diff --git a/Sources/Containerization/IO/Writer.swift b/Sources/Containerization/IO/Writer.swift
index 9c2b4ff0..5eb2db26 100644
--- a/Sources/Containerization/IO/Writer.swift
+++ b/Sources/Containerization/IO/Writer.swift
@@ -19,4 +19,5 @@ import Foundation
 /// A type that writes the provided Data.
 public protocol Writer: Sendable {
     func write(_ data: Data) throws
+    func close() throws
 }
diff --git a/Sources/Integration/ContainerTests.swift b/Sources/Integration/ContainerTests.swift
index ff55dbba..e6668d38 100644
--- a/Sources/Integration/ContainerTests.swift
+++ b/Sources/Integration/ContainerTests.swift
@@ -72,6 +72,10 @@ extension IntegrationSuite {
             }
             self.data.append(data)
         }
+
+        func close() throws {
+            return
+        }
     }
 
     final class StdinBuffer: ReaderStream {