diff --git a/stages/test/test_mkfs_ext4.py b/stages/test/test_mkfs_ext4.py
new file mode 100644
index 00000000..0c0ea2f0
--- /dev/null
+++ b/stages/test/test_mkfs_ext4.py
@@ -0,0 +1,110 @@
+#!/usr/bin/python3
+
+import os.path
+import re
+import subprocess
+from unittest import mock
+
+import pytest
+
+import osbuild.meta
+from osbuild.testutil import has_executable
+from osbuild.testutil.imports import import_module_from_path
+
+
+@pytest.mark.parametrize("test_data,expected_err", [
+    # bad
+    ({}, "'uuid' is a required property"),
+    ({"uuid": 123}, "123 is not of type 'string'"),
+    ({"uuid": "vaild", "label": "12345678901234567"}, " is too long"),
+    ({"uuid": "valid", "verity": "please"}, "'please' is not of type 'boolean'"),
+    # good
+    ({"uuid": "some", "label": "1234567890123456"}, ""),
+    ({"uuid": "some", "label": "label", "verity": True}, ""),
+    # actually "some-uuid" will not be accepted by mkfs, it has to be a valid
+    # uuid but our schema is not strict enough right now
+    ({"uuid": "some-uuid"}, ""),
+])
+def test_schema_validation_mkfs_ext4(test_data, expected_err):
+    name = "org.osbuild.mkfs.ext4"
+    root = os.path.join(os.path.dirname(__file__), "../..")
+    mod_info = osbuild.meta.ModuleInfo.load(root, "Stage", name)
+    schema = osbuild.meta.Schema(mod_info.get_schema(version="2"), name)
+
+    test_input = {
+        "type": "org.osbuild.mkfs.ext4",
+        "devices": {
+            "device": {
+                "path": "some-path",
+            },
+        },
+        "options": {
+        }
+    }
+    test_input["options"].update(test_data)
+    res = schema.validate(test_input)
+
+    if expected_err == "":
+        assert res.valid is True, f"err: {[e.as_dict() for e in res.errors]}"
+    else:
+        assert res.valid is False
+        assert len(res.errors) == 1, [e.as_dict() for e in res.errors]
+        err_msgs = [e.as_dict()["message"] for e in res.errors]
+        assert expected_err in err_msgs[0]
+
+
+@pytest.mark.skipif(not has_executable("mkfs.ext4"), reason="need mkfs.ext4")
+def test_mkfs_ext4_integration(tmp_path):
+    stage_path = os.path.join(os.path.dirname(__file__), "../org.osbuild.mkfs.ext4")
+    stage = import_module_from_path("mkfs_ext4_stage", stage_path)
+
+    fake_disk_path = tmp_path / "fake.img"
+    with fake_disk_path.open("w"):
+        os.truncate(os.fspath(fake_disk_path), 10 * 1024 * 1024)
+    devices = {
+        "device": {
+            "path": fake_disk_path,
+        },
+    }
+    fake_uuid = "a957573a-f432-4bed-a0bc-e541bddf8579"
+    options = {
+        "uuid": fake_uuid,
+    }
+    stage.main(devices, options)
+    assert os.path.exists(fake_disk_path)
+    output = subprocess.check_output([
+        "dumpe2fs", fake_disk_path], encoding="utf-8")
+    assert re.search(f"(?ms)Filesystem UUID:\\ +{fake_uuid}", output), \
+        f"expected uuid not found in {output}"
+
+
+@pytest.mark.parametrize("test_input,expected", [
+    ({}, []),
+    ({"verity": True}, ["-O", "verity"]),
+    ({"verity": False}, ["-O", "^verity"]),
+])
+@mock.patch("subprocess.run")
+def test_mkfs_ext4_cmdline(mock_run, test_input, expected):
+    stage_path = os.path.join(os.path.dirname(__file__), "../org.osbuild.mkfs.ext4")
+    stage = import_module_from_path("mkfs_ext4_stage", stage_path)
+
+    fake_disk_path = "/dev/xxd1"
+    devices = {
+        "device": {
+            "path": fake_disk_path,
+        },
+    }
+    fake_uuid = "a957573a-f432-4bed-a0bc-e541bddf8579"
+    options = {
+        "uuid": fake_uuid,
+    }
+    options.update(test_input)
+    stage.main(devices, options)
+
+    expected = [
+        "mkfs.ext4",
+        "-U", fake_uuid,
+    ] + expected + [
+        fake_disk_path,
+    ]
+    mock_run.assert_called_with(expected, encoding="utf8", check=True)