nixos/tests/dex-oidc: fix build (#340042)

  testScript = ''

    with subtest("Web server gets ready"):

        machine.wait_for_unit("dex.service")

        machine.wait_for_unit("dex.service", timeout=120)

        # Wait until server accepts connections

        machine.wait_until_succeeds("curl -fs 'localhost:8080/dex/auth/mock?client_id=oidcclient&response_type=code&redirect_uri=https://example.com/callback&scope=openid'")

        machine.wait_until_succeeds("curl -fs 'localhost:8080/dex/auth/mock?client_id=oidcclient&response_type=code&redirect_uri=https://example.com/callback&scope=openid'", timeout=120)

    with subtest("Login"):

        state = machine.succeed("curl -fs 'localhost:8080/dex/auth/mock?client_id=oidcclient&response_type=code&redirect_uri=https://example.com/callback&scope=openid' | sed -n 's/.*state=\\(.*\\)\">.*/\\1/p'").strip()

        print(f"Got state {state}")

        machine.succeed(f"curl -fs 'localhost:8080/dex/auth/mock/login?back=&state={state}' -d 'login=admin&password=password'")

        code = machine.succeed(f"curl -fs localhost:8080/dex/approval?req={state} | sed -n 's/.*code=\\(.*\\)&.*/\\1/p'").strip()

        # Login request returns 303 with redirect_url that has code as query parameter:

        # https://example.com/callback?code=kibsamwdupuy2iwqnlbqei3u6&state=

        code = machine.succeed(f"curl -fs 'localhost:8080/dex/auth/mock/login?back=&state={state}' -d 'login=admin&password=password' -w '%{{redirect_url}}' | sed -n 's/.*code=\\(.*\\)&.*/\\1/p'")

        print(f"Got approval code {code}")

        bearer = machine.succeed(f"curl -fs localhost:8080/dex/token -u oidcclient:oidcclientsecret -d 'grant_type=authorization_code&redirect_uri=https://example.com/callback&code={code}' | jq .access_token -r").strip()

        print(f"Got access token {bearer}")