test for --version argument

tests/test_main.py

@@ -5,6 +5,7 @@
 from hypothesis_auto import auto_pytest_magic
 
 from isort import main
+from isort._version import __version__
 from isort.settings import DEFAULT_CONFIG
 
 auto_pytest_magic(main.sort_imports)
@@ -25,6 +26,27 @@ def test_is_python_file():
     assert not main.is_python_file("file.pex")
 
 
+def test_ascii_art(capsys):
+    main.main(["--version"])
+    out, error = capsys.readouterr()
+    assert (
+        out
+        == f"""
+                 _                 _
+                (_) ___  ___  _ __| |_
+                | |/ _/ / _ \\/ '__  _/
+                | |\\__ \\/\\_\\/| |  | |_
+                |_|\\___/\\___/\\_/   \\_/
+
+      isort your imports, so you don't have to.
+
+                    VERSION {__version__}
+
+"""
+    )
+    assert error == ""
+
+
 @pytest.mark.skipif(sys.platform == "win32", reason="cannot create fifo file on Windows platform")
 def test_is_python_file_fifo(tmpdir):
     fifo_file = os.path.join(tmpdir, "fifo_file")