Add pagination helper tests (#970)

internal/test/unit/pagination.test.js

@@ -0,0 +1,74 @@
+import React from 'react'
+import { 
+  pageInputWidth, 
+  pagesFromItems, 
+  changePageIfAppropiate, 
+  totals,
+  getPaginationSlice
+} from '@auth0/cosmos/_helpers/pagination'
+
+describe('Pagination helper tests', () => {
+
+  it('should calculate page input width', () => {
+    expect(pageInputWidth(1)).toEqual(58)
+    expect(pageInputWidth(10)).toEqual(66)
+    expect(pageInputWidth(100)).toEqual(74)
+    expect(pageInputWidth(1000)).toEqual(82)
+  })
+
+  it('should calculate pagesFromItems', () => {
+    expect(pagesFromItems(100,10)).toEqual(10)
+    expect(pagesFromItems(104,10)).toEqual(11)
+    expect(pagesFromItems(1,10)).toEqual(1)
+    expect(pagesFromItems(0,10)).toEqual(0)
+  })
+
+  it('should call change page handlers on last edge when appropiate', () => {
+    const changePageHandler = jest.fn()
+
+    let nextPage = 121
+    const totalItems = 1200
+    const perPage = 10
+    changePageIfAppropiate(nextPage, totalItems, perPage, changePageHandler)
+    expect(changePageHandler).not.toHaveBeenCalled()
+
+    nextPage = 120
+    changePageIfAppropiate(nextPage, totalItems, perPage, changePageHandler)
+    expect(changePageHandler).toHaveBeenCalledWith(nextPage)
+  })
+
+  it('should call change page handlers on first edge when appropiate', () => {
+    const changePageHandler = jest.fn()
+
+    let nextPage = -1
+    const totalItems = 1200
+    const perPage = 10
+    changePageIfAppropiate(nextPage, totalItems, perPage, changePageHandler)
+    expect(changePageHandler).not.toHaveBeenCalled()
+
+    nextPage = 1
+    changePageIfAppropiate(nextPage, totalItems, perPage, changePageHandler)
+    expect(changePageHandler).toHaveBeenCalledWith(nextPage)
+  })
+
+  it('should display totals', () => {
+    expect(totals(75, 10, 12000)).toEqual("Showing 741 - 750 of 12000")
+    expect(totals(75, 13, 12345)).toEqual("Showing 963 - 975 of 12345")
+    expect(totals(1, 10, 54321)).toEqual("Showing 1 - 10 of 54321")
+    expect(totals(1200, 10, 12000)).toEqual("Showing 11991 - 12000 of 12000")
+  })
+
+  it('should generate pagination content', () => {
+    const prettify = (p) => p.map(i => i.selected ? `[${i.label}]` : i.label)
+
+    expect(prettify(getPaginationSlice(2, 100, 10, 10)))
+        .toEqual([1, '[2]', 3, 4, 5, 6, 7, 8, 9, 10])
+
+    expect(prettify(getPaginationSlice(99, 1000, 10, 10)))
+        .toEqual([91, 92, 93, 94, 95, 96, 97, 98, '[99]', 100])
+
+    expect(prettify(getPaginationSlice(93, 960, 10, 10)))
+        .toEqual([91, 92, '[93]', 94, 95, 96])
+  })
+})
+