add initial tests

frontend/test/pulse/pulse.unit.spec.js

+import React from 'react'
+import { shallow } from 'enzyme'
+
+import UserAvatar from 'metabase/components/UserAvatar'
+import RecipientPicker from 'metabase/pulse/components/RecipientPicker'
+
+// We have to do some mocking here to avoid calls to GA and to Metabase settings
+jest.mock('metabase/lib/settings', () => ({
+    get: () => 'v'
+}))
+
+global.ga = jest.fn()
+
+const TEST_USERS = [
+    { id: 1, common_name: 'Barb', email: 'barb_holland@hawkins.mail' }, // w
+    { id: 2, common_name: 'Dustin', email: 'dustin_henderson@hawkinsav.club' }, // w
+    { id: 3, common_name: 'El', email: '011@energy.gov' },
+    { id: 4, common_name: 'Lucas', email: 'lucas.sinclair@hawkins.mail' }, // w
+    { id: 5, common_name: 'Mike', email: 'dm_mike@hawkins.mail' }, // w
+    { id: 6, common_name: 'Nancy', email: '' },
+    { id: 7, common_name: 'Steve', email: '' },
+    { id: 8, common_name: 'Will', email: 'zombieboy@upside.down' }, // w
+]
+
+describe('recipient picker', () => {
+        describe('filtering', () => {
+            it('should properly filter users based on input', () => {
+                const wrapper = shallow(
+                    <RecipientPicker
+                        recipients={[]}
+                        users={TEST_USERS}
+                        isNewPulse={true}
+                        onRecipientsChange={() => alert('why?')}
+                    />
+                )
+
+                const spy = jest.spyOn(wrapper.instance(), 'setInputValue')
+                const input = wrapper.find('input')
+
+                // we should start off with no users
+                expect(wrapper.state().filteredUsers.length).toBe(0)
+
+                // simulate typing 'w'
+                input.simulate('change', { target: { value: 'w' }})
+
+                expect(spy).toHaveBeenCalled()
+                expect(wrapper.state().inputValue).toEqual('w')
+
+                // 5 of the test users have a w in their name or email
+                expect(wrapper.state().filteredUsers.length).toBe(5)
+            })
+        })
+
+        describe('recipient selection', () => {
+            it('should allow the user to click to select a recipient', () => {
+                const spy = jest.fn()
+                const wrapper = shallow(
+                    <RecipientPicker
+                        recipients={[]}
+                        users={TEST_USERS}
+                        isNewPulse={true}
+                        onRecipientsChange={spy}
+                    />
+                )
+
+                const input = wrapper.find('input')
+                input.simulate('change', { target: { value: 'steve' }})
+
+                expect(wrapper.state().filteredUsers.length).toBe(1)
+
+                const user = wrapper.find(UserAvatar).closest('li')
+                user.simulate('click', { target: {}})
+
+                expect(spy).toHaveBeenCalled()
+            })
+        })
+})