add nova

nova/resources/js/__tests__/util/increaseOrDecrease.test.js

@@ -0,0 +1,17 @@
+import increaseOrDecrease from '@/util/increaseOrDecrease'
+
+test('it can calculate increase in percentage', () => {
+  expect(increaseOrDecrease(50, 0)).toBe(null)
+  expect(increaseOrDecrease(45, 10)).toBe(350)
+  expect(increaseOrDecrease(45, 36)).toBe(25)
+  expect(increaseOrDecrease(45, 40)).toBe(12.5)
+  expect(increaseOrDecrease(50, -50)).toBe(200)
+})
+
+test('it can calculate decrease in percentage', () => {
+  expect(increaseOrDecrease(0, 50)).toBe(-100)
+  expect(increaseOrDecrease(10, 45)).toBe(-77.77777777777779)
+  expect(increaseOrDecrease(36, 45)).toBe(-20)
+  expect(increaseOrDecrease(40, 45)).toBe(-11.11111111111111)
+  expect(increaseOrDecrease(-50, 50)).toBe(-200)
+})