We have a "deadcode" bitmapsEqual which is actually used in testing but
probably shouldn't be, and we don't have a good container equality test.
Problem is, equality tests are sort of slow in the things-are-equal case,
which is the most common case, so we've got some moderately-specialized
code here; specifically, special comparison code that takes advantage
of knowing that if two containers have the same number of bits, you only
have to check whether all the bits from one are present in the other,
because that can't be true for differing containers with the same number
of bits. This reduces the runtime for the ContainerCombinations case
from about 24 seconds to a bit under 2 on my laptop, or from around
10 minutes to about 37 seconds with the race detector on.
Also simplify the InPlaceWrapper functions not to invoke bitmaps, because
it's not really necessary.
BtreeSeek is O(N^2) on its N, and there's not a ton of extra utility
to testing a larger range of values, so we reduce N by a bit, cutting
runtime from ~10s to <1s on my laptop. Also reduce the scale of the
BtreeDelete1/BtreeDelete2 tests a bit because, again, lots of runtime
for little marginal information.
This is pretty expensive even for default shard width, and very expensive
for ShardWidth = 1<<22, and we don't really get much extra benefit from
having a million values instead of a hundred or so.
The generation of slices from things, and use of reflect.DeepEqual to compare
the slices, is a lot more expensive than it needs to be. Omitting it removes most
of the runtime of the marshal tests.
The failure mode in question was pretty predictable and tied to number of
snapshots, not to number of bits written, so we can probably use a lot fewer
bits and still get good results, but this is really slow under -race testing.
There's no reason to have 10-20 seconds of delays for testing this,
because in testing, we're running things on the local machine and don't
need to worry about significant network lag. Make retry count and delay
settable options, and set them lower. Moves the Replica2 test in
server/server_test.go from ~21s to ~2s.
The random-value tests can be pathological, and in particular, the
test of arbitrarily-spaced values is in effect O(N^2), and with race
testing on, that test *alone* can take ten minutes to run, but
it's not really all that exciting. We just reduce a bunch of values
and/or test fewer things for these, which doesn't significantly alter
coverage, but reduces test runtime on my laptop with `-race` from
21 minutes to a bit under 5.
