1 files changed, 167 insertions, 0 deletions
diff --git a/spec/frontend/pager_spec.js b/spec/frontend/pager_spec.js
new file mode 100644
index 00000000000..d7177a32cde
--- /dev/null
+++ b/spec/frontend/pager_spec.js
@@ -0,0 +1,167 @@
+import $ from 'jquery';
+import MockAdapter from 'axios-mock-adapter';
+import axios from '~/lib/utils/axios_utils';
+import Pager from '~/pager';
+import { removeParams } from '~/lib/utils/url_utility';
+
+jest.mock('~/lib/utils/url_utility', () => ({
+  removeParams: jest.fn().mockName('removeParams'),
+}));
+
+describe('pager', () => {
+  let axiosMock;
+
+  beforeEach(() => {
+    axiosMock = new MockAdapter(axios);
+  });
+
+  afterEach(() => {
+    axiosMock.restore();
+  });
+
+  describe('init', () => {
+    const originalHref = window.location.href;
+
+    beforeEach(() => {
+      setFixtures('<div class="content_list"></div><div class="loading"></div>');
+      jest.spyOn($.fn, 'endlessScroll').mockImplementation();
+    });
+
+    afterEach(() => {
+      window.history.replaceState({}, null, originalHref);
+    });
+
+    it('should use data-href attribute from list element', () => {
+      const href = `${gl.TEST_HOST}/some_list.json`;
+      setFixtures(`<div class="content_list" data-href="${href}"></div>`);
+      Pager.init();
+
+      expect(Pager.url).toBe(href);
+    });
+
+    it('should use current url if data-href attribute not provided', () => {
+      const href = `${gl.TEST_HOST}/some_list`;
+      removeParams.mockReturnValue(href);
+      Pager.init();
+
+      expect(Pager.url).toBe(href);
+    });
+
+    it('should get initial offset from query parameter', () => {
+      window.history.replaceState({}, null, '?offset=100');
+      Pager.init();
+
+      expect(Pager.offset).toBe(100);
+    });
+
+    it('keeps extra query parameters from url', () => {
+      window.history.replaceState({}, null, '?filter=test&offset=100');
+      const href = `${gl.TEST_HOST}/some_list?filter=test`;
+      removeParams.mockReturnValue(href);
+      Pager.init();
+
+      expect(removeParams).toHaveBeenCalledWith(['limit', 'offset']);
+      expect(Pager.url).toEqual(href);
+    });
+  });
+
+  describe('getOld', () => {
+    const urlRegex = /(.*)some_list(.*)$/;
+
+    function mockSuccess(count = 0) {
+      axiosMock.onGet(urlRegex).reply(200, {
+        count,
+        html: '',
+      });
+    }
+
+    function mockError() {
+      axiosMock.onGet(urlRegex).networkError();
+    }
+
+    beforeEach(() => {
+      setFixtures(
+        '<div class="content_list" data-href="/some_list"></div><div class="loading"></div>',
+      );
+      jest.spyOn(axios, 'get');
+
+      Pager.init();
+    });
+
+    it('shows loader while loading next page', done => {
+      mockSuccess();
+
+      jest.spyOn(Pager.loading, 'show').mockImplementation(() => {});
+      Pager.getOld();
+
+      setImmediate(() => {
+        expect(Pager.loading.show).toHaveBeenCalled();
+
+        done();
+      });
+    });
+
+    it('hides loader on success', done => {
+      mockSuccess();
+
+      jest.spyOn(Pager.loading, 'hide').mockImplementation(() => {});
+      Pager.getOld();
+
+      setImmediate(() => {
+        expect(Pager.loading.hide).toHaveBeenCalled();
+
+        done();
+      });
+    });
+
+    it('hides loader on error', done => {
+      mockError();
+
+      jest.spyOn(Pager.loading, 'hide').mockImplementation(() => {});
+      Pager.getOld();
+
+      setImmediate(() => {
+        expect(Pager.loading.hide).toHaveBeenCalled();
+
+        done();
+      });
+    });
+
+    it('sends request to url with offset and limit params', done => {
+      Pager.offset = 100;
+      Pager.limit = 20;
+      Pager.getOld();
+
+      setImmediate(() => {
+        const [url, params] = axios.get.mock.calls[0];
+
+        expect(params).toEqual({
+          params: {
+            limit: 20,
+            offset: 100,
+          },
+        });
+
+        expect(url).toBe('/some_list');
+
+        done();
+      });
+    });
+
+    it('disables if return count is less than limit', done => {
+      Pager.offset = 0;
+      Pager.limit = 20;
+
+      mockSuccess(1);
+      jest.spyOn(Pager.loading, 'hide').mockImplementation(() => {});
+      Pager.getOld();
+
+      setImmediate(() => {
+        expect(Pager.loading.hide).toHaveBeenCalled();
+        expect(Pager.disable).toBe(true);
+
+        done();
+      });
+    });
+  });
+});