1 files changed, 103 insertions, 0 deletions
diff --git a/test/state.test.ts b/test/state.test.ts
new file mode 100644
index 0000000..a80fcfd
--- /dev/null
+++ b/test/state.test.ts
@@ -0,0 +1,103 @@
+import { mkdtempSync, readdirSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import {
+  EMPTY_NODE_STATE,
+  nodeState,
+  readServiceState,
+  removeNodeState,
+  serviceStatePath,
+  updateNodeState,
+  writeServiceState,
+} from "../src/state.js";
+
+let dir: string;
+
+beforeEach(() => {
+  dir = mkdtempSync(join(tmpdir(), "mattertimesync-state-"));
+});
+
+afterEach(() => {
+  rmSync(dir, { recursive: true, force: true });
+});
+
+describe("service state", () => {
+  it("returns empty state when the file does not exist", () => {
+    expect(readServiceState(join(dir, "missing.json"))).toEqual({ nodes: {} });
+  });
+
+  it("round-trips per-node state through disk", () => {
+    const path = serviceStatePath(dir);
+    const state = {
+      nodes: {
+        "12345678901234567890": {
+          lastSuccessfulConnection: "2026-07-26T20:00:00Z",
+          lastSuccessfulSync: "2026-07-26T20:00:02Z",
+          lastAttemptedSync: "2026-07-26T20:00:01Z",
+          lastError: null,
+        },
+        "2": { ...EMPTY_NODE_STATE, lastError: "unreachable" },
+      },
+    };
+    writeServiceState(path, state);
+    expect(readServiceState(path)).toEqual(state);
+  });
+
+  it("leaves no temporary file behind after writing", () => {
+    const path = serviceStatePath(dir);
+    writeServiceState(path, { nodes: {} });
+    expect(readdirSync(dir)).toEqual(["service-state.json"]);
+  });
+
+  it("returns empty state for a corrupt file instead of throwing", () => {
+    const path = join(dir, "corrupt.json");
+    writeFileSync(path, "{ this is not json");
+    expect(readServiceState(path)).toEqual({ nodes: {} });
+  });
+
+  it("drops malformed node keys and wrongly typed fields", () => {
+    const path = join(dir, "typed.json");
+    writeFileSync(
+      path,
+      JSON.stringify({
+        nodes: {
+          "not-a-node-id": { lastError: "x" },
+          "7": { lastError: ["array"], lastSuccessfulSync: "2026-07-26T20:00:02Z" },
+        },
+      }),
+    );
+    expect(readServiceState(path)).toEqual({
+      nodes: { "7": { ...EMPTY_NODE_STATE, lastSuccessfulSync: "2026-07-26T20:00:02Z" } },
+    });
+  });
+
+  it("merges patches into one node without touching others", () => {
+    const path = serviceStatePath(dir);
+    updateNodeState(path, 1n, { lastError: "boom" });
+    updateNodeState(path, 2n, { lastSuccessfulSync: "2026-07-26T20:00:02Z" });
+    updateNodeState(path, 1n, { lastAttemptedSync: "2026-07-26T20:00:01Z" });
+
+    const state = readServiceState(path);
+    expect(nodeState(state, 1n)).toEqual({
+      ...EMPTY_NODE_STATE,
+      lastError: "boom",
+      lastAttemptedSync: "2026-07-26T20:00:01Z",
+    });
+    expect(nodeState(state, 2n)).toEqual({
+      ...EMPTY_NODE_STATE,
+      lastSuccessfulSync: "2026-07-26T20:00:02Z",
+    });
+  });
+
+  it("removes a node's entry", () => {
+    const path = serviceStatePath(dir);
+    updateNodeState(path, 1n, { lastError: "boom" });
+    updateNodeState(path, 2n, {});
+    removeNodeState(path, 1n);
+
+    const state = readServiceState(path);
+    expect(Object.keys(state.nodes)).toEqual(["2"]);
+    expect(nodeState(state, 1n)).toEqual(EMPTY_NODE_STATE);
+  });
+});