snapshot of https://github.com/zulip/zulip.git @ 48c69911c7dd4e03b20552eb3bd77ad8151c1357 (2026-09-15)

web/tests/list_cursor.test.cjs

@@ -0,0 +1,161 @@
+"use strict";
+
+const assert = require("node:assert/strict");
+
+const {zrequire} = require("./lib/namespace.cjs");
+const {run_test, noop} = require("./lib/test.cjs");
+const blueslip = require("./lib/zblueslip.cjs");
+const {$} = require("./lib/zjquery.cjs");
+
+const {ListCursor} = zrequire("list_cursor");
+
+function basic_conf({first_key, prev_key, next_key}) {
+    const list = {
+        scroll_container_selector: "whatever",
+        find_li() {},
+        first_key,
+        prev_key,
+        next_key,
+    };
+
+    const conf = {
+        list,
+        highlight_class: "highlight",
+    };
+
+    return conf;
+}
+
+run_test("misc errors", ({override}) => {
+    const conf = basic_conf({
+        first_key: () => undefined,
+        prev_key: /* istanbul ignore next */ () => undefined,
+        next_key: /* istanbul ignore next */ () => undefined,
+    });
+
+    const cursor = new ListCursor(conf);
+
+    // Test that we just ignore empty
+    // lists for unknown keys.
+    override(conf.list, "find_li", ({key, force_render}) => {
+        assert.equal(key, "nada");
+        assert.equal(force_render, true);
+        return [];
+    });
+
+    cursor.get_row("nada");
+
+    blueslip.expect("error", "Caller is not checking keys for ListCursor.go_to");
+    cursor.go_to(undefined);
+
+    blueslip.expect("error", "Cannot highlight key for ListCursor");
+    cursor.go_to("nada");
+
+    cursor.prev();
+    cursor.next();
+});
+
+run_test("single item list", ({override}) => {
+    const valid_key = "42";
+
+    const conf = basic_conf({
+        first_key: /* istanbul ignore next */ () => valid_key,
+        next_key: () => undefined,
+        prev_key: () => undefined,
+    });
+    const cursor = new ListCursor(conf);
+
+    const $li_stub = {
+        length: 1,
+        addClass() {},
+    };
+
+    override(conf.list, "find_li", () => $li_stub);
+    override(cursor, "adjust_scroll", noop);
+
+    cursor.set_is_highlight_visible(true);
+    cursor.go_to(valid_key);
+
+    // Test prev/next, which should just silently do nothing.
+    cursor.prev();
+    cursor.next();
+
+    // The next line is also a noop designed to just give us test
+    // coverage.
+    cursor.go_to(valid_key);
+});
+
+run_test("multiple item list", ({override}) => {
+    const conf = basic_conf({
+        first_key: /* istanbul ignore next */ () => 1,
+        next_key: (key) => (key < 3 ? key + 1 : undefined),
+        prev_key: (key) => (key > 1 ? key - 1 : undefined),
+    });
+    const cursor = new ListCursor(conf);
+    override(cursor, "adjust_scroll", noop);
+
+    function li(key) {
+        return $.create(`item-${key}`);
+    }
+
+    const list_items = {
+        1: li(1),
+        2: li(2),
+        3: li(3),
+    };
+
+    override(conf.list, "find_li", ({key}) => list_items[key]);
+
+    cursor.go_to(2);
+    assert.equal(cursor.get_key(), 2);
+    assert.ok(!list_items[1].hasClass("highlight"));
+    // Selection is not highlighted until we want it to.
+    assert.ok(!list_items[2].hasClass("highlight"));
+    assert.ok(!list_items[3].hasClass("highlight"));
+
+    // Current selection is not highlighted until user wants
+    // to move the cursor.
+    // Also, cursor doesn't move if the selection was not
+    // previously highlighted.
+    cursor.next();
+    assert.equal(cursor.get_key(), 2);
+    assert.ok(!list_items[1].hasClass("highlight"));
+    assert.ok(list_items[2].hasClass("highlight"));
+    assert.ok(!list_items[3].hasClass("highlight"));
+    // Reset state
+    cursor.set_is_highlight_visible(false);
+    cursor.prev();
+    assert.equal(cursor.get_key(), 2);
+    assert.ok(!list_items[1].hasClass("highlight"));
+    assert.ok(list_items[2].hasClass("highlight"));
+    assert.ok(!list_items[3].hasClass("highlight"));
+
+    cursor.next();
+    cursor.next();
+    cursor.next();
+
+    assert.equal(cursor.get_key(), 3);
+    assert.ok(!list_items[1].hasClass("highlight"));
+    assert.ok(!list_items[2].hasClass("highlight"));
+    assert.ok(list_items[3].hasClass("highlight"));
+
+    cursor.prev();
+    cursor.prev();
+    cursor.prev();
+
+    assert.equal(cursor.get_key(), 1);
+    assert.ok(list_items[1].hasClass("highlight"));
+    assert.ok(!list_items[2].hasClass("highlight"));
+    assert.ok(!list_items[3].hasClass("highlight"));
+
+    override(conf.list, "find_li", () => list_items[1]);
+    cursor.redraw();
+    assert.ok(list_items[1].hasClass("highlight"));
+    assert.ok(!list_items[2].hasClass("highlight"));
+    assert.ok(!list_items[3].hasClass("highlight"));
+
+    cursor.clear();
+    assert.equal(cursor.get_key(), undefined);
+    cursor.redraw();
+    assert.ok(!list_items[1].hasClass("highlight"));
+});