Refactored ServerError to infer error message based on provided server type guards

test/servers/helpers/ServerError.test.tsx

@@ -0,0 +1,50 @@
+import React from 'react';
+import { shallow, ShallowWrapper } from 'enzyme';
+import { BrowserRouter } from 'react-router-dom';
+import { Mock } from 'ts-mockery';
+import { ServerError as createServerError } from '../../../src/servers/helpers/ServerError';
+import { NonReachableServer, NotFoundServer } from '../../../src/servers/data';
+
+describe('<ServerError />', () => {
+  let wrapper: ShallowWrapper;
+  const ServerError = createServerError(() => null);
+
+  afterEach(() => wrapper?.unmount());
+
+  it.each([
+    [
+      Mock.all<NotFoundServer>(),
+      {
+        'Could not find this Shlink server.': true,
+        'Oops! Could not connect to this Shlink server.': false,
+        'Make sure you have internet connection, and the server is properly configured and on-line.': false,
+        'Alternatively, if you think you may have miss-configured this server': false,
+      },
+    ],
+    [
+      Mock.of<NonReachableServer>({ id: 'abc123' }),
+      {
+        'Could not find this Shlink server.': false,
+        'Oops! Could not connect to this Shlink server.': true,
+        'Make sure you have internet connection, and the server is properly configured and on-line.': true,
+        'Alternatively, if you think you may have miss-configured this server': true,
+      },
+    ],
+  ])('renders expected information based on provided server type', (selectedServer, textsToFind) => {
+    wrapper = shallow(
+      <BrowserRouter>
+        <ServerError servers={{}} selectedServer={selectedServer} />
+      </BrowserRouter>,
+    );
+    const wrapperText = wrapper.html();
+    const textPairs = Object.entries(textsToFind);
+
+    textPairs.forEach(([ text, shouldBeFound ]) => {
+      if (shouldBeFound) {
+        expect(wrapperText).toContain(text);
+      } else {
+        expect(wrapperText).not.toContain(text);
+      }
+    });
+  });
+});