test(lib): extract snapshot normalizer utility for cross-OS stability (#28356)

packages/opencode/test/lib/snapshot.ts

@@ -0,0 +1,73 @@
+// Shared normalization helpers for cross-OS-stable snapshot tests.
+//
+// Every snapshot test that captures subprocess output, file paths, or other
+// OS-flavored strings hits the same two issues:
+//   1. Bun emits CRLF line endings on Windows stderr; LF elsewhere.
+//   2. Path separators differ (\ on Windows, / on POSIX), and macOS's
+//      /var/folders symlink resolves to /private/var/folders.
+//
+// These helpers exist so each test doesn't reinvent the same regexes.
+//
+// Use individually for fine-grained control, or compose them via
+// `normalizeForSnapshot` for the common "snapshot subprocess output" path.
+import fs from "node:fs"
+import os from "node:os"
+
+const TMP = os.tmpdir()
+const REAL_TMP = fs.realpathSync(TMP)
+
+/**
+ * Collapses CRLF to LF. Bun's subprocess pipes emit native line endings —
+ * snapshots captured on macOS/Linux contain LF, so a Windows run without
+ * this step always diffs.
+ */
+export function stripCrlf(text: string): string {
+  return text.replaceAll("\r\n", "\n")
+}
+
+/**
+ * Converts Windows-style `\` separators to POSIX `/` so paths render
+ * identically across OSes. Use for path strings you want stable in a
+ * snapshot, not for filesystem operations.
+ */
+export function toPosixPath(p: string): string {
+  return p.replaceAll("\\", "/")
+}
+
+/**
+ * Strips both the OS-level `os.tmpdir()` and its realpath form (macOS
+ * `/var/folders` → `/private/var/folders`) from text, replacing each
+ * occurrence with `marker` (default `<TMPDIR>`).
+ */
+export function withTmpdirStripped(text: string, marker = "<TMPDIR>"): string {
+  return text.replaceAll(REAL_TMP, marker).replaceAll(TMP, marker)
+}
+
+/**
+ * Separator-agnostic match class for path-style strings. Use inside a
+ * larger regex when you want to match both `/` (POSIX) and `\` (Windows)
+ * boundaries — e.g. `<TMPDIR>${PATH_SEP}oc-cli-[a-z0-9]+`.
+ */
+export const PATH_SEP = "[/\\\\]"
+
+/**
+ * One-shot normalization for the common case: strip CRLF, strip tmpdir,
+ * then apply any caller-supplied path regex substitutions. Does NOT
+ * blanket-replace `\` with `/` — that would mangle non-path backslash
+ * content (regex literals in help text, etc.). Use `toPosixPath` or
+ * `PATH_SEP` in your own regex when you need separator agnosticism.
+ */
+export function normalizeForSnapshot(
+  text: string,
+  options?: {
+    readonly tmpdirMarker?: string
+    readonly pathReplacements?: ReadonlyArray<readonly [RegExp, string]>
+  },
+): string {
+  let out = stripCrlf(text)
+  out = withTmpdirStripped(out, options?.tmpdirMarker)
+  for (const [pattern, replacement] of options?.pathReplacements ?? []) {
+    out = out.replace(pattern, replacement)
+  }
+  return out
+}