test(cli): dedupe runtime capture fixtures across command specs

src/cli/test-runtime-capture.ts

@@ -0,0 +1,28 @@
+import type { RuntimeEnv } from "../runtime.js";
+
+export type CliRuntimeCapture = {
+  runtimeLogs: string[];
+  runtimeErrors: string[];
+  defaultRuntime: Pick<RuntimeEnv, "log" | "error" | "exit">;
+  resetRuntimeCapture: () => void;
+};
+
+export function createCliRuntimeCapture(): CliRuntimeCapture {
+  const runtimeLogs: string[] = [];
+  const runtimeErrors: string[] = [];
+  return {
+    runtimeLogs,
+    runtimeErrors,
+    defaultRuntime: {
+      log: (msg: string) => runtimeLogs.push(msg),
+      error: (msg: string) => runtimeErrors.push(msg),
+      exit: (code: number) => {
+        throw new Error(`__exit__:${code}`);
+      },
+    },
+    resetRuntimeCapture: () => {
+      runtimeLogs.length = 0;
+      runtimeErrors.length = 0;
+    },
+  };
+}