2 files changed, 36 insertions, 4 deletions
diff --git a/test/lit/passes/string-lowering.js b/test/lit/passes/string-lowering.js
new file mode 100644
index 000000000..105970bcc
--- /dev/null
+++ b/test/lit/passes/string-lowering.js
@@ -0,0 +1,17 @@
+var filename = process.argv[2];
+var module = new WebAssembly.Module(require('fs').readFileSync(filename));
+var sections = WebAssembly.Module.customSections(module, 'string.consts');
+var array = new Uint8Array(sections[0]);
+var string = new TextDecoder('utf-8').decode(array);
+
+function standardizeEncoding(s) {
+  // Different node.js versions print differently, so we must standardize to
+  // pass tests in all places. In particular at some point node.js started to
+  // abbreviate \u0000 as \x00 (both of which are valid).
+  return s.replace('\\u0000', '\\x00');
+}
+
+console.log("string:", standardizeEncoding(string));
+
+var json = JSON.stringify(JSON.parse(string));
+console.log("JSON:", standardizeEncoding(json));
diff --git a/test/lit/passes/string-lowering.wast b/test/lit/passes/string-lowering.wast
index 628092d1c..43d30fc64 100644
--- a/test/lit/passes/string-lowering.wast
+++ b/test/lit/passes/string-lowering.wast
@@ -2,8 +2,6 @@
 ;; operations are tested in string-gathering.wast (which is auto-updated, unlike
 ;; this which is manual).
 
-;; RUN: foreach %s %t wasm-opt --string-lowering -all -S -o - | filecheck %s
-
 (module
   (func $consts
     (drop
@@ -15,9 +13,26 @@
     (drop
       (string.const "foo")
     )
+    (drop
+      (string.const "needs\tescaping\00.'#%\"- .\r\n\\.ꙮ")
+    )
   )
 )
 
-;; The custom section should contain foo and bar, and foo only once.
-;; CHECK: custom section "string.consts", size 13, contents: "[\"bar\",\"foo\"]"
+;; The custom section should contain foo and bar, and foo only once, and the
+;; string with \t should be escaped.
+;;
+;; RUN: wasm-opt %s --string-lowering -all -S -o - | filecheck %s
+;;
+;; CHECK: custom section "string.consts", size 59, contents: "[\"bar\",\"foo\",\"needs\\tescaping\\u0000.'#%\\\"- .\\r\\n\\\\.\\ua66e\"]"
+
+;; The custom section should parse OK using JSON.parse from node.
+;; (Note we run --remove-unused-module-elements to remove externref-using
+;; imports, which require a newer version of node.)
+;;
+;; RUN: wasm-opt %s --string-lowering --remove-unused-module-elements -all -o %t.wasm
+;; RUN: node %S/string-lowering.js %t.wasm | filecheck %s --check-prefix=CHECK-JS
+;;
+;; CHECK-JS: string: ["bar","foo","needs\tescaping\x00.'#%\"- .\r\n\\.\ua66e"]
+;; CHECK-JS: JSON: ["bar","foo","needs\tescaping\x00.'#%\"- .\r\n\\.ꙮ"]