kvserver: add LookupNextReplica test

Release note: none
Epic: none

pkg/kv/kvserver/store_replica_btree_test.go

@@ -87,7 +87,7 @@ func TestStoreReplicaBTree_VisitKeyRange(t *testing.T) {
 	})
 }
 
-func TestStoreReplicaBTree_LookupPrecedingReplica(t *testing.T) {
+func TestStoreReplicaBTree_LookupPrecedingAndNextReplica(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 
 	ctx := context.Background()
@@ -116,25 +116,29 @@ func TestStoreReplicaBTree_LookupPrecedingReplica(t *testing.T) {
 	require.Zero(t, b.ReplaceOrInsertReplica(ctx, repl5))
 
 	for i, tc := range []struct {
-		key     string
-		expRepl *Replica
+		key      string
+		preRepl  *Replica
+		nextRepl *Replica
 	}{
-		{"", nil},
-		{"a", nil},
-		{"aa", nil},
-		{"b", repl2},
-		{"bb", repl2},
-		{"c", repl3},
-		{"cc", repl3},
-		{"d", repl3},
-		{"dd", repl3},
-		{"e", repl3},
-		{"ee", repl3},
-		{"f", repl5},
-		{"\xff\xff", repl5},
+		{"", nil, repl2},
+		{"a", nil, repl2},
+		{"aa", nil, repl3},
+		{"b", repl2, repl3},
+		{"bb", repl2, repl5},
+		{"c", repl3, repl5},
+		{"cc", repl3, repl5},
+		{"d", repl3, repl5},
+		{"dd", repl3, repl5},
+		{"e", repl3, repl5},
+		{"ee", repl3, nil},
+		{"f", repl5, nil},
+		{"\xff\xff", repl5, nil},
 	} {
-		if repl := b.LookupPrecedingReplica(ctx, roachpb.RKey(tc.key)); repl != tc.expRepl {
-			t.Errorf("%d: expected replica %v; got %v", i, tc.expRepl, repl)
+		if got, want := b.LookupPrecedingReplica(ctx, roachpb.RKey(tc.key)), tc.preRepl; got != want {
+			t.Errorf("%d: expected preceding replica %v; got %v", i, want, got)
+		}
+		if got, want := b.LookupNextReplica(ctx, roachpb.RKey(tc.key)), tc.nextRepl; got != want {
+			t.Errorf("%d: expected next replica %v; got %v", i, want, got)
 		}
 	}
 }