feat(deploy): notify clients of new releases

lib/deployment/version.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  hasDeploymentChanged,
+  normalizeDeploymentId,
+} from "./version";
+
+describe("deployment version comparison", () => {
+  it("normalizes identifiers before comparing them", () => {
+    expect(normalizeDeploymentId("  release-2  ")).toBe("release-2");
+    expect(normalizeDeploymentId("   ")).toBeNull();
+    expect(hasDeploymentChanged("release-1", " release-2 ")).toBe(true);
+  });
+
+  it("does not announce the initial or unchanged deployment", () => {
+    expect(hasDeploymentChanged(null, "release-2")).toBe(false);
+    expect(hasDeploymentChanged("release-2", "release-2")).toBe(false);
+    expect(hasDeploymentChanged("release-2", "")).toBe(false);
+  });
+});