diff --git a/.github/workflows/test-on-pull-request.yml b/.github/workflows/test-on-pull-request.yml
index 5850c5f4..58175a33 100644
--- a/.github/workflows/test-on-pull-request.yml
+++ b/.github/workflows/test-on-pull-request.yml
@@ -18,7 +18,7 @@ jobs:
         run: npm run test
       - name: Upload test results
         if: always()
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: playwright-report
           path: playwright-report
diff --git a/packages/wasi/tests/libstd.spec.ts b/packages/wasi/tests/libstd.spec.ts
index 93d734b2..a5151818 100644
--- a/packages/wasi/tests/libstd.spec.ts
+++ b/packages/wasi/tests/libstd.spec.ts
@@ -57,6 +57,7 @@ for (const name of wasmFiles) {
 
           let stderr = "";
           let stdout = "";
+          let stdinBytes = new TextEncoder().encode(stdin ?? "");
 
           return W.start(
             fetch(url),
@@ -69,11 +70,10 @@ for (const name of wasmFiles) {
               stderr: (s) => {
                 stderr += s;
               },
-              stdin: (maxByteLength: number) => {
-                const index = Math.floor(maxByteLength / 2) + 1;
-                const retvalue = stdin.slice(0, index);
-                stdin = stdin.slice(index);
-                return retvalue;
+              stdin: (maxByteLength) => {
+                const chunk = stdinBytes.slice(0, maxByteLength);
+                stdinBytes = stdinBytes.slice(maxByteLength);
+                return new TextDecoder().decode(chunk);
               },
               fs,
             })