3 files changed, 99 insertions, 8 deletions

diff --git a/spec/frontend/notes/components/discussion_counter_spec.js b/spec/frontend/notes/components/discussion_counter_spec.js
index 9db0f823d84..c454d502beb 100644
--- a/spec/frontend/notes/components/discussion_counter_spec.js
+++ b/spec/frontend/notes/components/discussion_counter_spec.js
@@ -53,7 +53,7 @@ describe('DiscussionCounter component', () => {
 
   describe('has no resolvable discussions', () => {
     it('does not render', () => {
-      store.commit(types.SET_INITIAL_DISCUSSIONS, [{ ...discussionMock, resolvable: false }]);
+      store.commit(types.ADD_OR_UPDATE_DISCUSSIONS, [{ ...discussionMock, resolvable: false }]);
       store.dispatch('updateResolvableDiscussionsCounts');
       wrapper = shallowMount(DiscussionCounter, { store, localVue });
 
@@ -64,7 +64,7 @@ describe('DiscussionCounter component', () => {
   describe('has resolvable discussions', () => {
     const updateStore = (note = {}) => {
       discussionMock.notes[0] = { ...discussionMock.notes[0], ...note };
-      store.commit(types.SET_INITIAL_DISCUSSIONS, [discussionMock]);
+      store.commit(types.ADD_OR_UPDATE_DISCUSSIONS, [discussionMock]);
       store.dispatch('updateResolvableDiscussionsCounts');
     };
 
@@ -97,7 +97,7 @@ describe('DiscussionCounter component', () => {
     let toggleAllButton;
     const updateStoreWithExpanded = (expanded) => {
       const discussion = { ...discussionMock, expanded };
-      store.commit(types.SET_INITIAL_DISCUSSIONS, [discussion]);
+      store.commit(types.ADD_OR_UPDATE_DISCUSSIONS, [discussion]);
       store.dispatch('updateResolvableDiscussionsCounts');
       wrapper = shallowMount(DiscussionCounter, { store, localVue });
       toggleAllButton = wrapper.find('.toggle-all-discussions-btn');
diff --git a/spec/frontend/notes/stores/actions_spec.js b/spec/frontend/notes/stores/actions_spec.js
index 2ff65d3f47e..bbe074f0105 100644
--- a/spec/frontend/notes/stores/actions_spec.js
+++ b/spec/frontend/notes/stores/actions_spec.js
@@ -119,7 +119,7 @@ describe('Actions Notes Store', () => {
         actions.setInitialNotes,
         [individualNote],
         { notes: [] },
-        [{ type: 'SET_INITIAL_DISCUSSIONS', payload: [individualNote] }],
+        [{ type: 'ADD_OR_UPDATE_DISCUSSIONS', payload: [individualNote] }],
         [],
         done,
       );
@@ -1395,4 +1395,93 @@ describe('Actions Notes Store', () => {
       );
     });
   });
+
+  describe('fetchDiscussions', () => {
+    const discussion = { notes: [] };
+
+    afterEach(() => {
+      window.gon = {};
+    });
+
+    it('updates the discussions and dispatches `updateResolvableDiscussionsCounts`', (done) => {
+      axiosMock.onAny().reply(200, { discussion });
+      testAction(
+        actions.fetchDiscussions,
+        {},
+        null,
+        [
+          { type: mutationTypes.ADD_OR_UPDATE_DISCUSSIONS, payload: { discussion } },
+          { type: mutationTypes.SET_FETCHING_DISCUSSIONS, payload: false },
+        ],
+        [{ type: 'updateResolvableDiscussionsCounts' }],
+        done,
+      );
+    });
+
+    it('dispatches `fetchDiscussionsBatch` action if `paginatedIssueDiscussions` feature flag is enabled', (done) => {
+      window.gon = { features: { paginatedIssueDiscussions: true } };
+
+      testAction(
+        actions.fetchDiscussions,
+        { path: 'test-path', filter: 'test-filter', persistFilter: 'test-persist-filter' },
+        null,
+        [],
+        [
+          {
+            type: 'fetchDiscussionsBatch',
+            payload: {
+              config: {
+                params: { notes_filter: 'test-filter', persist_filter: 'test-persist-filter' },
+              },
+              path: 'test-path',
+              perPage: 20,
+            },
+          },
+        ],
+        done,
+      );
+    });
+  });
+
+  describe('fetchDiscussionsBatch', () => {
+    const discussion = { notes: [] };
+
+    const config = {
+      params: { notes_filter: 'test-filter', persist_filter: 'test-persist-filter' },
+    };
+
+    const actionPayload = { config, path: 'test-path', perPage: 20 };
+
+    it('updates the discussions and dispatches `updateResolvableDiscussionsCounts if there are no headers', (done) => {
+      axiosMock.onAny().reply(200, { discussion }, {});
+      testAction(
+        actions.fetchDiscussionsBatch,
+        actionPayload,
+        null,
+        [
+          { type: mutationTypes.ADD_OR_UPDATE_DISCUSSIONS, payload: { discussion } },
+          { type: mutationTypes.SET_FETCHING_DISCUSSIONS, payload: false },
+        ],
+        [{ type: 'updateResolvableDiscussionsCounts' }],
+        done,
+      );
+    });
+
+    it('dispatches itself if there is `x-next-page-cursor` header', (done) => {
+      axiosMock.onAny().reply(200, { discussion }, { 'x-next-page-cursor': 1 });
+      testAction(
+        actions.fetchDiscussionsBatch,
+        actionPayload,
+        null,
+        [{ type: mutationTypes.ADD_OR_UPDATE_DISCUSSIONS, payload: { discussion } }],
+        [
+          {
+            type: 'fetchDiscussionsBatch',
+            payload: { ...actionPayload, perPage: 30, cursor: 1 },
+          },
+        ],
+        done,
+      );
+    });
+  });
 });
diff --git a/spec/frontend/notes/stores/mutation_spec.js b/spec/frontend/notes/stores/mutation_spec.js
index 99e24f724f4..c9e24039b64 100644
--- a/spec/frontend/notes/stores/mutation_spec.js
+++ b/spec/frontend/notes/stores/mutation_spec.js
@@ -159,7 +159,7 @@ describe('Notes Store mutations', () => {
     });
   });
 
-  describe('SET_INITIAL_DISCUSSIONS', () => {
+  describe('ADD_OR_UPDATE_DISCUSSIONS', () => {
     it('should set the initial notes received', () => {
       const state = {
         discussions: [],
@@ -169,15 +169,17 @@ describe('Notes Store mutations', () => {
         individual_note: true,
         notes: [
           {
+            id: 100,
             note: '1',
           },
           {
+            id: 101,
             note: '2',
           },
         ],
       };
 
-      mutations.SET_INITIAL_DISCUSSIONS(state, [note, legacyNote]);
+      mutations.ADD_OR_UPDATE_DISCUSSIONS(state, [note, legacyNote]);
 
       expect(state.discussions[0].id).toEqual(note.id);
       expect(state.discussions[1].notes[0].note).toBe(legacyNote.notes[0].note);
@@ -190,7 +192,7 @@ describe('Notes Store mutations', () => {
         discussions: [],
       };
 
-      mutations.SET_INITIAL_DISCUSSIONS(state, [
+      mutations.ADD_OR_UPDATE_DISCUSSIONS(state, [
         {
           ...note,
           diff_file: {
@@ -208,7 +210,7 @@ describe('Notes Store mutations', () => {
         discussions: [],
       };
 
-      mutations.SET_INITIAL_DISCUSSIONS(state, [
+      mutations.ADD_OR_UPDATE_DISCUSSIONS(state, [
         {
           ...note,
           diff_file: {