gh-127637: add tests for dis command-line interface (#127759)

Author: picnixz

Lib/dis.py

@@ -790,12 +790,12 @@ def dis(self):
             return output.getvalue()
 
 
-def main():
+def main(args=None):
     import argparse
 
     parser = argparse.ArgumentParser()
     parser.add_argument('infile', type=argparse.FileType('rb'), nargs='?', default='-')
-    args = parser.parse_args()
+    args = parser.parse_args(args=args)
     with args.infile as infile:
         source = infile.read()
     code = compile(source, args.infile.name, "exec")

Lib/test/test_dis.py

@@ -5,10 +5,12 @@
 import io
 import re
 import sys
+import tempfile
 import types
 import unittest
 from test.support import (captured_stdout, requires_debug_ranges,
-                          requires_specialization, cpython_only)
+                          requires_specialization, cpython_only,
+                          os_helper)
 from test.support.bytecode_helper import BytecodeTestCase
 
 import opcode
@@ -2069,5 +2071,18 @@ def get_disassembly(self, tb):
         return output.getvalue()
 
 
+class TestDisCLI(unittest.TestCase):
+
+    def setUp(self):
+        self.filename = tempfile.mktemp()
+        self.addCleanup(os_helper.unlink, self.filename)
+
+    def test_invocation(self):
+        with self.assertRaises(SystemExit):
+            # suppress argparse error message
+            with contextlib.redirect_stderr(io.StringIO()):
+                dis.main(args=['--unknown', self.filename])
+
+
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Tests/2024-12-09-12-35-44.gh-issue-127637.KLx-9I.rst

@@ -0,0 +1 @@
+Add tests for the :mod:`dis` command-line interface. Patch by Bénédikt Tran.