Add tests for Registration component

app/soapbox/features/verification/__tests__/registration.test.js

@@ -0,0 +1,67 @@
+import React from 'react';
+
+import { __stub } from 'soapbox/api';
+
+import { fireEvent, render, screen, waitFor } from '../../../jest/test-helpers';
+import Registration from '../registration';
+
+describe('<Registration />', () => {
+  it('renders', () => {
+    render(<Registration />);
+
+    expect(screen.getByRole('heading')).toHaveTextContent(/register your account/i);
+  });
+
+  describe('with valid data', () => {
+    beforeEach(() => {
+      __stub(mock => {
+        mock.onPost('/api/v1/pepe/accounts').reply(200, {});
+        mock.onPost('/api/v1/apps').reply(200, {});
+        mock.onPost('/oauth/token').reply(200, {});
+        mock.onPost('/api/v1/accounts/verify_credentials').reply(200, {});
+        mock.onGet('/api/v1/instance').reply(200, {});
+      });
+    });
+
+    it('handles successful submission', async() => {
+      render(<Registration />);
+
+      await waitFor(() => {
+        fireEvent.submit(screen.getByTestId('button'), { preventDefault: () => {} });
+      });
+
+      expect(screen.getByTestId('toast')).toHaveTextContent(/welcome to/i);
+      expect(screen.queryAllByRole('heading')).toHaveLength(0);
+    });
+  });
+
+  describe('with invalid data', () => {
+    it('handles 422 errors', async() => {
+      __stub(mock => {
+        mock.onPost('/api/v1/pepe/accounts').reply(422, {});
+      });
+
+      render(<Registration />);
+
+      await waitFor(() => {
+        fireEvent.submit(screen.getByTestId('button'), { preventDefault: () => {} });
+      });
+
+      expect(screen.getByTestId('toast')).toHaveTextContent(/this username has already been taken/i);
+    });
+
+    it('handles generic errors', async() => {
+      __stub(mock => {
+        mock.onPost('/api/v1/pepe/accounts').reply(500, {});
+      });
+
+      render(<Registration />);
+
+      await waitFor(() => {
+        fireEvent.submit(screen.getByTestId('button'), { preventDefault: () => {} });
+      });
+
+      expect(screen.getByTestId('toast')).toHaveTextContent(/failed to register your account/i);
+    });
+  });
+});