Add tests.

x-pack/plugins/uptime/public/components/overview/monitor_list/__tests__/monitor_list.test.tsx

@@ -10,7 +10,7 @@ import {
   CursorDirection,
   SortOrder,
 } from '../../../../../common/runtime_types';
-import { MonitorListComponent } from '../monitor_list';
+import { MonitorListComponent, noItemsMessage } from '../monitor_list';
 import { renderWithRouter, shallowWithRouter } from '../../../../lib';
 import * as redux from 'react-redux';
 
@@ -288,4 +288,24 @@ describe('MonitorList component', () => {
       expect(component).toMatchSnapshot();
     });
   });
+
+  describe('noItemsMessage', () => {
+    it('returns loading message while loading', () => {
+      expect(noItemsMessage(true)).toEqual(`Loading...`);
+    });
+
+    it('returns loading message when filters are defined and loading', () => {
+      expect(noItemsMessage(true, 'filters')).toEqual(`Loading...`);
+    });
+
+    it('returns no monitors selected when filters are defined and not loading', () => {
+      expect(noItemsMessage(false, 'filters')).toEqual(
+        `No monitors found for selected filter criteria`
+      );
+    });
+
+    it('returns no data message when no filters and not loading', () => {
+      expect(noItemsMessage(false)).toEqual(`No uptime monitors found`);
+    });
+  });
 });

x-pack/plugins/uptime/public/components/overview/monitor_list/monitor_list.tsx

@@ -43,7 +43,7 @@ const TruncatedEuiLink = styled(EuiLink)`
   text-overflow: ellipsis;
 `;
 
-const noItemsMessage = (loading: boolean, filters?: string) => {
+export const noItemsMessage = (loading: boolean, filters?: string) => {
   if (loading) return labels.LOADING;
   return !!filters ? labels.NO_MONITOR_ITEM_SELECTED : labels.NO_DATA_MESSAGE;
 };