plan 8: fuzz decoders; fold ẞ and invalid UTF-8 correctly, refuse non-UTF-8 paths in krino new

1 files changed, 27 insertions, 1 deletions

diff --git a/internal/sexp/fuzz_test.go b/internal/sexp/fuzz_test.go
index 01d436b..c64145a 100644
--- a/internal/sexp/fuzz_test.go
+++ b/internal/sexp/fuzz_test.go
@@ -2,7 +2,10 @@
 
 package sexp
 
-import "testing"
+import (
+	"testing"
+	"unicode/utf8"
+)
 
 // FuzzParse checks that Parse never panics and that every node it returns
 // spans valid bytes, with lists pointing at their own parentheses.
@@ -25,3 +28,26 @@ func FuzzParse(f *testing.F) {
 		})
 	})
 }
+
+// FuzzQuoteRoundTrip: Quote gives one string atom that parses back to
+// exactly the text quoted, for any valid UTF-8 - quotes, backslashes and
+// newlines included. krino new writes a directory's path into its config
+// with Quote; config files are UTF-8 text, so krino new refuses a path that
+// is not, and invalid UTF-8 is out of this property's scope.
+func FuzzQuoteRoundTrip(f *testing.F) {
+	for _, s := range []string{"plain", `with "quotes"`, `back\slash`, "new\nline", "zażółć", "", "\xff", `\bacme\b`} {
+		f.Add(s)
+	}
+	f.Fuzz(func(t *testing.T, s string) {
+		if !utf8.ValidString(s) {
+			return
+		}
+		nodes, err := Parse("f", []byte(Quote(s)))
+		if err != nil {
+			t.Fatalf("Quote(%q) = %s does not parse: %v", s, Quote(s), err)
+		}
+		if len(nodes) != 1 || nodes[0].Kind != String || nodes[0].Text != s {
+			t.Fatalf("Quote(%q) = %s reads back as %+v", s, Quote(s), nodes)
+		}
+	})
+}