Try to implement test round abount empApi.

fs-core/main/default/lwc/formulaShareRulesListView/__tests__/data/prefix.json

@@ -0,0 +1 @@
+""

fs-core/main/default/lwc/formulaShareRulesListView/__tests__/formulaShareRulesListViewEmpApi.test.js

@@ -0,0 +1,60 @@
+import { createElement } from 'lwc';
+import FormulaShareRulesListView from 'c/formulaShareRulesListView';
+import { registerLdsTestWireAdapter } from '@salesforce/sfdx-lwc-jest';
+import { getTreeGridData } from '@salesforce/apex/FormulaShareRulesListViewController.getTreeGridData';
+import getNamespacePrefix from '@salesforce/apex/FormulaShareUtilities.getNamespacePrefix';
+
+import { jestMockPublish } from 'lightning/empApi';
+
+// Register a test wire adapter.
+const getTreeGridDataWireAdapter = registerLdsTestWireAdapter(getTreeGridData);
+const getPrefixWireAdapter = registerLdsTestWireAdapter(getNamespacePrefix);
+
+// Import mock data to send through the wire adapter.
+const mockExampleTreeGridData = require('./data/exampleTreeGridData.json');
+const mockPrefixData = require('./data/prefix.json');
+
+// eslint-disable-next-line no-undef
+const flushPromises = () => new Promise(setImmediate);
+
+describe('c-formula-share-rules-list-view', () => {
+    afterEach(() => {
+        // The jsdom instance is shared across test cases in a single file so reset the DOM
+        while (document.body.firstChild) {
+            document.body.removeChild(document.body.firstChild);
+        }
+
+        // Prevent data saved on mocks from leaking between tests
+        jest.clearAllMocks();
+    });
+
+    it('Test activate events (Positive).', async () => {
+        // Create initial lwc element and attach to virtual DOM.
+        const element = createElement('c-formula-share-rules-list-view', {
+            is: FormulaShareRulesListView
+        });
+        document.body.appendChild(element);
+
+        getPrefixWireAdapter.emit(mockPrefixData);
+        getTreeGridDataWireAdapter.emit(mockExampleTreeGridData);
+
+        // Make sure async subscribe call in connectedCallback completes
+        await flushPromises();
+
+        // connectedCallback is now complete, but no Platform Events have 
+        // been published yet.  Make assertions here about the state of your 
+        // component prior to receiving the Platform Events.
+
+        // Mock-publish a Platform Event and await the promise
+        await jestMockPublish('/event/FormulaShare_List_Update__e', {
+            data: {
+                payload: {
+                    Object_Label__c: 'Account',
+                    Type__c: 'activate'
+                }
+            }
+        });
+        // Now any DOM updates that depend on the Platform Event should 
+        // have rendered; assert about them here.
+    });
+});

fs-core/main/default/lwc/formulaShareRulesListView/formulaShareRulesListView.js

@@ -7,6 +7,7 @@ import getTreeGridData from '@salesforce/apex/FormulaShareRulesListViewControlle
 import recalculateSharing from '@salesforce/apex/FormulaShareRulesListViewController.recalculateSharing';
 import activateDeactivate from '@salesforce/apex/FormulaShareRulesListViewController.activateDeactivate';
 import getNamespacePrefix from '@salesforce/apex/FormulaShareUtilities.getNamespacePrefix';
+import isContactSharingControlledByAccount from '@salesforce/apex/FormulaShareUtilities.isContactSharingControlledByAccount';
 
 
 export default class TreeGrid extends NavigationMixin(LightningElement) {
@@ -142,7 +143,7 @@ export default class TreeGrid extends NavigationMixin(LightningElement) {
         }
 
         else if(error) {
-            //console.log('Error fetching data from Salesforce');
+            console.log('Error fetching data from Salesforce');
             this.showError(error, 'Error fetching data from Salesforce');
         }
     }
@@ -187,43 +188,70 @@ export default class TreeGrid extends NavigationMixin(LightningElement) {
         }
     }
 
+    prefix;
+    @wire(getNamespacePrefix)
+    wiredNamespacePrefix({ error, data })
+    {
+        if (data) {
+            console.log('>>>data: ' + JSON.stringify(data, null, '\t'));
+
+            this.prefix = data;
+        } else if (error) {
+            console.error('>>>error: ' + error);
+            this.prefix = undefined;
+            console.log('Error getting namespace prefix');
+            this.showError(error, 'Error getting namespace prefix');
+        }        
+    }
 
     // Subcribes to list platform event, and refresh treegrid each time event is received
     createOrUpdate = false;
     manageRefreshEvents() {
+        console.log('>>>manageRefreshEvents.');
 
         // Get namespace prefix
-        getNamespacePrefix()
-            .then((prefix) => {
-                //console.log('Got namespace: '+prefix);
+        /*getNamespacePrefix()
+            .then((prefix) => {*/
+                try {
+                    console.log('Got namespace: '+ JSON.stringify(this.prefix, null, '\t'));
 
                 // Subscribe to list update events (raised by batch job and on rule activate/deactivate)
                 const listUpdateCallback = (response) => {
-                    //console.log('Received Refresh Event');
+                    console.log('Received Refresh Event');
                     this.refreshView();
                 };
-                subscribe('/event/'+prefix+'FormulaShare_List_Update__e', -1, listUpdateCallback).then(response => {
-                    //console.log('Successfully subscribed to : ', JSON.stringify(response.channel));
+                console.log('#1');
+                subscribe('/event/'+this.prefix+'FormulaShare_List_Update__e', -1, listUpdateCallback)
+                .then(response => {
+                    console.log('Successfully subscribed to : ', JSON.stringify(response.channel));
+                })
+                .catch(error => {
+                    console.error('>>>error 2: ', JSON.stringify(error));
                 });
-
+                console.log('#2');
                 // Scubscribe to dml events (raised by on rule create/edit)
                 const dmlUpdateCallback = (response) => {
                     if(response.data.payload.Successful__c || response.data.payload.sdfs__Successful__c) {
-                        //console.log('Received FormulaShare_Rule_DML__e');
+                        console.log('Received FormulaShare_Rule_DML__e');
                         this.createOrUpdate = true;
                         this.refreshView();
                     }
                 };
+                console.log('#3');
                 subscribe('/event/'+prefix+'FormulaShare_Rule_DML__e', -1, dmlUpdateCallback).then(response => {
-                    //console.log('List component subscribed to : ', JSON.stringify(response.channel));
+                    console.log('List component subscribed to : ', JSON.stringify(response.channel));
                 });
-
-            })
-            .catch(error => {
-                //console.log('Error getting namespace prefix');
+                console.log('#4');
+                } catch (error) {
+                    console.error('>>>error: ', JSON.stringify(error));
+                }
+
+            }
+            /*.catch(error => {
+                console.log('Error getting namespace prefix');
                 this.showError(error, 'Error getting namespace prefix');
             });
-    }
+    }*/
 
 
     // Set available drop-down actions for each grid row
@@ -376,19 +404,25 @@ export default class TreeGrid extends NavigationMixin(LightningElement) {
     // Action method to update a rule to active/inactive
     spinnerClasses;
     activateDeactivate(row, actionName) {
+        console.log('>>>activateDeactivate.');
+        console.log('>>>row: ' + JSON.stringify(row, null, '\t'));
+        console.log('>>>actionName: ' + JSON.stringify(actionName, null, '\t'));
+
         const rowDeveloperName = row['developerName'];
         activateDeactivate({ ruleName : rowDeveloperName, type : actionName })
             .then(() => {
+                console.log('then()');
                 this.processingLoad = true;
                 this.spinnerClasses = 'processingMessage';
 
                 // After submitting, wait 5 seconds and add class to display 
                 setTimeout(() => {
                     this.spinnerClasses = 'processingMessage afterProcessingMessage';
                 }, 5000);
+                console.log('#1')
             })
             .catch(error => {
-                //console.log('Error changing activation status');
+                console.log('Error changing activation status');
                 this.showError(error, 'Error changing activation status')
             });
     }
@@ -423,6 +457,9 @@ export default class TreeGrid extends NavigationMixin(LightningElement) {
 
     // Called to trigger a toast message including a system error
     showError(error, toastTitle) {
+        console.log('>>>error: ' + JSON.stringify(error, null, '\t'));
+        console.log('>>>toastTitle: ' + JSON.stringify(toastTitle, null, '\t'));
+
         let errorMessage = 'Unknown error';
         if (Array.isArray(error.body)) {
             errorMessage = error.body.map(e => e.message).join(', ');

fs-core/test/jest-mocks/lightning/empApi.js

@@ -0,0 +1,33 @@
+
+// https://salesforce.stackexchange.com/questions/297563/test-lightning-emp-api
+// An object to store callbacks
+const _channels = {};
+
+// On subscribe, store the callback function and resolve the promise
+export const subscribe = jest.fn((channel, replayId, onMessageCallback) => {
+    _channels[channel] = { onMessageCallback };
+    Promise.resolve({
+        id: "_" + Date.now(),
+        channel: channel,
+        replayId: replayId
+    });
+});
+
+// I'm using isEmpEnabled in my component, so I have it set to return true
+export const isEmpEnabled = jest.fn().mockResolvedValue(true);
+
+// A Jest-specific function for "publishing" your Platform Event
+export const jestMockPublish = jest.fn((channel, message) => {
+    if (
+        _channels[channel] &&
+        _channels[channel].onMessageCallback instanceof Function
+    ) {
+        _channels[channel].onMessageCallback(message);
+    }
+    Promise.resolve(true);
+});
+
+// I just copied these from the standard lightning/empApi stub
+export const unsubscribe = jest.fn().mockResolvedValue({});
+export const onError = jest.fn().mockResolvedValue(jest.fn());
+export const setDebugFlag = jest.fn().mockResolvedValue();

jest.config.js

@@ -13,7 +13,9 @@ module.exports = {
         '^lightning/uiRecordApi$':
             '<rootDir>/fs-core/test/jest-mocks/lightning/uiRecordApi',
         '^lightning/messageService$':
-            '<rootDir>/fs-core/test/jest-mocks/lightning/messageService'
+            '<rootDir>/fs-core/test/jest-mocks/lightning/messageService',
+        "^lightning/empApi$":
+            "<rootDir>/fs-core/test/jest-mocks/lightning/empApi"
     },
     //setupFiles: ['jest-canvas-mock'],
     setupFilesAfterEnv,