Add markdown parser to ErrorPanel (#39432)

* Add markdown parsing to PanelError for type string

* Add jest tests

* Remove obsolete test

src/legacy/core_plugins/kibana/public/dashboard/panel/__snapshots__/panel_error.test.tsx.snap

@@ -0,0 +1,96 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`PanelError renders given React Element  1`] = `
+<div
+  class="dshPanel__error panel-content"
+>
+  <div
+    class="euiText euiText--extraSmall"
+  >
+    <div
+      class="euiTextColor euiTextColor--subdued"
+    >
+      <svg
+        class="euiIcon euiIcon--medium euiIcon--danger euiIcon-isLoading"
+        focusable="false"
+        height="16"
+        viewBox="0 0 16 16"
+        width="16"
+        xmlns="http://www.w3.org/2000/svg"
+      />
+      <div
+        class="euiSpacer euiSpacer--s"
+      />
+      <div>
+        test
+      </div>
+    </div>
+  </div>
+</div>
+`;
+
+exports[`PanelError renders plain string 1`] = `
+<div
+  class="dshPanel__error panel-content"
+>
+  <div
+    class="euiText euiText--extraSmall"
+  >
+    <div
+      class="euiTextColor euiTextColor--subdued"
+    >
+      <svg
+        class="euiIcon euiIcon--medium euiIcon--danger euiIcon-isLoading"
+        focusable="false"
+        height="16"
+        viewBox="0 0 16 16"
+        width="16"
+        xmlns="http://www.w3.org/2000/svg"
+      />
+      <div
+        class="euiSpacer euiSpacer--s"
+      />
+      <div>
+        <p>
+          test
+        </p>
+      </div>
+    </div>
+  </div>
+</div>
+`;
+
+exports[`PanelError renders string with markdown link 1`] = `
+<div
+  class="dshPanel__error panel-content"
+>
+  <div
+    class="euiText euiText--extraSmall"
+  >
+    <div
+      class="euiTextColor euiTextColor--subdued"
+    >
+      <svg
+        class="euiIcon euiIcon--medium euiIcon--danger euiIcon-isLoading"
+        focusable="false"
+        height="16"
+        viewBox="0 0 16 16"
+        width="16"
+        xmlns="http://www.w3.org/2000/svg"
+      />
+      <div
+        class="euiSpacer euiSpacer--s"
+      />
+      <div>
+        <p>
+          <a
+            href="http://www.elastic.co/"
+          >
+            test
+          </a>
+        </p>
+      </div>
+    </div>
+  </div>
+</div>
+`;

src/legacy/core_plugins/kibana/public/dashboard/panel/panel_error.test.tsx

@@ -0,0 +1,40 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+// TODO: remove this when EUI supports types for this.
+// @ts-ignore: implicit any for JS file
+import { takeMountedSnapshot } from '@elastic/eui/lib/test';
+import React from 'react';
+import { PanelError } from './panel_error';
+import { mount } from 'enzyme';
+
+test('PanelError renders plain string', () => {
+  const component = mount(<PanelError error="test" />);
+  expect(takeMountedSnapshot(component)).toMatchSnapshot();
+});
+
+test('PanelError renders string with markdown link', () => {
+  const component = mount(<PanelError error="[test](http://www.elastic.co/)" />);
+  expect(takeMountedSnapshot(component)).toMatchSnapshot();
+});
+
+test('PanelError renders given React Element ', () => {
+  const component = mount(<PanelError error={<div>test</div>} />);
+  expect(takeMountedSnapshot(component)).toMatchSnapshot();
+});

src/legacy/core_plugins/kibana/public/dashboard/panel/panel_error.tsx

@@ -18,6 +18,7 @@
  */
 
 import { EuiIcon, EuiSpacer, EuiText } from '@elastic/eui';
+import ReactMarkdown from 'react-markdown';
 import React from 'react';
 
 export interface PanelErrorProps {
@@ -30,7 +31,7 @@ export function PanelError({ error }: PanelErrorProps) {
       <EuiText color="subdued" size="xs">
         <EuiIcon type="alert" color="danger" />
         <EuiSpacer size="s" />
-        {error}
+        {typeof error === 'string' ? <ReactMarkdown source={error} /> : error}
       </EuiText>
     </div>
   );