Also support --python= arg format

Signed-off-by: Bernat Gabor <bgabor8@bloomberg.net>

pipdeptree.py

@@ -791,9 +791,12 @@ def handle_non_host_target(args):
                   " non-host python", file=sys.stderr)
             raise SystemExit(1)
         argv = sys.argv[1:]  # remove current python executable
-        py_at = argv.index('--python')  # plus the new python target
-        del argv[py_at]
-        del argv[py_at]
+        for py_at, value in enumerate(argv):
+            if value == "--python":
+                del argv[py_at]
+                del argv[py_at]
+            elif value.startswith("--python"):
+                del argv[py_at]
         # feed the file as argument, instead of file
         # to avoid adding the file path to sys.path, that can affect result
         file_path = inspect.getsourcefile(sys.modules[__name__])

tests/test_pipdeptree.py

@@ -523,9 +523,11 @@ def test_parser_svg():
     assert not args.json
 
 
-def test_custom_interpreter(tmp_path, monkeypatch, capfd):
+@pytest.mark.parametrize('args_joined', [True, False])
+def test_custom_interpreter(tmp_path, monkeypatch, capfd, args_joined):
     result = virtualenv.cli_run([str(tmp_path), '--activators', ''])
-    cmd = [sys.executable, '--python', str(result.creator.exe)]
+    cmd = [sys.executable]
+    cmd += ['--python={}'.format(result.creator.exe)] if args_joined else ['--python', str(result.creator.exe)]
     monkeypatch.setattr(sys, 'argv', cmd)
     p.main()
     out, _ = capfd.readouterr()