Stage locked Windows binary updates

tests/release_scripts.rs

@@ -298,12 +298,30 @@ fn windows_prebuilt_install_requires_client_but_not_bench() {
     assert!(ps1.contains("throw \"prebuilt archive missing dosh-client.exe\""));
     assert!(ps1.contains("-Filter \"dosh-bench.exe\""));
     assert!(ps1.contains("if ($bench)"));
+    assert!(ps1.contains("Install-Binary $client.FullName (Join-Path $bindir \"dosh.exe\")"));
+    assert!(!ps1.contains("Install-Binary (Join-Path $bindir \"dosh-client.exe\")"));
     assert!(
         !ps1.contains("throw \"prebuilt archive missing dosh-bench.exe\""),
         "Windows prebuilt install should not fall back to source just because dosh-bench is absent"
     );
 }
 
+#[test]
+fn windows_installer_stages_locked_binary_replacements() {
+    let ps1 = include_str!("../install.ps1");
+    assert!(ps1.contains("function Start-DeferredBinaryReplacement"));
+    assert!(ps1.contains("$pending = \"$Destination.pending.$PID\""));
+    assert!(ps1.contains("Move-Item -LiteralPath $tmp -Destination $pending -Force"));
+    assert!(ps1.contains("Start-DeferredBinaryReplacement $pending $Destination"));
+    assert!(ps1.contains("binary is in use; staged replacement"));
+    assert!(ps1.contains("for (`$i = 0; `$i -lt 3600; `$i++)"));
+    assert!(ps1.contains(
+        "Move-Item -LiteralPath `$payload.Pending -Destination `$payload.Destination -Force"
+    ));
+    assert!(ps1.contains("[System.Text.Encoding]::Unicode.GetBytes($script)"));
+    assert!(ps1.contains("Start-Process -FilePath $ps"));
+}
+
 #[test]
 fn windows_installer_adds_user_path_idempotently() {
     let ps1 = include_str!("../install.ps1");