[Enhancement] Fetch previous messages in the conversation (#355)

* Fetch previous messages in the conversation

* Add specs for conversation store

* Fix codeclimate issues

* Exclude specs folder

* Exclude globally

* Fix path in exclude patterns

* Add endPoints spec

* Add snapshots for Spinner

* Add specs for actions

app/javascript/widget/store/modules/specs/conversation/utils.spec.js

@@ -0,0 +1,37 @@
+import {
+  findUndeliveredMessage,
+  createTemporaryMessage,
+} from '../../conversation';
+
+describe('#findUndeliveredMessage', () => {
+  it('returns message objects if exist', () => {
+    const conversation = {
+      1: {
+        id: 1,
+        content: 'Hello',
+        status: 'in_progress',
+      },
+      2: {
+        id: 2,
+        content: 'Hello',
+        status: 'sent',
+      },
+      3: {
+        id: 3,
+        content: 'How may I help you',
+        status: 'sent',
+      },
+    };
+    expect(
+      findUndeliveredMessage(conversation, { content: 'Hello' })
+    ).toStrictEqual([{ id: 1, content: 'Hello', status: 'in_progress' }]);
+  });
+});
+
+describe('#createTemporaryMessage', () => {
+  it('returns message object', () => {
+    const message = createTemporaryMessage('hello');
+    expect(message.content).toBe('hello');
+    expect(message.status).toBe('in_progress');
+  });
+});