session: ensure listed sessions are sorted

Sorted by creation time. Also add a test to cover this.

Author: ellemouton

session/kvdb_store.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"sort"
 	"time"
 
 	"github.com/btcsuite/btcd/btcec/v2"
@@ -367,6 +368,14 @@ func (db *BoltStore) GetSession(key *btcec.PublicKey) (*Session, error) {
 //
 // NOTE: this is part of the Store interface.
 func (db *BoltStore) ListSessions(filterFn func(s *Session) bool) ([]*Session, error) {
+	return db.listSessions(filterFn)
+}
+
+// listSessions returns all sessions currently known to the store that pass the
+// given filter function.
+func (db *BoltStore) listSessions(filterFn func(s *Session) bool) ([]*Session,
+	error) {
+
 	var sessions []*Session
 	err := db.View(func(tx *bbolt.Tx) error {
 		sessionBucket, err := getBucket(tx, sessionBucketKey)
@@ -399,6 +408,11 @@ func (db *BoltStore) ListSessions(filterFn func(s *Session) bool) ([]*Session, e
 		return nil, err
 	}
 
+	// Make sure to sort the sessions by creation time.
+	sort.Slice(sessions, func(i, j int) bool {
+		return sessions[i].CreatedAt.Before(sessions[j].CreatedAt)
+	})
+
 	return sessions, nil
 }
 

session/store_test.go

@@ -23,10 +23,16 @@ func TestBasicSessionStore(t *testing.T) {
 		_ = db.Close()
 	})
 
-	// Create a few sessions.
+	// Create a few sessions. We increment the time by one second between
+	// each session to ensure that the created at time is unique and hence
+	// that the ListSessions method returns the sessions in a deterministic
+	// order.
 	s1 := newSession(t, db, clock, "session 1")
+	clock.SetTime(testTime.Add(time.Second))
 	s2 := newSession(t, db, clock, "session 2")
+	clock.SetTime(testTime.Add(2 * time.Second))
 	s3 := newSession(t, db, clock, "session 3")
+	clock.SetTime(testTime.Add(3 * time.Second))
 	s4 := newSession(t, db, clock, "session 4")
 
 	// Persist session 1. This should now succeed.
@@ -50,6 +56,14 @@ func TestBasicSessionStore(t *testing.T) {
 	require.NoError(t, db.CreateSession(s2))
 	require.NoError(t, db.CreateSession(s3))
 
+	// Check that all sessions are returned in ListSessions.
+	sessions, err := db.ListSessions(nil)
+	require.NoError(t, err)
+	require.Equal(t, 3, len(sessions))
+	assertEqualSessions(t, s1, sessions[0])
+	assertEqualSessions(t, s2, sessions[1])
+	assertEqualSessions(t, s3, sessions[2])
+
 	// Ensure that we can retrieve each session by both its local pub key
 	// and by its ID.
 	for _, s := range []*Session{s1, s2, s3} {