diff --git a/test/initrd.py b/test/initrd.py
index 5f6e4879..8d6a3e76 100644
--- a/test/initrd.py
+++ b/test/initrd.py
@@ -168,7 +168,7 @@ class Initrd:
                                          encoding=None,
                                          stdin=image,
                                          stderr=subprocess.DEVNULL)
-        return output.strip().decode('utf-8')
+        return output.strip().decode('utf8')
 
 
 def read_initrd(path):
diff --git a/test/mod/test_buildroot.py b/test/mod/test_buildroot.py
index fd0b28c6..26209bb4 100644
--- a/test/mod/test_buildroot.py
+++ b/test/mod/test_buildroot.py
@@ -55,14 +55,14 @@ def test_runner_fail(tempdir):
     logfile = os.path.join(tempdir, "log.txt")
 
     with BuildRoot("/", runner, libdir, var) as root, \
-            open(logfile, "w") as log:
+            open(logfile, "w", encoding="utf8") as log:
 
         monitor = LogMonitor(log.fileno())
 
         r = root.run(["/usr/bin/true"], monitor)
 
     assert r.returncode == 1
-    with open(logfile) as f:
+    with open(logfile, encoding="utf8") as f:
         log = f.read()
     assert log
     assert r.output
@@ -208,7 +208,7 @@ def test_env_isolation(tempdir):
         r = root.run(cmd, monitor, binds=[f"{ipc}:/ipc"])
 
     assert r.returncode == 0
-    with open(os.path.join(ipc, "env.txt")) as f:
+    with open(os.path.join(ipc, "env.txt"), encoding="utf8") as f:
         data = f.read().strip()
     assert data
     have = dict(map(lambda x: x.split("=", 1), data.split("\n")))
@@ -247,7 +247,7 @@ def test_caps(tempdir):
             r = root.run(cmd, monitor, binds=[f"{ipc}:/ipc"])
 
             assert r.returncode == 0
-            with open(os.path.join(ipc, "status"), encoding="utf-8") as f:
+            with open(os.path.join(ipc, "status"), encoding="utf8") as f:
                 data = f.readlines()
             assert data
 
diff --git a/test/mod/test_monitor.py b/test/mod/test_monitor.py
index b9fc6dfc..fb1dcce8 100644
--- a/test/mod/test_monitor.py
+++ b/test/mod/test_monitor.py
@@ -67,13 +67,13 @@ class TestMonitor(unittest.TestCase):
 
             logfile = os.path.join(tmpdir, "log.txt")
 
-            with open(logfile, "w") as log, ObjectStore(storedir) as store:
+            with open(logfile, "w", encoding="utf8") as log, ObjectStore(storedir) as store:
                 monitor = LogMonitor(log.fileno())
                 res = pipeline.run(store,
                                    monitor,
                                    libdir=os.path.abspath(os.curdir))
 
-                with open(logfile) as f:
+                with open(logfile, encoding="utf8") as f:
                     log = f.read()
 
             assert res
diff --git a/test/mod/test_objectstore.py b/test/mod/test_objectstore.py
index 4063fa10..13fe8daa 100644
--- a/test/mod/test_objectstore.py
+++ b/test/mod/test_objectstore.py
@@ -122,7 +122,7 @@ class TestObjectStore(unittest.TestCase):
             with object_store.new() as tree:
                 path = tree.write()
                 with tree.write() as path, \
-                        open(os.path.join(path, "data"), "w") as f:
+                        open(os.path.join(path, "data"), "w", encoding="utf8") as f:
                     f.write(data)
                     st = os.fstat(f.fileno())
                     data_inode = st.st_ino
@@ -134,7 +134,7 @@ class TestObjectStore(unittest.TestCase):
                 # check that "data" is still the very
                 # same file after committing
                 with tree.read() as path:
-                    with open(os.path.join(path, "data"), "r") as f:
+                    with open(os.path.join(path, "data"), "r", encoding="utf8") as f:
                         st = os.fstat(f.fileno())
                         self.assertEqual(st.st_ino, data_inode)
                         data_read = f.read()
@@ -147,7 +147,7 @@ class TestObjectStore(unittest.TestCase):
             with object_store.new(base_id="x") as tree:
                 self.assertEqual(tree.base, "x")
                 with tree.read() as path:
-                    with open(os.path.join(path, "data"), "r") as f:
+                    with open(os.path.join(path, "data"), "r", encoding="utf8") as f:
                         # copy-on-write: since we have not written
                         # to the tree yet, "data" should be the
                         # very same file as that one of object "x"
@@ -303,7 +303,7 @@ class TestObjectStore(unittest.TestCase):
             assert Path(path) == mountpoint
             filepath = Path(mountpoint, "file.txt")
             assert filepath.exists()
-            txt = filepath.read_text()
+            txt = filepath.read_text(encoding="utf8")
             assert txt == "osbuild"
 
             # check we can mount subtrees via `read_tree_at`
@@ -314,7 +314,7 @@ class TestObjectStore(unittest.TestCase):
             path = client.read_tree_at("42", filemount, "/file.txt")
             filepath = Path(path)
             assert filepath.is_file()
-            txt = filepath.read_text()
+            txt = filepath.read_text(encoding="utf8")
             assert txt == "osbuild"
 
             dirmount = Path(tmpdir, "dir")
diff --git a/test/mod/test_util_linux.py b/test/mod/test_util_linux.py
index fd7a99d0..2838dc66 100644
--- a/test/mod/test_util_linux.py
+++ b/test/mod/test_util_linux.py
@@ -26,7 +26,7 @@ def test_ioctl_get_immutable(tmpdir):
     # as intended.
     #
 
-    with open(f"{tmpdir}/immutable", "x") as f:
+    with open(f"{tmpdir}/immutable", "x", encoding="utf8") as f:
         assert not linux.ioctl_get_immutable(f.fileno())
 
 
@@ -37,7 +37,7 @@ def test_ioctl_toggle_immutable(tmpdir):
     # as intended.
     #
 
-    with open(f"{tmpdir}/immutable", "x") as f:
+    with open(f"{tmpdir}/immutable", "x", encoding="utf8") as f:
         # Check the file is mutable by default and if we clear it again.
         assert not linux.ioctl_get_immutable(f.fileno())
         linux.ioctl_toggle_immutable(f.fileno(), False)
diff --git a/test/mod/test_util_lorax.py b/test/mod/test_util_lorax.py
index ad1df2a2..dada02a7 100644
--- a/test/mod/test_util_lorax.py
+++ b/test/mod/test_util_lorax.py
@@ -42,13 +42,13 @@ class TestUtilLorax(test.TestBase):
             os.makedirs(root)
             os.makedirs(tree)
 
-            with open(os.path.join(root, "hello.txt"), "w") as f:
+            with open(os.path.join(root, "hello.txt"), "w", encoding="utf8") as f:
                 f.write("Hello World\n")
 
             self.assertExists(root, "hello.txt")
 
             template = os.path.join(tmp, "template.tmpl")
-            with open(os.path.join(tmp, template), "w") as f:
+            with open(os.path.join(tmp, template), "w", encoding="utf8") as f:
                 f.write(BASIC_TEMPLATE)
 
             # parse the template and render it
@@ -76,7 +76,7 @@ class TestUtilLorax(test.TestBase):
             self.assertExists(tree, "foo.txt")
 
             for fn in ["a.txt", "b.txt"]:
-                with open(os.path.join(tree, fn), "r") as f:
+                with open(os.path.join(tree, fn), "r", encoding="utf8") as f:
                     data = f.read().strip()
                     self.assertEqual(data, "osbuild-42")
 
diff --git a/test/mod/test_util_lvm2.py b/test/mod/test_util_lvm2.py
index 53a50923..0042e794 100644
--- a/test/mod/test_util_lvm2.py
+++ b/test/mod/test_util_lvm2.py
@@ -24,7 +24,7 @@ def have_lvm() -> bool:
     try:
         r = subprocess.run(
             ["vgs"],
-            encoding="utf-8",
+            encoding="utf8",
             stdout=subprocess.PIPE,
             check=False
         )
diff --git a/test/mod/test_util_ostree.py b/test/mod/test_util_ostree.py
index ad1ad427..cb5ffcff 100644
--- a/test/mod/test_util_ostree.py
+++ b/test/mod/test_util_ostree.py
@@ -15,7 +15,7 @@ from osbuild.util import ostree
 from .. import test
 
 
-def run(*args, check=True, encoding="utf-8", **kwargs):
+def run(*args, check=True, encoding="utf8", **kwargs):
     res = subprocess.run(*args,
                          encoding=encoding,
                          check=check,
@@ -56,7 +56,7 @@ class TestObjectStore(test.TestBase):
         tf["ref"] = test_ref
 
         with tf.as_tmp_file() as path:
-            with open(path, "r") as f:
+            with open(path, "r", encoding="utf8") as f:
                 js = json.load(f)
                 self.assertEqual(js["ref"], test_ref)
                 self.assertEqual(tf["ref"], test_ref)
@@ -118,16 +118,16 @@ class TestPasswdLike(unittest.TestCase):
                 "lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin\n",
                 "sync:x:5:0:sync:/sbin:/bin/sync\n"
             ]
-            with open(os.path.join(tmpdir, "primary"), "w") as f:
+            with open(os.path.join(tmpdir, "primary"), "w", encoding="utf8") as f:
                 f.writelines(primary_file_lines)
-            with open(os.path.join(tmpdir, "secondary"), "w") as f:
+            with open(os.path.join(tmpdir, "secondary"), "w", encoding="utf8") as f:
                 f.writelines(secondary_file_lines)
 
             passwd = ostree.PasswdLike.from_file(os.path.join(tmpdir, "primary"))
             passwd.merge_with_file(os.path.join(tmpdir, "secondary"))
             passwd.dump_to_file(os.path.join(tmpdir, "result"))
 
-            with open(os.path.join(tmpdir, "result"), "r") as f:
+            with open(os.path.join(tmpdir, "result"), "r", encoding="utf8") as f:
                 self.assertEqual(sorted(f.readlines()), sorted(result_file_lines))
 
     def test_merge_group(self):
@@ -145,16 +145,16 @@ class TestPasswdLike(unittest.TestCase):
                 "bin:x:1:\n",
                 "daemon:x:2:\n"
             ]
-            with open(os.path.join(tmpdir, "primary"), "w") as f:
+            with open(os.path.join(tmpdir, "primary"), "w", encoding="utf8") as f:
                 f.writelines(primary_file_lines)
-            with open(os.path.join(tmpdir, "secondary"), "w") as f:
+            with open(os.path.join(tmpdir, "secondary"), "w", encoding="utf8") as f:
                 f.writelines(secondary_file_lines)
 
             passwd = ostree.PasswdLike.from_file(os.path.join(tmpdir, "primary"))
             passwd.merge_with_file(os.path.join(tmpdir, "secondary"))
             passwd.dump_to_file(os.path.join(tmpdir, "result"))
 
-            with open(os.path.join(tmpdir, "result"), "r") as f:
+            with open(os.path.join(tmpdir, "result"), "r", encoding="utf8") as f:
                 self.assertEqual(sorted(f.readlines()), sorted(result_file_lines))
 
     #pylint: disable=no-self-use
diff --git a/test/run/test_assemblers.py b/test/run/test_assemblers.py
index 66935068..aafc2e46 100644
--- a/test/run/test_assemblers.py
+++ b/test/run/test_assemblers.py
@@ -29,7 +29,8 @@ class TestAssemblers(test.TestBase):
     @contextlib.contextmanager
     def run_assembler(self, osb, name, options, output_path):
         with open(os.path.join(self.locate_test_data(),
-                               "manifests/filesystem.json")) as f:
+                               "manifests/filesystem.json"),
+                               encoding="utf8") as f:
             manifest = json.load(f)
         manifest["pipeline"] = dict(
             manifest["pipeline"],
@@ -51,7 +52,7 @@ class TestAssemblers(test.TestBase):
         self.assertEqual(info["virtual-size"], expected_size)
 
     def assertFilesystem(self, device, uuid, fstype, tree):
-        output = subprocess.check_output(["blkid", "--output", "export", device], encoding="utf-8")
+        output = subprocess.check_output(["blkid", "--output", "export", device], encoding="utf8")
         blkid = dict(line.split("=") for line in output.strip().split("\n"))
         self.assertEqual(blkid["UUID"], uuid)
         self.assertEqual(blkid["TYPE"], fstype)
@@ -113,7 +114,8 @@ class TestAssemblers(test.TestBase):
     def test_ostree(self):
         with self.osbuild as osb:
             with open(os.path.join(self.locate_test_data(),
-                                   "manifests/fedora-ostree-commit.json")) as f:
+                                   "manifests/fedora-ostree-commit.json"),
+                                   encoding="utf8") as f:
                 manifest = json.load(f)
 
             data = json.dumps(manifest)
@@ -122,7 +124,7 @@ class TestAssemblers(test.TestBase):
                 compose_file = os.path.join(output_dir, "ostree-commit", "compose.json")
                 repo = os.path.join(output_dir, "ostree-commit", "repo")
 
-                with open(compose_file) as f:
+                with open(compose_file, encoding="utf8") as f:
                     compose = json.load(f)
                 commit_id = compose["ostree-commit"]
                 ref = compose["ref"]
@@ -146,7 +148,7 @@ class TestAssemblers(test.TestBase):
                         "--repo", repo,
                         "--print-metadata-key=rpmostree.inputhash",
                         commit_id
-                    ], encoding="utf-8").strip()
+                    ], encoding="utf8").strip()
                 self.assertEqual(md, f"'{rpmostree_inputhash}'")
 
                 md = subprocess.check_output(
@@ -156,7 +158,7 @@ class TestAssemblers(test.TestBase):
                         "--repo", repo,
                         "--print-metadata-key=version",
                         commit_id
-                    ], encoding="utf-8").strip()
+                    ], encoding="utf8").strip()
                 self.assertEqual(md, f"'{os_version}'")
 
     @unittest.skipUnless(test.TestBase.have_tree_diff(), "tree-diff missing")
@@ -223,7 +225,7 @@ class TestAssemblers(test.TestBase):
                                         "org.osbuild.tar",
                                         options,
                                         filename) as (tree, image):
-                    output = subprocess.check_output(["file", "--mime-type", image], encoding="utf-8")
+                    output = subprocess.check_output(["file", "--mime-type", image], encoding="utf8")
                     _, mimetype = output.strip().split(": ")  # "filename: mimetype"
                     self.assertIn(mimetype, expected_mimetypes)
 
@@ -240,7 +242,7 @@ class TestAssemblers(test.TestBase):
                             "--xattrs", "--xattrs-include", "*",
                             "-xaf", image,
                             "-C", tmp]
-                        subprocess.check_output(args, encoding="utf-8")
+                        subprocess.check_output(args, encoding="utf8")
                         diff = self.tree_diff(tree, tmp)
                         self.assertEqual(diff["added_files"], [])
                         self.assertEqual(diff["deleted_files"], [])
diff --git a/test/run/test_boot.py b/test/run/test_boot.py
index 5e0c0073..60962c4d 100644
--- a/test/run/test_boot.py
+++ b/test/run/test_boot.py
@@ -46,7 +46,7 @@ class TestBoot(test.TestBase):
                                 "-device", "virtserialport,chardev=stdio",
 
                                 qcow2],
-                               encoding="utf-8",
+                               encoding="utf8",
                                check=True)
-                with open(output_file, "r") as f:
+                with open(output_file, "r", encoding="utf8") as f:
                     self.assertEqual(f.read().strip(), "running")
diff --git a/test/run/test_devices.py b/test/run/test_devices.py
index 2293867b..ab67e521 100755
--- a/test/run/test_devices.py
+++ b/test/run/test_devices.py
@@ -77,5 +77,5 @@ def test_loopback_basic(tmpdir):
         client.call("close", None)
 
         lo = loop.Loop(minor)
-        with open(filename, "r") as f:
+        with open(filename, "r", encoding="utf8") as f:
             assert not lo.is_bound_to(f.fileno())
diff --git a/test/run/test_sources.py b/test/run/test_sources.py
index 8cdbcc14..4d14e8af 100644
--- a/test/run/test_sources.py
+++ b/test/run/test_sources.py
@@ -35,7 +35,7 @@ libc.setns.errcheck = errcheck
 @contextlib.contextmanager
 def netns():
     # Grab a reference to the current namespace.
-    with open("/proc/self/ns/net") as oldnet:
+    with open("/proc/self/ns/net", encoding="utf8") as oldnet:
         # Create a new namespace and enter it.
         libc.unshare(CLONE_NEWNET)
         try:
@@ -76,7 +76,7 @@ def runFileServer(barrier, directory):
 
         def guess_type(self, path):
             try:
-                with open(path + ".mimetype", "r") as f:
+                with open(path + ".mimetype", "r", encoding="utf8") as f:
                     return f.read().strip()
             except FileNotFoundError:
                 pass
@@ -119,7 +119,7 @@ def test_sources(source, case, tmpdir):
     index = osbuild.meta.Index(os.curdir)
     sources = os.path.join(test.TestBase.locate_test_data(), "sources")
 
-    with open(f"{sources}/{source}/cases/{case}") as f:
+    with open(f"{sources}/{source}/cases/{case}", encoding="utf8") as f:
         case_options = json.load(f)
 
     info = index.get_module_info("Source", source)
diff --git a/test/run/test_stages.py b/test/run/test_stages.py
index 3edcc41f..593e5916 100644
--- a/test/run/test_stages.py
+++ b/test/run/test_stages.py
@@ -25,7 +25,7 @@ def have_sfdisk_with_json():
     r = subprocess.run(["sfdisk", "--version"],
                        stdout=subprocess.PIPE,
                        stderr=subprocess.PIPE,
-                       encoding="utf-8",
+                       encoding="utf8",
                        check=False)
 
     if r.returncode != 0:
@@ -187,7 +187,7 @@ class TestStages(test.TestBase):
                                      pprint.pformat(want).splitlines())
                 txt = "\n".join(diff)
                 path = f"/tmp/osbuild.metadata.{stageid}.json"
-                with open(path, "w") as f:
+                with open(path, "w", encoding="utf8") as f:
                     json.dump(have, f, indent=2)
                 self.fail(f"metadata for {stageid} differs:\n{txt}\n{path}")
 
@@ -224,14 +224,14 @@ class TestStages(test.TestBase):
 
             actual_diff = self.tree_diff(tree1, tree2)
 
-            with open(os.path.join(test_dir, "diff.json")) as f:
+            with open(os.path.join(test_dir, "diff.json"), encoding="utf8") as f:
                 expected_diff = json.load(f)
 
             self.assertTreeDiffsEqual(expected_diff, actual_diff)
 
             md_path = os.path.join(test_dir, "metadata.json")
             if os.path.exists(md_path):
-                with open(md_path, "r") as f:
+                with open(md_path, "r", encoding="utf8") as f:
                     metadata = json.load(f)
 
                 self.assertMetadata(metadata, res)
@@ -245,7 +245,7 @@ class TestStages(test.TestBase):
         datadir = self.locate_test_data()
         base = os.path.join(datadir, "stages/dracut")
 
-        with open(f"{base}/vanilla.json", "r") as f:
+        with open(f"{base}/vanilla.json", "r", encoding="utf8") as f:
             refs = json.load(f)
 
         with self.osbuild as osb, tempfile.TemporaryDirectory(dir="/var/tmp") as outdir:
@@ -273,7 +273,7 @@ class TestStages(test.TestBase):
         testdir = os.path.join(datadir, "stages", "selinux")
 
         def load_manifest(manifest_name):
-            with open(os.path.join(datadir, f"manifests/{manifest_name}")) as f:
+            with open(os.path.join(datadir, f"manifests/{manifest_name}"), encoding="utf8") as f:
                 manifest = json.load(f)
                 return manifest
 
@@ -281,7 +281,7 @@ class TestStages(test.TestBase):
 
             for t in glob.glob(f"{testdir}/test_*.json"):
                 manifest = load_manifest("f34-base.json")
-                with open(t) as f:
+                with open(t, encoding="utf8") as f:
                     check = json.load(f)
                 manifest["pipeline"]["stages"].append({
                     "name": "org.osbuild.selinux",
@@ -308,7 +308,7 @@ class TestStages(test.TestBase):
 
         checks_path = os.path.join(testdir, "checks.json")
         checks = {}
-        with open(checks_path) as f:
+        with open(checks_path, encoding="utf8") as f:
             checks = json.load(f)
 
         for image_name, test_data in checks.items():
@@ -326,7 +326,7 @@ class TestStages(test.TestBase):
                     ["qemu-img", "info", "--output=json", ip],
                     capture_output=True,
                     check=True,
-                    encoding="utf-8"
+                    encoding="utf8"
                 )
 
                 qemu_img_out = json.loads(qemu_img_run.stdout)
@@ -371,7 +371,7 @@ class TestStages(test.TestBase):
 
         imgname = "disk.img"
 
-        with open(os.path.join(testdir, f"{imgname}.json"), "r") as f:
+        with open(os.path.join(testdir, f"{imgname}.json"), "r", encoding="utf8") as f:
             want = json.load(f)
 
         with self.osbuild as osb, tempfile.TemporaryDirectory(dir="/var/tmp") as outdir:
@@ -388,7 +388,7 @@ class TestStages(test.TestBase):
             r = subprocess.run(["sfdisk", "--json", target],
                                stdout=subprocess.PIPE,
                                stderr=subprocess.PIPE,
-                               encoding="utf-8",
+                               encoding="utf8",
                                check=False)
 
             have = json.loads(r.stdout)
@@ -419,7 +419,7 @@ class TestStages(test.TestBase):
 
         imgname = "disk.img"
 
-        with open(os.path.join(testdir, f"{imgname}.json"), "r") as f:
+        with open(os.path.join(testdir, f"{imgname}.json"), "r", encoding="utf8") as f:
             want = json.load(f)
 
         with self.osbuild as osb, tempfile.TemporaryDirectory(dir="/var/tmp") as outdir:
@@ -436,7 +436,7 @@ class TestStages(test.TestBase):
             r = subprocess.run(["sfdisk", "--json", target],
                                stdout=subprocess.PIPE,
                                stderr=subprocess.PIPE,
-                               encoding="utf-8",
+                               encoding="utf8",
                                check=False)
 
             have = json.loads(r.stdout)
diff --git a/test/test.py b/test/test.py
index d4cdd8c7..366c4666 100644
--- a/test/test.py
+++ b/test/test.py
@@ -133,9 +133,9 @@ class TestBase(unittest.TestCase):
             original = os.path.join(tmpdir, "original")
             mnt = os.path.join(tmpdir, "mnt")
 
-            with open(original, "w") as f:
+            with open(original, "w", encoding="utf8") as f:
                 f.write("foo")
-            with open(mnt, "w") as f:
+            with open(mnt, "w", encoding="utf8") as f:
                 f.write("bar")
 
             try:
@@ -153,7 +153,7 @@ class TestBase(unittest.TestCase):
                     stderr=subprocess.DEVNULL,
                     check=True,
                 )
-                with open(mnt, "r") as f:
+                with open(mnt, "r", encoding="utf8") as f:
                     assert f.read() == "foo"
                 return True
             except subprocess.CalledProcessError:
@@ -178,7 +178,7 @@ class TestBase(unittest.TestCase):
         try:
             r = subprocess.run(
                 ["autopep8-3", "--version"],
-                encoding="utf-8", stdout=subprocess.PIPE, check=False
+                encoding="utf8", stdout=subprocess.PIPE, check=False
             )
         except FileNotFoundError:
             return False
@@ -196,7 +196,7 @@ class TestBase(unittest.TestCase):
         try:
             r = subprocess.run(
                 ["rpm-ostree", "--version"],
-                encoding="utf-8", stdout=subprocess.PIPE, check=False
+                encoding="utf8", stdout=subprocess.PIPE, check=False
             )
         except FileNotFoundError:
             return False
@@ -333,7 +333,7 @@ class OSBuild(contextlib.AbstractContextManager):
 
             cmd_args += ["-"]
 
-            logfile_context = tempfile.NamedTemporaryFile(dir="/var/tmp", mode="w+", encoding="utf-8")
+            logfile_context = tempfile.NamedTemporaryFile(dir="/var/tmp", mode="w+", encoding="utf8")
             logfile = cm.enter_context(logfile_context)
 
             cmd_args += ["--monitor", "LogMonitor", "--monitor-fd", str(logfile.fileno())]
@@ -345,7 +345,7 @@ class OSBuild(contextlib.AbstractContextManager):
             try:
                 p = subprocess.Popen(
                     cmd_args,
-                    encoding="utf-8",
+                    encoding="utf8",
                     stdin=subprocess.PIPE,
                     stdout=subprocess.PIPE,
                     stderr=subprocess.PIPE,
@@ -376,7 +376,7 @@ class OSBuild(contextlib.AbstractContextManager):
         to `compile()`.
         """
 
-        with open(file_stdin, "r") as f:
+        with open(file_stdin, "r", encoding="utf8") as f:
             data_stdin = f.read()
             return self.compile(data_stdin, output_dir, checkpoints=checkpoints, exports=exports)