refactor(core): extract shared dedup helpers

src/plugin-sdk/runtime.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it, vi } from "vitest";
+import type { RuntimeEnv } from "../runtime.js";
+import { resolveRuntimeEnv } from "./runtime.js";
+
+describe("resolveRuntimeEnv", () => {
+  it("returns provided runtime when present", () => {
+    const runtime: RuntimeEnv = {
+      log: vi.fn(),
+      error: vi.fn(),
+      exit: vi.fn(() => {
+        throw new Error("exit");
+      }),
+    };
+    const logger = {
+      info: vi.fn(),
+      error: vi.fn(),
+    };
+
+    const resolved = resolveRuntimeEnv({ runtime, logger });
+
+    expect(resolved).toBe(runtime);
+    expect(logger.info).not.toHaveBeenCalled();
+    expect(logger.error).not.toHaveBeenCalled();
+  });
+
+  it("creates logger-backed runtime when runtime is missing", () => {
+    const logger = {
+      info: vi.fn(),
+      error: vi.fn(),
+    };
+
+    const resolved = resolveRuntimeEnv({ logger });
+    resolved.log?.("hello %s", "world");
+    resolved.error?.("bad %d", 7);
+
+    expect(logger.info).toHaveBeenCalledWith("hello world");
+    expect(logger.error).toHaveBeenCalledWith("bad 7");
+  });
+});