1 files changed, 27 insertions, 0 deletions
diff --git a/test/unit/specs/components/timeline.spec.js b/test/unit/specs/components/timeline.spec.js
new file mode 100644
index 00000000..0c8674a8
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+++ b/test/unit/specs/components/timeline.spec.js
@@ -0,0 +1,27 @@
+import { getExcludedStatusIdsByPinning } from 'src/components/timeline/timeline.js'
+
+describe('Timeline', () => {
+  describe('getExcludedStatusIdsByPinning', () => {
+    const mockStatuses = (ids) => ids.map(id => ({ id }))
+
+    it('should return only members of both pinnedStatusIds and ids of the given statuses', () => {
+      const statusIds = [1, 2, 3, 4]
+      const statuses = mockStatuses(statusIds)
+      const pinnedStatusIds = [1, 3, 5]
+      const result = getExcludedStatusIdsByPinning(statuses, pinnedStatusIds)
+      result.forEach(item => {
+        expect(item).to.be.oneOf(statusIds)
+        expect(item).to.be.oneOf(pinnedStatusIds)
+      })
+    })
+
+    it('should return ids of pinned statuses not posted before any unpinned status', () => {
+      const pinnedStatusIdSet1 = ['PINNED1', 'PINNED2']
+      const pinnedStatusIdSet2 = ['PINNED3', 'PINNED4']
+      const pinnedStatusIds = [...pinnedStatusIdSet1, ...pinnedStatusIdSet2]
+      const statusIds = [...pinnedStatusIdSet1, 'UNPINNED1', ...pinnedStatusIdSet2]
+      const statuses = mockStatuses(statusIds)
+      expect(getExcludedStatusIdsByPinning(statuses, pinnedStatusIds)).to.eql(pinnedStatusIdSet1)
+    })
+  })
+})