Add test for OffsetCursorPaginator

Author: sgarner

src/cursor/OffsetCursorPaginator.spec.ts

@@ -0,0 +1,54 @@
+import { OffsetCursor, OffsetCursorPaginator } from './OffsetCursorPaginator';
+
+describe('OffsetCursorPaginator', () => {
+  test('PageInfo is correct for first page', () => {
+    const paginator = new OffsetCursorPaginator({
+      take: 20,
+      skip: 0,
+      totalEdges: 50,
+    });
+    const pageInfo = paginator.createPageInfo(20);
+
+    expect(pageInfo.totalEdges).toBe(50);
+    expect(pageInfo.hasPreviousPage).toBe(false);
+    expect(pageInfo.hasNextPage).toBe(true);
+    expect(pageInfo.startCursor).toBeDefined();
+    expect(OffsetCursor.create(pageInfo.startCursor!).parameters.offset).toStrictEqual(0);
+    expect(pageInfo.endCursor).toBeDefined();
+    expect(OffsetCursor.create(pageInfo.endCursor!).parameters.offset).toStrictEqual(19);
+  });
+
+  test('PageInfo is correct for second page', () => {
+    const paginator = new OffsetCursorPaginator({
+      take: 20,
+      skip: 20,
+      totalEdges: 50,
+    });
+    const pageInfo = paginator.createPageInfo(20);
+
+    expect(pageInfo.totalEdges).toBe(50);
+    expect(pageInfo.hasPreviousPage).toBe(true);
+    expect(pageInfo.hasNextPage).toBe(true);
+    expect(pageInfo.startCursor).toBeDefined();
+    expect(OffsetCursor.create(pageInfo.startCursor!).parameters.offset).toStrictEqual(20);
+    expect(pageInfo.endCursor).toBeDefined();
+    expect(OffsetCursor.create(pageInfo.endCursor!).parameters.offset).toStrictEqual(39);
+  });
+
+  test('PageInfo is correct for last page', () => {
+    const paginator = new OffsetCursorPaginator({
+      take: 20,
+      skip: 40,
+      totalEdges: 50,
+    });
+    const pageInfo = paginator.createPageInfo(10);
+
+    expect(pageInfo.totalEdges).toBe(50);
+    expect(pageInfo.hasPreviousPage).toBe(true);
+    expect(pageInfo.hasNextPage).toBe(false);
+    expect(pageInfo.startCursor).toBeDefined();
+    expect(OffsetCursor.create(pageInfo.startCursor!).parameters.offset).toStrictEqual(40);
+    expect(pageInfo.endCursor).toBeDefined();
+    expect(OffsetCursor.create(pageInfo.endCursor!).parameters.offset).toStrictEqual(49);
+  });
+});