Files
gasm-sdk/format/fuzz_test.go
2026-09-26 11:08:43 +02:00

54 lines
1.7 KiB
Go

// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: BSD-3-Clause
package format
import (
"os"
"path/filepath"
"testing"
"sourcedock.dev/petrbalvin/gasm-sdk/parser"
)
// FuzzFormatIdempotency hammers the formatter with arbitrary input. The
// contract: formatting twice equals formatting once, and input that parses
// cleanly still parses cleanly after formatting. The seed corpus carries the
// repository's kernels, so a plain `go test` run replays every seed as a
// regression case and CI exercises them without any fuzzing budget.
func FuzzFormatIdempotency(f *testing.F) {
for _, pattern := range []string{
"../testdata/*.s",
"../testdata/verify/*.s",
} {
files, _ := filepath.Glob(pattern)
for _, path := range files {
if b, err := os.ReadFile(path); err == nil {
f.Add(string(b))
}
}
}
f.Add("TEXT ·f(SB), NOSPLIT, $0\n\tMOVQ AX, BX\n\tRET\n")
f.Add("TEXT ·f(SB),NOSPLIT,$0\n\tMOVQ AX,BX\n\n\n\tRET\n")
f.Add("garbage ### ???\n")
// Line-ending whitespace at the edge of a comment: a CR followed by more
// trailing whitespace once survived the first pass and disappeared on
// re-lexing, so formatting was not idempotent.
f.Add("//\r ")
f.Add("// loop \r\t\nMOVQ AX, BX\n")
f.Add("TEXT ·f(SB), NOSPLIT, $0 // tail\r\n\tMOVQ AX, BX\r\n\tRET\r\n")
f.Fuzz(func(t *testing.T, src string) {
once := Source(src)
twice := Source(once)
if once != twice {
t.Fatalf("formatting is not idempotent:\nfirst: %q\nsecond: %q", once, twice)
}
if _, errs := parser.Parse("in.s", src); len(errs) == 0 {
if _, errs := parser.Parse("out.s", once); len(errs) > 0 {
t.Fatalf("formatted output of clean input does not parse: %v\n%s", errs[0], once)
}
}
})
}