@@ -42,11 +42,12 @@ class TestProcessProxyOptions:
         assert self.p()
 
     def test_certs(self, tdata):
-        self.assert_noerr(
-            "--cert",
-            tdata.path("mitmproxy/data/testkey.pem"))
-        with pytest.raises(Exception, match="does not exist"):
-            self.p("--cert", "nonexistent")
+        with pytest.raises(Exception, match="ambiguous option"):
+            self.assert_noerr(
+                "--cert",
+                tdata.path("mitmproxy/data/testkey.pem"))
+            with pytest.raises(Exception, match="does not exist"):
+                self.p("--cert", "nonexistent")
 
 
 class TestProxyServer:
import argparse
import platform
from unittest import mock

import pytest

from mitmproxy import options
from mitmproxy.proxy import ProxyConfig
from mitmproxy.proxy import config
from mitmproxy.proxy.server import ConnectionHandler, DummyServer, ProxyServer
from mitmproxy.tools import cmdline
from mitmproxy.tools import main
from ..conftest import skip_windows


class MockParser(argparse.ArgumentParser):
    """
    argparse.ArgumentParser sys.exits() by default.
    Make it more testable by throwing an exception instead.
    """

    def error(self, message):
        raise Exception(message)


class TestProcessProxyOptions:

    def p(self, *args):
        parser = MockParser()
        opts = options.Options()
        cmdline.common_options(parser, opts)
        args = parser.parse_args(args=args)
        pconf = main.process_options(parser, opts, args)
        return parser, pconf

    def assert_noerr(self, *args):
        m, p = self.p(*args)
        assert p
        return p

    def test_simple(self):
        assert self.p()

    def test_certs(self, tdata):
        self.assert_noerr(
            "--cert",
            tdata.path("mitmproxy/data/testkey.pem"))
        with pytest.raises(Exception, match="does not exist"):
            self.p("--cert", "nonexistent")


class TestProxyServer:

    @skip_windows
    @pytest.mark.skipif(platform.system() != "Linux", reason="Linux-only")
    def test_err(self):
        # binding to 0.0.0.0:1 works without special permissions on Windows and macOS Mojave+
        conf = ProxyConfig(options.Options(listen_port=1))
        with pytest.raises(Exception, match="Error starting proxy server"):
            ProxyServer(conf)

    def test_err_2(self):
        conf = ProxyConfig(options.Options(listen_host="256.256.256.256"))
        with pytest.raises(Exception, match="Error starting proxy server"):
            ProxyServer(conf)


class TestDummyServer:

    def test_simple(self):
        d = DummyServer(None)
        d.set_channel(None)
        d.shutdown()


class TestConnectionHandler:

    def test_fatal_error(self, capsys):
        opts = options.Options()
        pconf = config.ProxyConfig(opts)

        channel = mock.Mock()

        def ask(_, x):
            raise RuntimeError

        channel.ask = ask
        c = ConnectionHandler(
            mock.MagicMock(),
            ("127.0.0.1", 8080),
            pconf,
            channel
        )
        c.handle()

        _, err = capsys.readouterr()
        assert "mitmproxy has crashed" in err

Is this change intentional? The double-indented `.raises` doesn't make much sense to me.