v1.0 with SW PWA enabled

frontend/node_modules/react-day-picker/src/contexts/Navigation/utils/getPreviousMonth.test.ts

@@ -0,0 +1,55 @@
+import { addMonths, isSameMonth } from 'date-fns';
+
+import { getPreviousMonth } from './getPreviousMonth';
+
+const startingMonth = new Date(2020, 4, 31);
+
+describe('when number of months is 1', () => {
+  describe('when the navigation is disabled', () => {
+    const disableNavigation = true;
+    it('the previous month is undefined', () => {
+      const result = getPreviousMonth(startingMonth, { disableNavigation });
+      expect(result).toBe(undefined);
+    });
+  });
+  describe('when in the navigable range', () => {
+    const fromDate = addMonths(startingMonth, -3);
+    it('the previous month is not undefined', () => {
+      const result = getPreviousMonth(startingMonth, { fromDate });
+      const expectedPrevMonth = addMonths(startingMonth, -1);
+      expect(result && isSameMonth(result, expectedPrevMonth)).toBeTruthy();
+    });
+  });
+  describe('when not in the navigable range', () => {
+    const fromDate = startingMonth;
+    it('the previous month is undefined', () => {
+      const result = getPreviousMonth(startingMonth, { fromDate });
+      expect(result).toBe(undefined);
+    });
+  });
+});
+describe('when displaying 3 months', () => {
+  const numberOfMonths = 3;
+  describe('when the navigation is paged', () => {
+    const pagedNavigation = true;
+    it('the previous month is 3 months back', () => {
+      const result = getPreviousMonth(startingMonth, {
+        numberOfMonths,
+        pagedNavigation
+      });
+      const expectedPrevMonth = addMonths(startingMonth, -numberOfMonths);
+      expect(result && isSameMonth(result, expectedPrevMonth)).toBeTruthy();
+    });
+  });
+  describe('when the navigation is not paged', () => {
+    const pagedNavigation = false;
+    it('the previous month is 1 months back', () => {
+      const result = getPreviousMonth(startingMonth, {
+        numberOfMonths,
+        pagedNavigation
+      });
+      const expectedPrevMonth = addMonths(startingMonth, -1);
+      expect(result && isSameMonth(result, expectedPrevMonth)).toBeTruthy();
+    });
+  });
+});