a file's name is folded once, not once per name test

Folding is the expensive half of a name test on a name with diacritics,
and every name test of every rule folded the same name again: on Polish
names it was most of the matching work. The per-file facts memoise it,
which is where one file's work belongs - the object is per file and per
goroutine, so no lock.

  4000 Polish names, twelve rules with name tests: 0.33s -> 0.13s

1 files changed, 2 insertions, 0 deletions

diff --git a/internal/engine/engine_test.go b/internal/engine/engine_test.go
index 89ea6f0..85679dc 100644
--- a/internal/engine/engine_test.go
+++ b/internal/engine/engine_test.go
@@ -12,6 +12,7 @@ import (
 
 	"git.labunix.xyz/krino/internal/cond"
 	"git.labunix.xyz/krino/internal/config"
+	"git.labunix.xyz/krino/internal/norm"
 )
 
 // sandbox gives a test its own HOME with no XDG overrides and returns it.
@@ -55,6 +56,7 @@ func (f fakeFacts) Now() time.Time                                      { return
 func (f fakeFacts) ContentContains(cond.Options, []string) (int, error) { return -1, nil }
 func (f fakeFacts) Duplicate([]string) (string, bool, error)            { return "", false, nil }
 func (f fakeFacts) Matched() (bool, bool)                               { return false, false }
+func (f fakeFacts) Folded(subj string) norm.Folded                      { return norm.FoldMapped(subj) }
 
 var _ cond.Facts = fakeFacts{}