Merge PR #249: refactor: extract backend settings helpers

Author: ndycode

test/backend-settings-helpers.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from "vitest";
+import {
+	backendSettingsEqual,
+	backendSettingsSnapshot,
+	buildBackendConfigPatch,
+	buildBackendSettingsPreview,
+	clampBackendNumberForTests,
+	cloneBackendPluginConfig,
+	formatBackendNumberValue,
+} from "../lib/codex-manager/backend-settings-helpers.js";
+
+describe("backend settings helpers", () => {
+	it("clones fallback chains defensively", () => {
+		const cloned = cloneBackendPluginConfig({ unsupportedCodexFallbackChain: { a: ["b"] } } as never);
+		expect(cloned.unsupportedCodexFallbackChain).toEqual({ a: ["b"] });
+		expect(cloned.unsupportedCodexFallbackChain).not.toBe((({ unsupportedCodexFallbackChain: { a: ["b"] } } as never).unsupportedCodexFallbackChain));
+	});
+
+	it("formats and clamps backend numeric values", () => {
+		expect(formatBackendNumberValue({ unit: "percent" } as never, 4.6)).toBe("5%");
+		expect(formatBackendNumberValue({ unit: "count" } as never, 2.2)).toBe("2");
+		expect(clampBackendNumberForTests("fetchTimeoutMs", 10)).toBeGreaterThanOrEqual(1000);
+	});
+
+	it("builds snapshots, equality, preview and patches", () => {
+		const left = { fetchTimeoutMs: 60000, streamStallTimeoutMs: 45000, liveAccountSync: true, sessionAffinity: true, preemptiveQuotaEnabled: true, preemptiveQuotaRemainingPercent5h: 5, preemptiveQuotaRemainingPercent7d: 5 } as never;
+		const right = { ...left } as never;
+		expect(backendSettingsSnapshot(left)).toEqual(backendSettingsSnapshot(right));
+		expect(backendSettingsEqual(left, right)).toBe(true);
+		const preview = buildBackendSettingsPreview(left, { theme: {} } as never, "fetchTimeoutMs", { highlightPreviewToken: (text) => `[${text}]` });
+		expect(preview.label).toContain("live sync");
+		expect(preview.hint).toContain("timeouts");
+		expect(buildBackendConfigPatch({ ...left, fetchTimeoutMs: 10 } as never)).toHaveProperty("fetchTimeoutMs");
+	});
+});