feat: add settings defaults and validation with unit tests

test/settings.test.js

@@ -0,0 +1,80 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { DEFAULT_SETTINGS } from "../lib/defaults.js";
+import { mergeSettings } from "../lib/settings.js";
+
+test("empty object yields the defaults", () => {
+  assert.deepEqual(mergeSettings({}), DEFAULT_SETTINGS);
+});
+
+test("null and undefined yield the defaults", () => {
+  assert.deepEqual(mergeSettings(null), DEFAULT_SETTINGS);
+  assert.deepEqual(mergeSettings(undefined), DEFAULT_SETTINGS);
+});
+
+test("a non-object yields the defaults", () => {
+  assert.deepEqual(mergeSettings("nonsense"), DEFAULT_SETTINGS);
+  assert.deepEqual(mergeSettings(42), DEFAULT_SETTINGS);
+});
+
+test("valid stored values are preserved", () => {
+  assert.deepEqual(
+    mergeSettings({
+      model: "auto",
+      temporaryChat: true,
+      webSearch: true,
+      openIn: "new-window",
+      promptTemplate: "Explain: {query}",
+    }),
+    {
+      model: "auto",
+      temporaryChat: true,
+      webSearch: true,
+      openIn: "new-window",
+      promptTemplate: "Explain: {query}",
+    },
+  );
+});
+
+test("missing keys fall back individually", () => {
+  const merged = mergeSettings({ model: "auto" });
+  assert.equal(merged.model, "auto");
+  assert.equal(merged.temporaryChat, DEFAULT_SETTINGS.temporaryChat);
+  assert.equal(merged.promptTemplate, DEFAULT_SETTINGS.promptTemplate);
+});
+
+test("unknown keys are dropped", () => {
+  const merged = mergeSettings({ model: "auto", nope: "gone", openInn: "typo" });
+  assert.deepEqual(Object.keys(merged).sort(), Object.keys(DEFAULT_SETTINGS).sort());
+  assert.equal("nope" in merged, false);
+});
+
+test("wrong types fall back to the default", () => {
+  const merged = mergeSettings({
+    model: 123,
+    temporaryChat: "yes",
+    webSearch: 1,
+    promptTemplate: [],
+  });
+  assert.equal(merged.model, DEFAULT_SETTINGS.model);
+  assert.equal(merged.temporaryChat, DEFAULT_SETTINGS.temporaryChat);
+  assert.equal(merged.webSearch, DEFAULT_SETTINGS.webSearch);
+  assert.equal(merged.promptTemplate, DEFAULT_SETTINGS.promptTemplate);
+});
+
+test("an out-of-range openIn falls back to the default", () => {
+  assert.equal(mergeSettings({ openIn: "teleport" }).openIn, DEFAULT_SETTINGS.openIn);
+  assert.equal(mergeSettings({ openIn: "" }).openIn, DEFAULT_SETTINGS.openIn);
+});
+
+test("each documented openIn value is accepted", () => {
+  for (const value of ["new-tab", "background-tab", "new-window"]) {
+    assert.equal(mergeSettings({ openIn: value }).openIn, value);
+  }
+});
+
+test("mergeSettings does not mutate DEFAULT_SETTINGS", () => {
+  mergeSettings({ model: "mutated" });
+  assert.equal(DEFAULT_SETTINGS.model, "");
+});