lnd.xprv/channeldb/migration_01_to_11/channel_cache_test.go
Joost Jager 6e463c1634
channeldb: make copy for migrations
This commit is a direct copy of the complete channeldb package. It only
changes the package declaration at the top of every file. We make this
full copy so that review can be focused on the actual changes made.
Otherwise changes may drown in all the file moves.

Linting for the new package is disabled, as it contains lots of
pre-existing issues.
2019-10-24 12:49:38 +02:00

106 lines
3.0 KiB
Go

package migration_01_to_11
import (
"reflect"
"testing"
)
// TestChannelCache checks the behavior of the channelCache with respect to
// insertion, eviction, and removal of cache entries.
func TestChannelCache(t *testing.T) {
const cacheSize = 100
// Create a new channel cache with the configured max size.
c := newChannelCache(cacheSize)
// As a sanity check, assert that querying the empty cache does not
// return an entry.
_, ok := c.get(0)
if ok {
t.Fatalf("channel cache should be empty")
}
// Now, fill up the cache entirely.
for i := uint64(0); i < cacheSize; i++ {
c.insert(i, channelForInt(i))
}
// Assert that the cache has all of the entries just inserted, since no
// eviction should occur until we try to surpass the max size.
assertHasChanEntries(t, c, 0, cacheSize)
// Now, insert a new element that causes the cache to evict an element.
c.insert(cacheSize, channelForInt(cacheSize))
// Assert that the cache has this last entry, as the cache should evict
// some prior element and not the newly inserted one.
assertHasChanEntries(t, c, cacheSize, cacheSize)
// Iterate over all inserted elements and construct a set of the evicted
// elements.
evicted := make(map[uint64]struct{})
for i := uint64(0); i < cacheSize+1; i++ {
_, ok := c.get(i)
if !ok {
evicted[i] = struct{}{}
}
}
// Assert that exactly one element has been evicted.
numEvicted := len(evicted)
if numEvicted != 1 {
t.Fatalf("expected one evicted entry, got: %d", numEvicted)
}
// Remove the highest item which initially caused the eviction and
// reinsert the element that was evicted prior.
c.remove(cacheSize)
for i := range evicted {
c.insert(i, channelForInt(i))
}
// Since the removal created an extra slot, the last insertion should
// not have caused an eviction and the entries for all channels in the
// original set that filled the cache should be present.
assertHasChanEntries(t, c, 0, cacheSize)
// Finally, reinsert the existing set back into the cache and test that
// the cache still has all the entries. If the randomized eviction were
// happening on inserts for existing cache items, we expect this to fail
// with high probability.
for i := uint64(0); i < cacheSize; i++ {
c.insert(i, channelForInt(i))
}
assertHasChanEntries(t, c, 0, cacheSize)
}
// assertHasEntries queries the edge cache for all channels in the range [start,
// end), asserting that they exist and their value matches the entry produced by
// entryForInt.
func assertHasChanEntries(t *testing.T, c *channelCache, start, end uint64) {
t.Helper()
for i := start; i < end; i++ {
entry, ok := c.get(i)
if !ok {
t.Fatalf("channel cache should contain chan %d", i)
}
expEntry := channelForInt(i)
if !reflect.DeepEqual(entry, expEntry) {
t.Fatalf("entry mismatch, want: %v, got: %v",
expEntry, entry)
}
}
}
// channelForInt generates a unique ChannelEdge given an integer.
func channelForInt(i uint64) ChannelEdge {
return ChannelEdge{
Info: &ChannelEdgeInfo{
ChannelID: i,
},
}
}