Audit existing unit test coverage for all components about ztunnel

[stevenctl]

We should have some reasonable code coverage
target (~60%). This is a bad metric, but it’s a starting point to identifying where to test. This isn’t a long-term standard we will measure, it’s just getting us coverage on the initial impl.

TODO - call out specific components/scenarios that we should test.

[SkyfireFrancisZ]

@stevenctl will create a list of tests needed.

[stevenctl]

Expect several issues to be created today, as well PR(s)

[stevenctl]

                          Module  Statements   Missing  Excluded  Branches   Partial    Coverage
                src/xds/client.rs         453       265                   0         0         42%
                      src/main.rs          63        31                   0         0         51%
             src/identity/auth.rs          62        28                   0         0         55%
         src/identity/caclient.rs          94        35                   0         0         63%
          src/test_helpers/tcp.rs         124        46                   0         0         63%
          src/test_helpers/mod.rs          33        12                   0         0         64%
                   src/version.rs          51        14                   0         0         73%
 src/proxy/inbound_passthrough.rs          69        18                   0         0         74%
                    src/socket.rs         196        44                   0         0         78%
                 src/admin/mod.rs         346        74                   0         0         79%
            src/proxy/outbound.rs         581        97                   0         0         83%
                src/tls/boring.rs         495        81                   0         0         84%
                 src/proxy/mod.rs         199        32                   0         0         84%
             src/proxy/inbound.rs         212        29                   0         0         86%
              src/proxy/socks5.rs         193        20                   0         0         90%
                  src/workload.rs         741        64                   0         0         91%
          src/identity/manager.rs         375        30                   0         0         92%
                    src/signal.rs          86         5                   0         0         94%
                       src/app.rs         112         6                   0         0         95%
                    src/config.rs          94         5                   0         0         95%
                   src/tls/mod.rs          21         1                   0         0         95%
                   src/xds/mod.rs          23         1                   0         0         96%
          src/test_helpers/app.rs         127         5                   0         0         96%
              src/identity/mod.rs          26         1                   0         0         96%
      src/test_helpers/helpers.rs          28         0                   0         0        100%
                       src/lib.rs           1         0                   0         0        100%
                   tests/proxy.rs         111         0                   0         0        100%
                 src/telemetry.rs          46         0                   0         0        100%
                            Total        4962       944                   0         0         81%

[stevenctl]

I think the statement/missing counts are off because it's after macro expansion