feat: 기능 추가 과정중

tests/unit/chunk-recovery.test.ts

@@ -0,0 +1,60 @@
+import { describe, expect, it } from "vitest";
+
+import { decideChunkRecovery } from "../../src/application/use-cases/decide-chunk-recovery.ts";
+import type { StoragePort } from "../../src/application/ports/storage-port.ts";
+
+function memoryStorage(): StoragePort {
+  let value: unknown;
+  return {
+    read: () => ({ ok: true, value }),
+    write: (_key: string, next: unknown) => {
+      value = next;
+      return { ok: true };
+    },
+    remove: () => ({ ok: true }),
+  };
+}
+
+describe("controlled chunk recovery", () => {
+  it("records the release pair before allowing one reload", () => {
+    const storage = memoryStorage();
+    const input: Parameters<typeof decideChunkRecovery>[0] = {
+      failureKind: "CHUNK_LOAD_FAILURE",
+      manifestLoaded: true,
+      currentBuildId: "build-a",
+      currentReleaseId: "release-a",
+      activeBuildId: "build-b",
+      activeReleaseId: "release-b",
+      storage,
+    };
+    expect(decideChunkRecovery(input)).toEqual({
+      action: "reload-once",
+      releasePair: "build-a/release-a->build-b/release-b",
+    });
+    expect(decideChunkRecovery(input)).toEqual({
+      action: "support",
+      reason: "reload-already-attempted",
+    });
+  });
+
+  it.each([
+    [{ failureKind: "SERVER_FAILURE" }, "not-recoverable"],
+    [{ manifestLoaded: false }, "manifest-unavailable"],
+    [
+      { activeBuildId: "build-a", activeReleaseId: "release-a" },
+      "same-release",
+    ],
+  ])("stops when a recovery invariant fails: %#", (override, reason) => {
+    const result = decideChunkRecovery({
+      failureKind: "DEPLOY_MISMATCH",
+      manifestLoaded: true,
+      currentBuildId: "build-a",
+      currentReleaseId: "release-a",
+      activeBuildId: "build-b",
+      activeReleaseId: "release-b",
+      storage: memoryStorage(),
+      ...override,
+    });
+    expect(result).toEqual({ action: "support", reason });
+  });
+});