diff --git a/osism/main.py b/osism/main.py
index 82d26c23..ed072eb5 100644
--- a/osism/main.py
+++ b/osism/main.py
@@ -34,5 +34,5 @@ def main(argv=sys.argv[1:]):
     return result
 
 
-if __name__ == "__main__":
+if __name__ == "__main__":  # pragma: no cover
     sys.exit(main(sys.argv[1:]))
diff --git a/tests/unit/test_main.py b/tests/unit/test_main.py
new file mode 100644
index 00000000..cb62c681
--- /dev/null
+++ b/tests/unit/test_main.py
@@ -0,0 +1,127 @@
+# SPDX-License-Identifier: Apache-2.0
+
+"""Tests for ``osism/main.py`` — the ``osism`` console-script entry point.
+
+Two units are covered:
+
+- ``OsismApp.__init__`` wires loguru's stderr sink and the cliff ``App`` (the
+  ``osism.commands`` entry-point namespace, deferred help, parser description,
+  and the ``--version`` action). Every test that constructs ``OsismApp``
+  requests the ``mock_logger`` fixture so the process-global loguru
+  configuration is patched *before* construction and never mutated for real.
+- ``main`` constructs the app once, forwards ``argv`` unchanged, and returns
+  the app's exit code.
+
+``main``'s ``argv=sys.argv[1:]`` default is evaluated once at import time, so
+the default is frozen and reflects the arguments pytest itself was invoked
+with. Every test therefore passes ``argv`` explicitly. The ``main`` tests run
+only against a mocked ``OsismApp``; the real ``app.run([])`` is never called,
+as cliff would drop into its interactive shell on an empty argv.
+"""
+
+import sys
+
+import pytest
+
+from osism.main import OsismApp, main, __version__
+
+
+@pytest.fixture
+def mock_logger(mocker):
+    """Patch the loguru ``logger`` imported by ``osism.main``.
+
+    Returns the mock so tests can assert the sink configuration without
+    removing the loguru handlers other tests rely on.
+    """
+    return mocker.patch("osism.main.logger")
+
+
+# ---------------------------------------------------------------------------
+# OsismApp.__init__ — logging setup
+# ---------------------------------------------------------------------------
+
+
+def test_init_removes_default_loguru_handler(mock_logger):
+    OsismApp()
+    mock_logger.remove.assert_called_once_with()
+
+
+def test_init_adds_stderr_sink_with_expected_config(mock_logger):
+    OsismApp()
+
+    mock_logger.add.assert_called_once()
+    call_args = mock_logger.add.call_args
+    assert call_args.args[0] is sys.stderr
+    assert call_args.kwargs["level"] == "INFO"
+    assert call_args.kwargs["colorize"] is True
+    assert call_args.kwargs["format"].startswith(
+        "<green>{time:YYYY-MM-DD HH:mm:ss}</green>"
+    )
+
+
+# ---------------------------------------------------------------------------
+# OsismApp.__init__ — cliff wiring
+# ---------------------------------------------------------------------------
+
+
+def test_init_wires_osism_commands_namespace(mock_logger):
+    assert OsismApp().command_manager.namespace == "osism.commands"
+
+
+def test_init_enables_deferred_help(mock_logger):
+    assert OsismApp().deferred_help is True
+
+
+def test_init_sets_parser_description(mock_logger):
+    assert OsismApp().parser.description == "OSISM manager interface"
+
+
+def test_init_succeeds_when_version_is_none(mock_logger, mocker):
+    # osism.__version__ (pbr) is None when package metadata is unavailable
+    # (osism/__init__.py fallback); construction must still succeed.
+    mocker.patch("osism.main.__version__", None)
+    assert isinstance(OsismApp(), OsismApp)
+
+
+def test_version_option_exits_zero(mock_logger, capsys):
+    app = OsismApp()
+    with pytest.raises(SystemExit) as excinfo:
+        app.run(["--version"])
+    assert excinfo.value.code == 0
+    # cliff renders the version line as "<prog> <version>"; the prog name comes
+    # from sys.argv[0] (so it is "pytest" here, "osism" only via the console
+    # script). Assert on the package version that main.py wires in, which is
+    # what this entry point actually controls.
+    assert str(__version__) in capsys.readouterr().out
+
+
+# ---------------------------------------------------------------------------
+# main — construct once, forward argv, return the app's exit code
+# ---------------------------------------------------------------------------
+
+
+def test_main_constructs_app_once_and_forwards_argv(mocker):
+    mock_app_cls = mocker.patch("osism.main.OsismApp")
+
+    main(["reconciler", "sync"])
+
+    mock_app_cls.assert_called_once_with()
+    mock_app_cls.return_value.run.assert_called_once_with(["reconciler", "sync"])
+
+
+@pytest.mark.parametrize("rc", [42, 0])
+def test_main_returns_app_run_result(mocker, rc):
+    mock_app_cls = mocker.patch("osism.main.OsismApp")
+    mock_app_cls.return_value.run.return_value = rc
+
+    assert main(["reconciler", "sync"]) == rc
+
+
+def test_main_forwards_empty_argv(mocker):
+    # Only the mocked app sees the empty argv — never the real OsismApp, which
+    # would enter cliff's interactive shell on an empty argument list.
+    mock_app_cls = mocker.patch("osism.main.OsismApp")
+
+    main([])
+
+    mock_app_cls.return_value.run.assert_called_once_with([])