[canvas] migrate tests away from karma (#73121)

Co-authored-by: spalger <spalger@users.noreply.github.com>
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>

x-pack/plugins/canvas/public/components/loading/loading.test.tsx

@@ -0,0 +1,36 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import React from 'react';
+import { shallow } from 'enzyme';
+import { Loading } from './loading';
+
+describe('<Loading />', () => {
+  it('uses EuiIcon by default', () => {
+    expect(shallow(<Loading />)).toMatchInlineSnapshot(`
+      <div
+        className="canvasLoading"
+      >
+        <EuiIcon
+          color="ghost"
+          type="clock"
+        />
+      </div>
+    `);
+  });
+
+  it('uses EuiLoadingSpinner when animating', () => {
+    expect(shallow(<Loading animated />)).toMatchInlineSnapshot(`
+      <div
+        className="canvasLoading"
+      >
+        <EuiLoadingSpinner
+          size="m"
+        />
+      </div>
+    `);
+  });
+});