a1c57caa..c308c2d0 100644
--- a/repo2docker/contentproviders/dataverse.py
+++ b/repo2docker/contentproviders/dataverse.py
@@ -20,7 +20,7 @@ class Dataverse(DoiProvider):
 
     def __init__(self):
         data_file = os.path.join(os.path.dirname(__file__), "dataverse.json")
-        with open(data_file, "r") as fp:
+        with open(data_file) as fp:
             self.hosts = json.load(fp)["installations"]
         super().__init__()
 
@@ -97,7 +97,7 @@ class Dataverse(DoiProvider):
         record_id = spec["record"]
         host = spec["host"]
 
-        yield "Fetching Dataverse record {}.\n".format(record_id)
+        yield f"Fetching Dataverse record {record_id}.\n"
         url = "{}/api/datasets/:persistentId?persistentId={}".format(
             host["url"], record_id
         )
@@ -114,8 +114,7 @@ class Dataverse(DoiProvider):
             file_ref = {"download": file_url, "filename": filename}
             fetch_map = {key: key for key in file_ref.keys()}
 
-            for line in self.fetch_file(file_ref, fetch_map, output_dir):
-                yield line
+            yield from self.fetch_file(file_ref, fetch_map, output_dir)
 
         new_subdirs = os.listdir(output_dir)
         # if there is only one new subdirectory move its contents
diff --git a/repo2docker/contentproviders/doi.py b/repo2docker/contentproviders/doi.py
index c1941ba8..01d048ec 100644
--- a/repo2docker/contentproviders/doi.py
+++ b/repo2docker/contentproviders/doi.py
@@ -23,7 +23,7 @@ class DoiProvider(ContentProvider):
         self.session = Session()
         self.session.headers.update(
             {
-                "user-agent": "repo2docker {}".format(__version__),
+                "user-agent": f"repo2docker {__version__}",
             }
         )
 
@@ -38,7 +38,7 @@ class DoiProvider(ContentProvider):
         if not isinstance(req, request.Request):
             req = request.Request(req)
 
-        req.add_header("User-Agent", "repo2docker {}".format(__version__))
+        req.add_header("User-Agent", f"repo2docker {__version__}")
         if headers is not None:
             for key, value in headers.items():
                 req.add_header(key, value)
@@ -52,7 +52,7 @@ class DoiProvider(ContentProvider):
             doi = normalize_doi(doi)
 
             try:
-                resp = self._request("https://doi.org/{}".format(doi))
+                resp = self._request(f"https://doi.org/{doi}")
                 resp.raise_for_status()
             # If the DOI doesn't resolve, just return URL
             except HTTPError:
@@ -67,26 +67,26 @@ class DoiProvider(ContentProvider):
         # file related to a record
         file_url = deep_get(file_ref, host["download"])
         fname = deep_get(file_ref, host["filename"])
-        logging.debug("Downloading file {} as {}\n".format(file_url, fname))
+        logging.debug(f"Downloading file {file_url} as {fname}\n")
 
-        yield "Requesting {}\n".format(file_url)
+        yield f"Requesting {file_url}\n"
         resp = self._request(file_url, stream=True)
         resp.raise_for_status()
 
         if path.dirname(fname):
             sub_dir = path.join(output_dir, path.dirname(fname))
             if not path.exists(sub_dir):
-                yield "Creating {}\n".format(sub_dir)
+                yield f"Creating {sub_dir}\n"
                 makedirs(sub_dir, exist_ok=True)
 
         dst_fname = path.join(output_dir, fname)
         with open(dst_fname, "wb") as dst:
-            yield "Fetching {}\n".format(fname)
+            yield f"Fetching {fname}\n"
             for chunk in resp.iter_content(chunk_size=None):
                 dst.write(chunk)
 
         if unzip and is_zipfile(dst_fname):
-            yield "Extracting {}\n".format(fname)
+            yield f"Extracting {fname}\n"
             zfile = ZipFile(dst_fname)
             zfile.extractall(path=output_dir)
             zfile.close()
@@ -106,4 +106,4 @@ class DoiProvider(ContentProvider):
                 copytree(path.join(output_dir, d), output_dir)
                 shutil.rmtree(path.join(output_dir, d))
 
-            yield "Fetched files: {}\n".format(os.listdir(output_dir))
+            yield f"Fetched files: {os.listdir(output_dir)}\n"
diff --git a/repo2docker/contentproviders/figshare.py b/repo2docker/contentproviders/figshare.py
index 4b1517fc..5d27684d 100644
--- a/repo2docker/contentproviders/figshare.py
+++ b/repo2docker/contentproviders/figshare.py
@@ -91,10 +91,9 @@ class Figshare(DoiProvider):
         only_one_file = len(files) == 1
         for file_ref in files:
             unzip = file_ref["name"].endswith(".zip") and only_one_file
-            for line in self.fetch_file(file_ref, host, output_dir, unzip):
-                yield line
+            yield from self.fetch_file(file_ref, host, output_dir, unzip)
 
     @property
     def content_id(self):
         """The Figshare article ID"""
-        return "{}.v{}".format(self.article_id, self.article_version)
+        return f"{self.article_id}.v{self.article_version}"
diff --git a/repo2docker/contentproviders/git.py b/repo2docker/contentproviders/git.py
index 345298c7..9e5fb48e 100644
--- a/repo2docker/contentproviders/git.py
+++ b/repo2docker/contentproviders/git.py
@@ -29,13 +29,12 @@ class Git(ContentProvider):
                 # this prevents HEAD's submodules to be cloned if ref doesn't have them
                 cmd.extend(["--no-checkout"])
             cmd.extend([repo, output_dir])
-            for line in execute_cmd(cmd, capture=yield_output):
-                yield line
+            yield from execute_cmd(cmd, capture=yield_output)
 
         except subprocess.CalledProcessError as e:
-            msg = "Failed to clone repository from {repo}".format(repo=repo)
+            msg = f"Failed to clone repository from {repo}"
             if ref != "HEAD":
-                msg += " (ref {ref})".format(ref=ref)
+                msg += f" (ref {ref})"
             msg += "."
             raise ContentProviderException(msg) from e
 
@@ -54,23 +53,21 @@ class Git(ContentProvider):
                         "specifying `--ref`."
                     )
                 else:
-                    msg = "Failed to check out ref {}".format(ref)
+                    msg = f"Failed to check out ref {ref}"
                 raise ValueError(msg)
             # We don't need to explicitly checkout things as the reset will
             # take care of that. If the hash is resolved above, we should be
             # able to reset to it
-            for line in execute_cmd(
+            yield from execute_cmd(
                 ["git", "reset", "--hard", hash], cwd=output_dir, capture=yield_output
-            ):
-                yield line
+            )
 
         # ensure that git submodules are initialised and updated
-        for line in execute_cmd(
+        yield from execute_cmd(
             ["git", "submodule", "update", "--init", "--recursive"],
             cwd=output_dir,
             capture=yield_output,
-        ):
-            yield line
+        )
 
         cmd = ["git", "rev-parse", "HEAD"]
         sha1 = subprocess.Popen(cmd, stdout=subprocess.PIPE, cwd=output_dir)
diff --git a/repo2docker/contentproviders/hydroshare.py b/repo2docker/contentproviders/hydroshare.py
index 1cb8b697..3378129a 100755
--- a/repo2docker/contentproviders/hydroshare.py
+++ b/repo2docker/contentproviders/hydroshare.py
@@ -61,7 +61,7 @@ class Hydroshare(DoiProvider):
 
         bag_url = "{}{}".format(host["django_irods"], resource_id)
 
-        yield "Downloading {}.\n".format(bag_url)
+        yield f"Downloading {bag_url}.\n"
 
         # bag downloads are prepared on demand and may need some time
         conn = self.urlopen(bag_url)
@@ -82,7 +82,7 @@ class Hydroshare(DoiProvider):
             time.sleep(wait_time)
             conn = self.urlopen(bag_url)
         if conn.status_code != 200:
-            msg = "Failed to download bag. status code {}.\n".format(conn.status_code)
+            msg = f"Failed to download bag. status code {conn.status_code}.\n"
             yield msg
             raise ContentProviderException(msg)
         # Bag creation seems to need a small time buffer after it says it's ready.
@@ -102,4 +102,4 @@ class Hydroshare(DoiProvider):
     @property
     def content_id(self):
         """The HydroShare resource ID"""
-        return "{}.v{}".format(self.resource_id, self.version)
+        return f"{self.resource_id}.v{self.version}"
diff --git a/repo2docker/contentproviders/mercurial.py b/repo2docker/contentproviders/mercurial.py
index 60d5f2fd..e29584f2 100644
--- a/repo2docker/contentproviders/mercurial.py
+++ b/repo2docker/contentproviders/mercurial.py
@@ -41,8 +41,7 @@ class Mercurial(ContentProvider):
                 # don't update so the clone will include an empty working
                 # directory, the given ref will be updated out later
                 cmd.extend(["--noupdate"])
-            for line in execute_cmd(cmd, capture=yield_output):
-                yield line
+            yield from execute_cmd(cmd, capture=yield_output)
 
         except subprocess.CalledProcessError as error:
             msg = f"Failed to clone repository from {repo}"
@@ -54,17 +53,16 @@ class Mercurial(ContentProvider):
         # check out the specific ref given by the user
         if ref is not None:
             try:
-                for line in execute_cmd(
+                yield from execute_cmd(
                     ["hg", "update", "--clean", ref] + args_enabling_topic,
                     cwd=output_dir,
                     capture=yield_output,
-                ):
-                    yield line
+                )
             except subprocess.CalledProcessError:
                 self.log.error(
                     "Failed to update to ref %s", ref, extra=dict(phase=R2dState.FAILED)
                 )
-                raise ValueError("Failed to update to ref {}".format(ref))
+                raise ValueError(f"Failed to update to ref {ref}")
 
         cmd = ["hg", "identify", "-i"] + args_enabling_topic
         sha1 = subprocess.Popen(cmd, stdout=subprocess.PIPE, cwd=output_dir)
diff --git a/repo2docker/contentproviders/swhid.py b/repo2docker/contentproviders/swhid.py
index e2050177..2a964e70 100644
--- a/repo2docker/contentproviders/swhid.py
+++ b/repo2docker/contentproviders/swhid.py
@@ -34,12 +34,12 @@ class Swhid(ContentProvider):
         self.session = requests.Session()
         self.session.headers.update(
             {
-                "user-agent": "repo2docker {}".format(__version__),
+                "user-agent": f"repo2docker {__version__}",
             }
         )
 
     def set_auth_token(self, token):
-        header = {"Authorization": "Bearer {}".format(token)}
+        header = {"Authorization": f"Bearer {token}"}
         self.session.headers.update(header)
 
     def _request(self, url, method="GET"):
@@ -72,8 +72,8 @@ class Swhid(ContentProvider):
             return {"swhid": swhid, "swhid_obj": swhid_dict}
 
     def fetch_directory(self, dir_hash, output_dir):
-        url = "{}/vault/directory/{}/".format(self.base_url, dir_hash)
-        yield "Fetching directory {} from {}\n".format(dir_hash, url)
+        url = f"{self.base_url}/vault/directory/{dir_hash}/"
+        yield f"Fetching directory {dir_hash} from {url}\n"
         resp = self._request(url, "POST")
         receipt = resp.json()
         status = receipt["status"]
@@ -92,7 +92,7 @@ class Swhid(ContentProvider):
         # move its content one level up
         copytree(path.join(output_dir, dir_hash), output_dir)
         shutil.rmtree(path.join(output_dir, dir_hash))
-        yield "Fetched files: {}\n".format(os.listdir(output_dir))
+        yield f"Fetched files: {os.listdir(output_dir)}\n"
 
     def fetch(self, spec, output_dir, yield_output=False):
         swhid = spec["swhid"]
@@ -101,12 +101,12 @@ class Swhid(ContentProvider):
         if swhid_obj["type"] == "rev":
             # need to get the directory for this revision
             sha1git = swhid_obj["hash"]
-            url = "{}/revision/{}/".format(self.base_url, sha1git)
-            yield "Fetching revision {} from {}\n".format(sha1git, url)
+            url = f"{self.base_url}/revision/{sha1git}/"
+            yield f"Fetching revision {sha1git} from {url}\n"
             resp = self._request(url)
             assert resp.ok, (resp.content, self.session.headers)
             directory = resp.json()["directory"]
-            self.swhid = "swh:1:dir:{}".format(directory)
+            self.swhid = f"swh:1:dir:{directory}"
             yield from self.fetch_directory(directory, output_dir)
         elif swhid_obj["type"] == "dir":
             self.swhid = swhid
diff --git a/repo2docker/contentproviders/zenodo.py b/repo2docker/contentproviders/zenodo.py
index 7a5d0932..a58e295f 100644
--- a/repo2docker/contentproviders/zenodo.py
+++ b/repo2docker/contentproviders/zenodo.py
@@ -66,7 +66,7 @@ class Zenodo(DoiProvider):
         record_id = spec["record"]
         host = spec["host"]
 
-        yield "Fetching Zenodo record {}.\n".format(record_id)
+        yield f"Fetching Zenodo record {record_id}.\n"
         resp = self.urlopen(
             "{}{}".format(host["api"], record_id),
             headers={"accept": "application/json"},
@@ -77,10 +77,7 @@ class Zenodo(DoiProvider):
         files = deep_get(record, host["filepath"])
         only_one_file = len(files) == 1
         for file_ref in files:
-            for line in self.fetch_file(
-                file_ref, host, output_dir, unzip=only_one_file
-            ):
-                yield line
+            yield from self.fetch_file(file_ref, host, output_dir, unzip=only_one_file)
 
     @property
     def content_id(self):
diff --git a/repo2docker/engine.py b/repo2docker/engine.py
index 9b5e92eb..459b2be8 100644
--- a/repo2docker/engine.py
+++ b/repo2docker/engine.py
@@ -131,7 +131,7 @@ class Image:
         return self._config
 
     def __repr__(self):
-        return "Image(tags={},config={})".format(self.tags, self.config)
+        return f"Image(tags={self.tags},config={self.config})"
 
 
 class ContainerEngine(LoggingConfigurable):
diff --git a/tests/conftest.py b/tests/conftest.py
index 19c0ca6e..eda58223 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -212,7 +212,7 @@ class Repo2DockerTest(pytest.Function):
         err = excinfo.value
         if isinstance(err, SystemExit):
             cmd = "jupyter-repo2docker %s" % " ".join(map(pipes.quote, self.args))
-            return "%s | exited with status=%s" % (cmd, err.code)
+            return f"{cmd} | exited with status={err.code}"
         else:
             return super().repr_failure(excinfo)
 
diff --git a/tests/memlimit/dockerfile/postBuild b/tests/memlimit/dockerfile/postBuild
index af9f9a3b..4fe5360f 100755
--- a/tests/memlimit/dockerfile/postBuild
+++ b/tests/memlimit/dockerfile/postBuild
@@ -20,7 +20,7 @@ with open("mem_allocate_mb") as f:
     mem_allocate_mb = int(f.read().strip())
 
 size = 1024 * 1024 * mem_allocate_mb
-print("trying to allocate {}MB".format(mem_allocate_mb))
+print(f"trying to allocate {mem_allocate_mb}MB")
 
 ret = libc.malloc(size)
 
diff --git a/tests/memlimit/non-dockerfile/postBuild b/tests/memlimit/non-dockerfile/postBuild
index af9f9a3b..4fe5360f 100755
--- a/tests/memlimit/non-dockerfile/postBuild
+++ b/tests/memlimit/non-dockerfile/postBuild
@@ -20,7 +20,7 @@ with open("mem_allocate_mb") as f:
     mem_allocate_mb = int(f.read().strip())
 
 size = 1024 * 1024 * mem_allocate_mb
-print("trying to allocate {}MB".format(mem_allocate_mb))
+print(f"trying to allocate {mem_allocate_mb}MB")
 
 ret = libc.malloc(size)
 
diff --git a/tests/unit/contentproviders/test_dataverse.py b/tests/unit/contentproviders/test_dataverse.py
index 3d912a7b..63a58471 100644
--- a/tests/unit/contentproviders/test_dataverse.py
+++ b/tests/unit/contentproviders/test_dataverse.py
@@ -12,8 +12,8 @@ from repo2docker.contentproviders import Dataverse
 
 
 test_dv = Dataverse()
-harvard_dv = next((_ for _ in test_dv.hosts if _["name"] == "Harvard Dataverse"))
-cimmyt_dv = next((_ for _ in test_dv.hosts if _["name"] == "CIMMYT Research Data"))
+harvard_dv = next(_ for _ in test_dv.hosts if _["name"] == "Harvard Dataverse")
+cimmyt_dv = next(_ for _ in test_dv.hosts if _["name"] == "CIMMYT Research Data")
 test_hosts = [
     (
         [
@@ -153,7 +153,7 @@ def test_dataverse_fetch(dv_files, requests_mock):
         for l in dv.fetch(spec, d):
             output.append(l)
         unpacked_files = set(os.listdir(d))
-        expected = set(["directory", "some-file.txt"])
+        expected = {"directory", "some-file.txt"}
         assert expected == unpacked_files
         assert os.path.isfile(
             os.path.join(d, "directory", "subdirectory", "the-other-file.txt")
diff --git a/tests/unit/contentproviders/test_doi.py b/tests/unit/contentproviders/test_doi.py
index dbe39160..ed2dcb73 100644
--- a/tests/unit/contentproviders/test_doi.py
+++ b/tests/unit/contentproviders/test_doi.py
@@ -27,7 +27,7 @@ def test_url_headers(requests_mock):
     result = doi.urlopen("https://mybinder.org", headers=headers)
     assert "test1" in result.request.headers
     assert "Test2" in result.request.headers
-    assert result.request.headers["User-Agent"] == "repo2docker {}".format(__version__)
+    assert result.request.headers["User-Agent"] == f"repo2docker {__version__}"
 
 
 def test_unresolving_doi():
diff --git a/tests/unit/contentproviders/test_figshare.py b/tests/unit/contentproviders/test_figshare.py
index 7d29fbcb..3de67e98 100644
--- a/tests/unit/contentproviders/test_figshare.py
+++ b/tests/unit/contentproviders/test_figshare.py
@@ -113,8 +113,8 @@ def test_detect_not_figshare():
 def figshare_archive(prefix="a_directory"):
     with NamedTemporaryFile(suffix=".zip") as zfile:
         with ZipFile(zfile.name, mode="w") as zip:
-            zip.writestr("{}/some-file.txt".format(prefix), "some content")
-            zip.writestr("{}/some-other-file.txt".format(prefix), "some more content")
+            zip.writestr(f"{prefix}/some-file.txt", "some content")
+            zip.writestr(f"{prefix}/some-other-file.txt", "some more content")
 
         yield zfile.name
 
@@ -127,7 +127,7 @@ def test_fetch_zip(requests_mock):
                 {
                     "name": "afake.zip",
                     "is_link_only": False,
-                    "download_url": "file://{}".format(fig_path),
+                    "download_url": f"file://{fig_path}",
                 }
             ]
         }
@@ -135,9 +135,7 @@ def test_fetch_zip(requests_mock):
             "https://api.figshare.com/v2/articles/123456/versions/42",
             json=mock_response,
         )
-        requests_mock.get(
-            "file://{}".format(fig_path), content=open(fig_path, "rb").read()
-        )
+        requests_mock.get(f"file://{fig_path}", content=open(fig_path, "rb").read())
 
         # with patch.object(Figshare, "urlopen", new=mock_urlopen):
         with TemporaryDirectory() as d:
@@ -146,7 +144,7 @@ def test_fetch_zip(requests_mock):
                 output.append(l)
 
             unpacked_files = set(os.listdir(d))
-            expected = set(["some-other-file.txt", "some-file.txt"])
+            expected = {"some-other-file.txt", "some-file.txt"}
             assert expected == unpacked_files
 
 
@@ -157,12 +155,12 @@ def test_fetch_data(requests_mock):
                 "files": [
                     {
                         "name": "afake.file",
-                        "download_url": "file://{}".format(a_path),
+                        "download_url": f"file://{a_path}",
                         "is_link_only": False,
                     },
                     {
                         "name": "bfake.data",
-                        "download_url": "file://{}".format(b_path),
+                        "download_url": f"file://{b_path}",
                         "is_link_only": False,
                     },
                     {"name": "cfake.link", "is_link_only": True},
@@ -173,12 +171,8 @@ def test_fetch_data(requests_mock):
                 "https://api.figshare.com/v2/articles/123456/versions/42",
                 json=mock_response,
             )
-            requests_mock.get(
-                "file://{}".format(a_path), content=open(a_path, "rb").read()
-            )
-            requests_mock.get(
-                "file://{}".format(b_path), content=open(b_path, "rb").read()
-            )
+            requests_mock.get(f"file://{a_path}", content=open(a_path, "rb").read())
+            requests_mock.get(f"file://{b_path}", content=open(b_path, "rb").read())
 
             with TemporaryDirectory() as d:
                 output = []
diff --git a/tests/unit/contentproviders/test_hydroshare.py b/tests/unit/contentproviders/test_hydroshare.py
index da80905f..b0211c52 100755
--- a/tests/unit/contentproviders/test_hydroshare.py
+++ b/tests/unit/contentproviders/test_hydroshare.py
@@ -103,8 +103,8 @@ def test_detect_hydroshare(requests_mock):
 def hydroshare_archive(prefix="b8f6eae9d89241cf8b5904033460af61/data/contents"):
     with NamedTemporaryFile(suffix=".zip") as zfile:
         with ZipFile(zfile.name, mode="w") as zip:
-            zip.writestr("{}/some-file.txt".format(prefix), "some content")
-            zip.writestr("{}/some-other-file.txt".format(prefix), "some more content")
+            zip.writestr(f"{prefix}/some-file.txt", "some content")
+            zip.writestr(f"{prefix}/some-other-file.txt", "some more content")
 
         yield zfile
 
@@ -149,7 +149,7 @@ def test_fetch_bag():
                         output.append(l)
 
                     unpacked_files = set(os.listdir(d))
-                    expected = set(["some-other-file.txt", "some-file.txt"])
+                    expected = {"some-other-file.txt", "some-file.txt"}
                     assert expected == unpacked_files
 
 
diff --git a/tests/unit/contentproviders/test_swhid.py b/tests/unit/contentproviders/test_swhid.py
index 953218e3..48c1fa31 100644
--- a/tests/unit/contentproviders/test_swhid.py
+++ b/tests/unit/contentproviders/test_swhid.py
@@ -99,7 +99,7 @@ def mocked_provider(tmpdir, dirhash, tarfile_buf):
 
     adapter.register_uri(
         "GET",
-        "mock://api/1/revision/{}/".format(NULLID),
+        f"mock://api/1/revision/{NULLID}/",
         json={
             "author": {"fullname": "John Doe <jdoe@example.com>"},
             "directory": dirhash,
@@ -107,25 +107,25 @@ def mocked_provider(tmpdir, dirhash, tarfile_buf):
     )
     adapter.register_uri(
         "POST",
-        "mock://api/1/vault/directory/{}/".format(dirhash),
+        f"mock://api/1/vault/directory/{dirhash}/",
         json={
-            "fetch_url": "mock://api/1/vault/directory/{}/raw/".format(dirhash),
+            "fetch_url": f"mock://api/1/vault/directory/{dirhash}/raw/",
             "status": "new",
         },
     )
     adapter.register_uri(
         "GET",
-        "mock://api/1/vault/directory/{}/".format(dirhash),
+        f"mock://api/1/vault/directory/{dirhash}/",
         [
             {
                 "json": {
-                    "fetch_url": "mock://api/1/vault/directory/{}/raw/".format(dirhash),
+                    "fetch_url": f"mock://api/1/vault/directory/{dirhash}/raw/",
                     "status": "pending",
                 }
             },
             {
                 "json": {
-                    "fetch_url": "mock://api/1/vault/directory/{}/raw/".format(dirhash),
+                    "fetch_url": f"mock://api/1/vault/directory/{dirhash}/raw/",
                     "status": "done",
                 }
             },
@@ -133,7 +133,7 @@ def mocked_provider(tmpdir, dirhash, tarfile_buf):
     )
     adapter.register_uri(
         "GET",
-        "mock://api/1/vault/directory/{}/raw/".format(dirhash),
+        f"mock://api/1/vault/directory/{dirhash}/raw/",
         content=tarfile_buf,
     )
     return provider
diff --git a/tests/unit/contentproviders/test_zenodo.py b/tests/unit/contentproviders/test_zenodo.py
index c46cf8d9..88e143c6 100644
--- a/tests/unit/contentproviders/test_zenodo.py
+++ b/tests/unit/contentproviders/test_zenodo.py
@@ -82,8 +82,8 @@ def test_detect_zenodo(test_input, expected, requests_mock):
 def zenodo_archive(prefix="a_directory"):
     with NamedTemporaryFile(suffix=".zip") as zfile:
         with ZipFile(zfile.name, mode="w") as zip:
-            zip.writestr("{}/some-file.txt".format(prefix), "some content")
-            zip.writestr("{}/some-other-file.txt".format(prefix), "some more content")
+            zip.writestr(f"{prefix}/some-file.txt", "some content")
+            zip.writestr(f"{prefix}/some-other-file.txt", "some more content")
 
         yield zfile.name
 
@@ -96,15 +96,13 @@ def test_fetch_software_from_github_archive(requests_mock):
             "files": [
                 {
                     "filename": "some_dir/afake.zip",
-                    "links": {"download": "file://{}".format(zen_path)},
+                    "links": {"download": f"file://{zen_path}"},
                 }
             ],
             "metadata": {"upload_type": "other"},
         }
         requests_mock.get("https://zenodo.org/api/records/1234", json=mock_response)
-        requests_mock.get(
-            "file://{}".format(zen_path), content=open(zen_path, "rb").read()
-        )
+        requests_mock.get(f"file://{zen_path}", content=open(zen_path, "rb").read())
 
         zen = Zenodo()
         spec = {"host": test_zen.hosts[1], "record": "1234"}
@@ -115,7 +113,7 @@ def test_fetch_software_from_github_archive(requests_mock):
                 output.append(l)
 
             unpacked_files = set(os.listdir(d))
-            expected = set(["some-other-file.txt", "some-file.txt"])
+            expected = {"some-other-file.txt", "some-file.txt"}
             assert expected == unpacked_files
 
 
@@ -129,15 +127,13 @@ def test_fetch_software(requests_mock):
                     # this is the difference to the GitHub generated one,
                     # the ZIP file isn't in a directory
                     "filename": "afake.zip",
-                    "links": {"download": "file://{}".format(zen_path)},
+                    "links": {"download": f"file://{zen_path}"},
                 }
             ],
             "metadata": {"upload_type": "software"},
         }
         requests_mock.get("https://zenodo.org/api/records/1234", json=mock_response)
-        requests_mock.get(
-            "file://{}".format(zen_path), content=open(zen_path, "rb").read()
-        )
+        requests_mock.get(f"file://{zen_path}", content=open(zen_path, "rb").read())
 
         with TemporaryDirectory() as d:
             zen = Zenodo()
@@ -147,7 +143,7 @@ def test_fetch_software(requests_mock):
                 output.append(l)
 
             unpacked_files = set(os.listdir(d))
-            expected = set(["some-other-file.txt", "some-file.txt"])
+            expected = {"some-other-file.txt", "some-file.txt"}
             assert expected == unpacked_files
 
 
@@ -159,21 +155,21 @@ def test_fetch_data(requests_mock):
                 "files": [
                     {
                         "filename": "afake.zip",
-                        "links": {"download": "file://{}".format(a_zen_path)},
+                        "links": {"download": f"file://{a_zen_path}"},
                     },
                     {
                         "filename": "bfake.zip",
-                        "links": {"download": "file://{}".format(b_zen_path)},
+                        "links": {"download": f"file://{b_zen_path}"},
                     },
                 ],
                 "metadata": {"upload_type": "data"},
             }
             requests_mock.get("https://zenodo.org/api/records/1234", json=mock_response)
             requests_mock.get(
-                "file://{}".format(a_zen_path), content=open(a_zen_path, "rb").read()
+                f"file://{a_zen_path}", content=open(a_zen_path, "rb").read()
             )
             requests_mock.get(
-                "file://{}".format(b_zen_path), content=open(b_zen_path, "rb").read()
+                f"file://{b_zen_path}", content=open(b_zen_path, "rb").read()
             )
 
             with TemporaryDirectory() as d:
diff --git a/tests/unit/test_args.py b/tests/unit/test_args.py
index e5fd2c1a..404ee796 100644
--- a/tests/unit/test_args.py
+++ b/tests/unit/test_args.py
@@ -13,7 +13,7 @@ def test_version(capsys):
     """
     with pytest.raises(SystemExit):
         make_r2d(["--version"])
-    assert capsys.readouterr().out == "{}\n".format(__version__)
+    assert capsys.readouterr().out == f"{__version__}\n"
 
 
 def test_simple():
diff --git a/tests/unit/test_connect_url.py b/tests/unit/test_connect_url.py
index 681cc680..3115a8ab 100644
--- a/tests/unit/test_connect_url.py
+++ b/tests/unit/test_connect_url.py
@@ -40,8 +40,8 @@ def test_connect_url(tmpdir):
     app.start()
     container = app.start_container()
 
-    container_url = "http://{}:{}/api".format(app.hostname, app.port)
-    expected_url = "http://{}:{}".format(app.hostname, app.port)
+    container_url = f"http://{app.hostname}:{app.port}/api"
+    expected_url = f"http://{app.hostname}:{app.port}"
 
     # wait a bit for the container to be ready
     # give the container a chance to start
diff --git a/tests/unit/test_env.py b/tests/unit/test_env.py
index ee01b361..fde4aed4 100644
--- a/tests/unit/test_env.py
+++ b/tests/unit/test_env.py
@@ -30,7 +30,7 @@ def test_env(capfd):
                 "repo2docker",
                 # 'key=value' are exported as is in docker
                 "-e",
-                "FOO={}".format(ts),
+                f"FOO={ts}",
                 "--env",
                 "BAR=baz",
                 # 'key' is exported with the currently exported value
@@ -65,7 +65,7 @@ def test_env(capfd):
 
     # stderr should contain lines of output
     declares = [x for x in captured.err.splitlines() if x.startswith("declare")]
-    assert 'declare -x FOO="{}"'.format(ts) in declares
+    assert f'declare -x FOO="{ts}"' in declares
     assert 'declare -x BAR="baz"' in declares
     assert 'declare -x SPAM="eggs"' in declares
     assert "declare -x NO_SPAM" not in declares
diff --git a/tests/unit/test_ports.py b/tests/unit/test_ports.py
index 09944e87..90148ba4 100644
--- a/tests/unit/test_ports.py
+++ b/tests/unit/test_ports.py
@@ -82,13 +82,13 @@ def read_port_mapping_response(
     if all_ports:
         port = port_mapping["8888/tcp"][0]["HostPort"]
 
-    url = "http://{}:{}".format(host, port)
+    url = f"http://{host}:{port}"
     for i in range(5):
         try:
             r = requests.get(url)
             r.raise_for_status()
         except Exception as e:
-            print("No response from {}: {}".format(url, e))
+            print(f"No response from {url}: {e}")
             container.reload()
             assert container.status == "running"
             time.sleep(3)
diff --git a/tests/unit/test_r.py b/tests/unit/test_r.py
index f13ee739..3d141cfc 100644
--- a/tests/unit/test_r.py
+++ b/tests/unit/test_r.py
@@ -87,6 +87,7 @@ def test_snapshot_mran_date(requested, expected):
 
     with patch("requests.head", side_effect=mock_request_head):
         r = buildpacks.RBuildPack()
-        assert r.get_mran_snapshot_url(
-            requested
-        ) == "https://mran.microsoft.com/snapshot/{}".format(expected.isoformat())
+        assert (
+            r.get_mran_snapshot_url(requested)
+            == f"https://mran.microsoft.com/snapshot/{expected.isoformat()}"
+        )
diff --git a/tests/unit/test_users.py b/tests/unit/test_users.py
index 2bceb5ff..e14eeaf1 100644
--- a/tests/unit/test_users.py
+++ b/tests/unit/test_users.py
@@ -35,7 +35,7 @@ def test_user():
             [
                 "repo2docker",
                 "-v",
-                "{}:/home/{}".format(tmpdir, username),
+                f"{tmpdir}:/home/{username}",
                 "--user-id",
                 userid,
                 "--user-name",
@@ -53,7 +53,7 @@ def test_user():
         with open(os.path.join(tmpdir, "id")) as f:
             assert f.read().strip() == userid
         with open(os.path.join(tmpdir, "pwd")) as f:
-            assert f.read().strip() == "/home/{}".format(username)
+            assert f.read().strip() == f"/home/{username}"
         with open(os.path.join(tmpdir, "name")) as f:
             assert f.read().strip() == username
         with open(os.path.join(tmpdir, "name")) as f:
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index ef9a8d38..28401e33 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -90,7 +90,7 @@ def test_invalid_port_mapping(port_spec):
     with pytest.raises(ValueError) as e:
         utils.validate_and_generate_port_mapping([port_spec])
 
-    assert 'Port specification "{}"'.format(port_spec) in str(e.value)
+    assert f'Port specification "{port_spec}"' in str(e.value)
 
 
 def test_deep_get():
diff --git a/tests/unit/test_volumes.py b/tests/unit/test_volumes.py
index db6efba2..9e108ec8 100644
--- a/tests/unit/test_volumes.py
+++ b/tests/unit/test_volumes.py
@@ -22,7 +22,7 @@ def test_volume_abspath():
             [
                 "repo2docker",
                 "-v",
-                "{}:/home/{}".format(tmpdir, username),
+                f"{tmpdir}:/home/{username}",
                 "--user-id",
                 str(os.geteuid()),
                 "--user-name",
@@ -31,7 +31,7 @@ def test_volume_abspath():
                 "--",
                 "/bin/bash",
                 "-c",
-                "echo -n {} > ts".format(ts),
+                f"echo -n {ts} > ts",
             ]
         )
 
@@ -61,7 +61,7 @@ def test_volume_relpath():
                     "--",
                     "/bin/bash",
                     "-c",
-                    "echo -n {} > ts".format(ts),
+                    f"echo -n {ts} > ts",
                 ]
             )
 
diff --git a/versioneer.py b/versioneer.py
index 2b545405..a4708899 100644
--- a/versioneer.py
+++ b/versioneer.py
@@ -275,7 +275,6 @@ https://creativecommons.org/publicdomain/zero/1.0/ .
 
 """
 
-from __future__ import print_function
 
 try:
     import configparser
@@ -344,7 +343,7 @@ def get_config_from_root(root):
     # the top of versioneer.py for instructions on writing your setup.cfg .
     setup_cfg = os.path.join(root, "setup.cfg")
     parser = configparser.SafeConfigParser()
-    with open(setup_cfg, "r") as f:
+    with open(setup_cfg) as f:
         parser.readfp(f)
     VCS = parser.get("versioneer", "VCS")  # mandatory
 
@@ -404,7 +403,7 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False, env=
                 stderr=(subprocess.PIPE if hide_stderr else None),
             )
             break
-        except EnvironmentError:
+        except OSError:
             e = sys.exc_info()[1]
             if e.errno == errno.ENOENT:
                 continue
@@ -414,7 +413,7 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False, env=
             return None, None
     else:
         if verbose:
-            print("unable to find command, tried %s" % (commands,))
+            print(f"unable to find command, tried {commands}")
         return None, None
     stdout = p.communicate()[0].strip()
     if sys.version_info[0] >= 3:
@@ -429,7 +428,7 @@ def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False, env=
 
 LONG_VERSION_PY[
     "git"
-] = '''
+] = r'''
 # This file helps to compute a version number in source trees obtained from
 # git-archive tarball (such as those provided by githubs download-from-tag
 # feature). Distribution tarballs (built by setup.py sdist) and build
@@ -961,7 +960,7 @@ def git_get_keywords(versionfile_abs):
     # _version.py.
     keywords = {}
     try:
-        f = open(versionfile_abs, "r")
+        f = open(versionfile_abs)
         for line in f.readlines():
             if line.strip().startswith("git_refnames ="):
                 mo = re.search(r'=\s*"(.*)"', line)
@@ -976,7 +975,7 @@ def git_get_keywords(versionfile_abs):
                 if mo:
                     keywords["date"] = mo.group(1)
         f.close()
-    except EnvironmentError:
+    except OSError:
         pass
     return keywords
 
@@ -1000,11 +999,11 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         if verbose:
             print("keywords are unexpanded, not using")
         raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
-    refs = set([r.strip() for r in refnames.strip("()").split(",")])
+    refs = {r.strip() for r in refnames.strip("()").split(",")}
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
     TAG = "tag: "
-    tags = set([r[len(TAG) :] for r in refs if r.startswith(TAG)])
+    tags = {r[len(TAG) :] for r in refs if r.startswith(TAG)}
     if not tags:
         # Either we're using git < 1.8.3, or there really are no tags. We use
         # a heuristic: assume all version tags have a digit. The old git %d
@@ -1013,7 +1012,7 @@ def git_versions_from_keywords(keywords, tag_prefix, verbose):
         # between branches and tags. By ignoring refnames without digits, we
         # filter out many common branch names like "release" and
         # "stabilization", as well as "HEAD" and "master".
-        tags = set([r for r in refs if re.search(r"\d", r)])
+        tags = {r for r in refs if re.search(r"\d", r)}
         if verbose:
             print("discarding '%s', no digits" % ",".join(refs - tags))
     if verbose:
@@ -1116,7 +1115,7 @@ def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
             if verbose:
                 fmt = "tag '%s' doesn't start with prefix '%s'"
                 print(fmt % (full_tag, tag_prefix))
-            pieces["error"] = "tag '%s' doesn't start with prefix '%s'" % (
+            pieces["error"] = "tag '{}' doesn't start with prefix '{}'".format(
                 full_tag,
                 tag_prefix,
             )
@@ -1166,13 +1165,13 @@ def do_vcs_install(manifest_in, versionfile_source, ipy):
     files.append(versioneer_file)
     present = False
     try:
-        f = open(".gitattributes", "r")
+        f = open(".gitattributes")
         for line in f.readlines():
             if line.strip().startswith(versionfile_source):
                 if "export-subst" in line.strip().split()[1:]:
                     present = True
         f.close()
-    except EnvironmentError:
+    except OSError:
         pass
     if not present:
         f = open(".gitattributes", "a+")
@@ -1236,7 +1235,7 @@ def versions_from_file(filename):
     try:
         with open(filename) as f:
             contents = f.read()
-    except EnvironmentError:
+    except OSError:
         raise NotThisMethod("unable to read _version.py")
     mo = re.search(
         r"version_json = '''\n(.*)'''  # END VERSION_JSON", contents, re.M | re.S
@@ -1257,7 +1256,7 @@ def write_to_version_file(filename, versions):
     with open(filename, "w") as f:
         f.write(SHORT_VERSION_PY % contents)
 
-    print("set %s to '%s'" % (filename, versions["version"]))
+    print("set {} to '{}'".format(filename, versions["version"]))
 
 
 def plus_or_dot(pieces):
@@ -1482,7 +1481,7 @@ def get_versions(verbose=False):
     try:
         ver = versions_from_file(versionfile_abs)
         if verbose:
-            print("got version from file %s %s" % (versionfile_abs, ver))
+            print(f"got version from file {versionfile_abs} {ver}")
         return ver
     except NotThisMethod:
         pass
@@ -1755,11 +1754,7 @@ def do_setup():
     root = get_root()
     try:
         cfg = get_config_from_root(root)
-    except (
-        EnvironmentError,
-        configparser.NoSectionError,
-        configparser.NoOptionError,
-    ) as e:
+    except (OSError, configparser.NoSectionError, configparser.NoOptionError) as e:
         if isinstance(e, (EnvironmentError, configparser.NoSectionError)):
             print("Adding sample versioneer config to setup.cfg", file=sys.stderr)
             with open(os.path.join(root, "setup.cfg"), "a") as f:
@@ -1784,9 +1779,9 @@ def do_setup():
     ipy = os.path.join(os.path.dirname(cfg.versionfile_source), "__init__.py")
     if os.path.exists(ipy):
         try:
-            with open(ipy, "r") as f:
+            with open(ipy) as f:
                 old = f.read()
-        except EnvironmentError:
+        except OSError:
             old = ""
         if INIT_PY_SNIPPET not in old:
             print(" appending to %s" % ipy)
@@ -1805,12 +1800,12 @@ def do_setup():
     manifest_in = os.path.join(root, "MANIFEST.in")
     simple_includes = set()
     try:
-        with open(manifest_in, "r") as f:
+        with open(manifest_in) as f:
             for line in f:
                 if line.startswith("include "):
                     for include in line.split()[1:]:
                         simple_includes.add(include)
-    except EnvironmentError:
+    except OSError:
         pass
     # That doesn't cover everything MANIFEST.in can do
     # (http://docs.python.org/2/distutils/sourcedist.html#commands), so
@@ -1844,7 +1839,7 @@ def scan_setup_py():
     found = set()
     setters = False
     errors = 0
-    with open("setup.py", "r") as f:
+    with open("setup.py") as f:
         for line in f.readlines():
             if "import versioneer" in line:
                 found.add("import")