Fix the browser back button in Open MCT (#3526)

Fixes Open MCT back button.

Co-authored-by: Joshi <simplyrender@gmail.com>

src/ui/router/ApplicationRouterSpec.js

@@ -0,0 +1,139 @@
+import { createOpenMct, resetApplicationState } from 'utils/testing';
+
+let openmct;
+let element;
+let child;
+let appHolder;
+let resolveFunction;
+
+let initialHash = '';
+
+describe('Application router utility functions', () => {
+    beforeAll(done => {
+        appHolder = document.createElement('div');
+        appHolder.style.width = '640px';
+        appHolder.style.height = '480px';
+
+        openmct = createOpenMct();
+        openmct.install(openmct.plugins.MyItems());
+        openmct.install(openmct.plugins.LocalTimeSystem());
+        openmct.install(openmct.plugins.UTCTimeSystem());
+
+        element = document.createElement('div');
+        child = document.createElement('div');
+        element.appendChild(child);
+
+        openmct.on('start', done);
+        openmct.start(appHolder);
+
+        document.body.append(appHolder);
+    });
+
+    afterAll(() => {
+        openmct.router.setHash(initialHash);
+        appHolder.remove();
+
+        return resetApplicationState(openmct);
+    });
+
+    it('has initial hash when loaded', (done) => {
+        let success;
+        resolveFunction = () => {
+            openmct.router.setLocationFromUrl();
+            success = window.location.hash !== null;
+            if (success) {
+                initialHash = window.location.hash;
+                expect(success).toBe(true);
+
+                openmct.router.removeListener('change:hash', resolveFunction);
+                done();
+            }
+        };
+
+        openmct.router.on('change:hash', resolveFunction);
+    });
+
+    it('The setSearchParam function sets an individual search parameter in the window location hash', (done) => {
+        let success;
+        openmct.router.setSearchParam('testParam', 'testValue');
+        resolveFunction = () => {
+            success = window.location.hash.includes('testParam=testValue');
+            if (success) {
+                expect(success).toBe(true);
+
+                openmct.router.removeListener('change:hash', resolveFunction);
+                done();
+            }
+        };
+
+        openmct.router.on('change:hash', resolveFunction);
+    });
+
+    it('The getSearchParam function returns the value of an individual search paramater in the window location hash', () => {
+        expect(openmct.router.getSearchParam('testParam')).toBe('testValue');
+    });
+
+    it('The deleteSearchParam function deletes an individual search paramater in the window location hash', (done) => {
+        let success;
+        openmct.router.deleteSearchParam('testParam');
+        resolveFunction = () => {
+            success = window.location.hash.includes('testParam=testValue') === false;
+            if (success) {
+                expect(success).toBe(true);
+
+                openmct.router.removeListener('change:hash', resolveFunction);
+                done();
+            }
+        };
+
+        openmct.router.on('change:hash', resolveFunction);
+    });
+
+    it('The setSearchParam function sets an individual search parameters in the window location hash', (done) => {
+        let success;
+        openmct.router.setSearchParam('testParam1', 'testValue1');
+        openmct.router.setSearchParam('testParam2', 'testValue2');
+
+        resolveFunction = () => {
+            const hasTestParam1 = window.location.hash.includes('testParam1=testValue1');
+            const hasTestParam2 = window.location.hash.includes('testParam2=testValue2');
+            success = hasTestParam1 && hasTestParam2;
+            if (success) {
+                expect(success).toBe(true);
+
+                openmct.router.removeListener('change:hash', resolveFunction);
+                done();
+            }
+        };
+
+        openmct.router.on('change:hash', resolveFunction);
+    });
+
+    it('The setAllSearchParams function replaces all search paramaters in the window location hash', (done) => {
+        let success;
+
+        openmct.router.setSearchParam('testParam2', 'updatedtestValue2');
+        openmct.router.setSearchParam('newTestParam3', 'newTestValue3');
+
+        resolveFunction = () => {
+            const hasupdatedValueForTestParam2 = window.location.hash.includes('testParam2=updatedtestValue2');
+            const hasNewTestParam3 = window.location.hash.includes('newTestParam3=newTestValue3');
+            success = hasupdatedValueForTestParam2 && hasNewTestParam3;
+            if (success) {
+                expect(success).toBe(true);
+
+                openmct.router.removeListener('change:hash', resolveFunction);
+                done();
+            }
+        };
+
+        openmct.router.on('change:hash', resolveFunction);
+    });
+
+    it('The getAllSearchParams function returns the values of all search paramaters in the window location hash', () => {
+        let searchParams = openmct.router.getAllSearchParams();
+        expect(searchParams.get('testParam1')).toBe('testValue1');
+        expect(searchParams.get('testParam2')).toBe('updatedtestValue2');
+        expect(searchParams.get('newTestParam3')).toBe('newTestValue3');
+    });
+});