Duplicate test case
A test case that checks behavior another case in the suite already checks, often written because searching the library took longer than writing a new one. Duplicates inflate coverage figures, double the maintenance on every requirement change and make one defect look like several failures. They rarely announce themselves, so finding them takes a deliberate review pass.
Also called: Redundant test case
Exact copies are the easy part
A case copied and pasted into a second suite is found by comparing titles and steps, and any tool or spreadsheet filter can do that. The expensive duplicates are the near-duplicates: Login with valid credentials in one suite, User can sign in with email and password in another, written a year apart by different people. Text comparison misses them. A reviewer who knows the feature catches them, and so does semantic comparison that looks at what the case verifies instead of how it is worded.
Where they come from
The usual sources are predictable. Two libraries merged during a migration. Cases rewritten for each release instead of edited. Two teams testing a shared feature from their own suites. And, more recently, generated test cases accepted in bulk without a check against what the suite already holds.
Not every overlap is a duplicate
The same steps with different data, or the same flow on a different platform, are often intentional. A useful rule: merge only when the condition and the expected result are both the same. When two similar cases are deliberate, record that, or the next review will flag them again.
Merging without losing history
Keep the clearer of the two and retire the other. Before deleting, check what hangs on the one you are about to remove: execution history, linked requirements, linked defects, and the test case IDs that automated tests report against. Deleting the case that automation points at quietly breaks result mapping.
In QAM Hub
On Advanced, the Quality Analyzer (Quality & Coverage Analytics on the pricing page) reviews test cases in batches and flags duplicates, including semantic ones a text comparison would miss, with a quote from the case as evidence and a suggested fix. Marking a pair Not a duplicate stops it from being flagged again. The review method in general is covered in how to find duplicate and low-quality test cases.