Tests: Add host to ENV{no_proxy} when DNS lookup failure is expected
DNS lookup of an invalid host name fails with a different error in a proxy
environment than it does in an environment without proxy. Many tools,
including curl, use the no_proxy
environment variable to provid a list
of hosts for which proxy should not be used.
To make lookup failure consistent, add invalid host names to the
no_proxy
environment variable in tests that attempt to look up invalid
host names. This way the lookup will fail consistently regardless of
whether proxy is generally used or not.
It is also possible to make the tests work by the person (or automated process) running ctest
setting the no_proxy
environment variable. However, setting the environment variable is an extra step that make the tests less self-contained.