refactor: cleanup

src/lib/window-decorations.test.mjs

@@ -0,0 +1,116 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import {
+  DEFAULT_DECORATION_LAYOUT,
+  parseDecorationLayout,
+} from "./window-decorations.ts";
+
+/**
+ * The app draws its own titlebar on Linux, so it owns the window controls —
+ * and where they go is a desktop-wide user preference. This parser is the only
+ * thing standing between that preference and the buttons we render, and only
+ * GNOME can be exercised on the machine this was written on, so KDE's real
+ * layout strings are pinned here instead.
+ */
+
+test("GNOME's default puts every control on the right", () => {
+  assert.deepEqual(parseDecorationLayout(":minimize,maximize,close"), {
+    left: [],
+    right: ["minimize", "maximize", "close"],
+  });
+});
+
+test("a left-hand layout is honored", () => {
+  // GNOME users who prefer macOS ordering set exactly this.
+  assert.deepEqual(parseDecorationLayout("close,minimize,maximize:"), {
+    left: ["close", "minimize", "maximize"],
+    right: [],
+  });
+});
+
+test("controls can be split across both sides", () => {
+  assert.deepEqual(parseDecorationLayout("close:minimize,maximize"), {
+    left: ["close"],
+    right: ["minimize", "maximize"],
+  });
+});
+
+test("GTK's own default drops the appmenu it cannot draw", () => {
+  assert.deepEqual(parseDecorationLayout("appmenu:close"), {
+    left: [],
+    right: ["close"],
+  });
+});
+
+test("non-button tokens are ignored rather than rendered", () => {
+  // `icon`, `menu`, `appmenu` and `spacer` are all legal GTK tokens for things
+  // this titlebar does not draw.
+  assert.deepEqual(parseDecorationLayout("icon,menu:spacer,close"), {
+    left: [],
+    right: ["close"],
+  });
+});
+
+test("KDE's extra decoration buttons are ignored", () => {
+  // KWin offers buttons GTK has no concept of. kde-gtk-config maps what it can
+  // and may pass these through; rendering an unknown box would be worse than
+  // dropping it, which is what GTK itself does.
+  assert.deepEqual(
+    parseDecorationLayout(
+      "menu,applicationmenu:shade,keepabove,keepbelow,help,minimize,maximize,close",
+    ),
+    { left: [], right: ["minimize", "maximize", "close"] },
+  );
+});
+
+test("a duplicated control is rendered once", () => {
+  assert.deepEqual(parseDecorationLayout("close:close,minimize"), {
+    left: ["close"],
+    right: ["minimize"],
+  });
+});
+
+test("whitespace and capitalization are tolerated", () => {
+  assert.deepEqual(parseDecorationLayout(" : Minimize , CLOSE "), {
+    left: [],
+    right: ["minimize", "close"],
+  });
+});
+
+test("a string with no colon is entirely the left side, as GTK reads it", () => {
+  // `g_strsplit(layout, ":", 2)` leaves the right-hand token NULL, so GTK puts
+  // every button on the left. No mainstream desktop emits this, but matching
+  // GTK is the only defensible reading.
+  assert.deepEqual(parseDecorationLayout("minimize,close"), {
+    left: ["minimize", "close"],
+    right: [],
+  });
+});
+
+test("only the first colon splits the sides", () => {
+  // GTK's split has a limit of 2, so the second colon is not a separator: the
+  // right side becomes the single token "minimize:maximize", which matches no
+  // button name and is dropped — exactly as GTK drops it.
+  assert.deepEqual(parseDecorationLayout("close:minimize:maximize"), {
+    left: ["close"],
+    right: [],
+  });
+});
+
+test("missing, empty and unusable layouts fall back to the default", () => {
+  const fallback = { left: [], right: ["minimize", "maximize", "close"] };
+  for (const input of [null, undefined, "", "   "]) {
+    assert.deepEqual(parseDecorationLayout(input), fallback, `input: ${input}`);
+  }
+  // A layout naming only buttons we cannot draw would otherwise leave the user
+  // with no way to close the window.
+  assert.deepEqual(parseDecorationLayout("appmenu:spacer"), fallback);
+  assert.deepEqual(parseDecorationLayout(":"), fallback);
+});
+
+test("the documented default parses to the default", () => {
+  assert.deepEqual(parseDecorationLayout(DEFAULT_DECORATION_LAYOUT), {
+    left: [],
+    right: ["minimize", "maximize", "close"],
+  });
+});