[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/getters.spec.js

@@ -0,0 +1,56 @@
+import { getters } from '../../conversation';
+
+describe('#getters', () => {
+  it('getConversation', () => {
+    const state = {
+      conversations: {
+        1: {
+          content: 'hello',
+        },
+      },
+    };
+    expect(getters.getConversation(state)).toEqual({
+      1: {
+        content: 'hello',
+      },
+    });
+  });
+
+  it('getConversationSize', () => {
+    const state = {
+      conversations: {
+        1: {
+          content: 'hello',
+        },
+      },
+    };
+    expect(getters.getConversationSize(state)).toEqual(1);
+  });
+
+  it('getEarliestMessage', () => {
+    const state = {
+      conversations: {
+        1: {
+          content: 'hello',
+        },
+        2: {
+          content: 'hello1',
+        },
+      },
+    };
+    expect(getters.getEarliestMessage(state)).toEqual({
+      content: 'hello',
+    });
+  });
+
+  it('uiFlags', () => {
+    const state = {
+      uiFlags: {
+        allMessagesLoaded: false,
+        isFetchingList: false,
+      },
+    };
+    expect(getters.getAllMessagesLoaded(state)).toEqual(false);
+    expect(getters.getIsFetchingList(state)).toEqual(false);
+  });
+});