1 files changed, 45 insertions, 0 deletions
diff --git a/frontend/tests/Reader.test.ts b/frontend/tests/Reader.test.ts
new file mode 100644
index 0000000..e12d69b
--- /dev/null
+++ b/frontend/tests/Reader.test.ts
@@ -0,0 +1,45 @@
+import { Layout, type PageFragment } from '$gql/graphql';
+import { partition, type Chunk } from '$lib/Reader';
+import { expect, test } from 'vitest';
+
+const normalAttrs = { aspectRatio: 0.7, width: 140, height: 200 };
+const wideAttrs = { aspectRatio: 1.4, width: 280, height: 200 };
+
+const pages: PageFragment[] = [
+	{ id: 0, path: '000.png', image: { id: 0, hash: '0', ...normalAttrs } },
+	{ id: 1, path: '001.png', image: { id: 1, hash: '1', ...normalAttrs } },
+	{ id: 2, path: '002.png', image: { id: 2, hash: '2', ...normalAttrs } },
+	{ id: 3, path: '003.png', image: { id: 3, hash: '3', ...normalAttrs } },
+	{ id: 4, path: '004.png', image: { id: 4, hash: '4', ...wideAttrs } },
+	{ id: 5, path: '005.png', image: { id: 5, hash: '5', ...normalAttrs } },
+	{ id: 6, path: '006.png', image: { id: 6, hash: '6', ...normalAttrs } }
+];
+
+const ids = (chunks: Chunk[]) =>
+	chunks.map((c) => (c.secondary ? [c.main.id, c.secondary.id] : [c.main.id]));
+
+const indices = (chunks: Chunk[]) => chunks.map((c) => c.index);
+
+test('partitions single layout', () => {
+	const [chunks, lookup] = partition(pages, Layout.Single);
+
+	expect(ids(chunks)).toStrictEqual([[0], [1], [2], [3], [4], [5], [6]]);
+	expect(indices(chunks)).toStrictEqual([0, 1, 2, 3, 4, 5, 6]);
+	expect(lookup).toStrictEqual([0, 1, 2, 3, 4, 5, 6]);
+});
+
+test('partitions double layout', () => {
+	const [chunks, lookup] = partition(pages, Layout.Double);
+
+	expect(ids(chunks)).toStrictEqual([[0, 1], [2, 3], [4], [5, 6]]);
+	expect(indices(chunks)).toStrictEqual([0, 2, 4, 5]);
+	expect(lookup).toStrictEqual([0, 0, 1, 1, 2, 3, 3]);
+});
+
+test('partitions double (offset) layout', () => {
+	const [chunks, lookup] = partition(pages, Layout.DoubleOffset);
+
+	expect(ids(chunks)).toStrictEqual([[0], [1, 2], [3], [4], [5, 6]]);
+	expect(indices(chunks)).toStrictEqual([0, 1, 3, 4, 5]);
+	expect(lookup).toStrictEqual([0, 1, 1, 2, 3, 4, 4]);
+});