In this commit, we thread through the necessary state to allow users to
set a max shard amount. If this value is set, then this'll effectively
serve as a ceiling for all our split attempts. If we need to split,
we'll first try to use `paymentAmt/2`, if that's bigger than
`MaxShardAmt, then we'll use the latter instead.
Ideally in the future we have a dynamic way to automatically set both
the `MaxShardAmt` as well as `MaxParts` for users. Until then exposing
these two new fields will allow us to experiment with setting them
automatically using the RPC interface, and also give users a bit more
control over how we attempt to route payments, akin to coin control for
on-chain payments.
Fixes#4730
In this commit, we modify our build tag set up to allow the main test
files to be buildable w/o the current rpctest tag. We do this so that
those of us that use extensions which will compile live files like
vim-go can once again fix compile errors as we go in our editors.
In order to do this, we now make an external `testsCases` variable, and
have two variants: one that's empty (no build tag), and one that's fully
populated with all our tests (build tag active). As a result, the main
file will now always build regardless of if the build tag is active or
not, but we'll only actually execute tests if the `testCases` variable
has been populated.
As sample run w/ the tag off:
```
=== RUN TestLightningNetworkDaemon
--- PASS: TestLightningNetworkDaemon (0.00s)
PASS
ok github.com/lightningnetwork/lnd/lntest/itest 0.051s
```
To fix the compiler of some IDEs complaining about types and functions
it cannot find, we rename all files that contain tests back to lnd_xxx_test.go to make
sure they are compiled correctly.
