refactor(test): dedupe gateway env setup and add env util coverage

src/test-utils/env.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "vitest";
+import { captureEnv, captureFullEnv, withEnv, withEnvAsync } from "./env.js";
+
+describe("env test utils", () => {
+  it("captureEnv restores mutated keys", () => {
+    const keyA = "OPENCLAW_ENV_TEST_A";
+    const keyB = "OPENCLAW_ENV_TEST_B";
+    const snapshot = captureEnv([keyA, keyB]);
+    const prevA = process.env[keyA];
+    const prevB = process.env[keyB];
+    process.env[keyA] = "mutated";
+    delete process.env[keyB];
+
+    snapshot.restore();
+
+    expect(process.env[keyA]).toBe(prevA);
+    expect(process.env[keyB]).toBe(prevB);
+  });
+
+  it("captureFullEnv restores added keys and baseline values", () => {
+    const key = "OPENCLAW_ENV_TEST_ADDED";
+    const prevHome = process.env.HOME;
+    const snapshot = captureFullEnv();
+    process.env[key] = "1";
+    delete process.env.HOME;
+
+    snapshot.restore();
+
+    expect(process.env[key]).toBeUndefined();
+    expect(process.env.HOME).toBe(prevHome);
+  });
+
+  it("withEnv applies values only inside callback", () => {
+    const key = "OPENCLAW_ENV_TEST_SYNC";
+    const prev = process.env[key];
+
+    const seen = withEnv({ [key]: "inside" }, () => process.env[key]);
+
+    expect(seen).toBe("inside");
+    expect(process.env[key]).toBe(prev);
+  });
+
+  it("withEnvAsync restores values when callback throws", async () => {
+    const key = "OPENCLAW_ENV_TEST_ASYNC";
+    const prev = process.env[key];
+
+    await expect(
+      withEnvAsync({ [key]: "inside" }, async () => {
+        expect(process.env[key]).toBe("inside");
+        throw new Error("boom");
+      }),
+    ).rejects.toThrow("boom");
+
+    expect(process.env[key]).toBe(prev);
+  });
+});