Remove trailing new lines from GTest names

.coderabbit.yaml

@@ -67,6 +67,15 @@ reviews:
         - Verify GPU availability checks before tests
         - Check for proper error handling and meaningful error messages
 
+    - path: "cpp/tests/**/*"
+      instructions: |
+        For GTest parameterized test parameter structs:
+        - Flag any `operator<<` overload or `PrintTo` function used to stringify test
+          parameters (i.e. feeds into a GTest test name) that emits `std::endl` or a
+          literal `"\n"`. GTest builds the parameterized test name from this stream
+          output, and a trailing newline breaks exact-match tooling such as
+          `ctest --tests-from-file`. Flag as HIGH priority.
+
 knowledge_base:
   opt_out: false
   code_guidelines:

cpp/REVIEW_GUIDELINES.md

@@ -79,6 +79,7 @@
 ### Test Quality
 - Missing validation of numerical correctness
 - **Using external datasets** (tests must not depend on external resources; use synthetic data or bundled datasets)
+- **Trailing newline in GTest parameterized test names** (`operator<<` overloads or `PrintTo` functions used to stringify test parameters must not emit `std::endl` or `"\n"`; GTest uses the stream output to build the test name, and a trailing newline breaks exact-match tooling like `ctest --tests-from-file`)
 
 ## MEDIUM Issues (Comment Selectively)
 
@@ -304,6 +305,7 @@ cudaStreamCreate(&per_device_stream);
 - [ ] Are all datasets synthetic or bundled (no external resource dependencies)?
 - [ ] Is numerical correctness validated?
 - [ ] Are edge cases tested (empty, single element, extreme values)?
+- [ ] If an `operator<<`/`PrintTo` is used to name parameterized GTest cases, does it avoid `std::endl`/`"\n"` (a trailing newline in the generated name breaks `ctest --tests-from-file` exact matching)?
 
 ---
 

cpp/tests/neighbors/all_neighbors.cuh

@@ -53,7 +53,7 @@ inline ::std::ostream& operator<<(::std::ostream& os, const AllNeighborsInputs&
      << ", metric=" << static_cast<int>(std::get<1>(p.build_algo_metric_recall))
      << ", clusters=" << std::get<0>(p.cluster_nearestcluster)
      << ", overlap_factor=" << std::get<1>(p.cluster_nearestcluster)
-     << ", output_on_host=" << p.output_on_host << std::endl;
+     << ", output_on_host=" << p.output_on_host;
   return os;
 }