diff --git a/unknown_case_counter/tests/data/sample_delta_cases.csv b/unknown_case_counter/tests/data/sample_delta_cases.csv
new file mode 100644
index 0000000..451acdf
--- /dev/null
+++ b/unknown_case_counter/tests/data/sample_delta_cases.csv
@@ -0,0 +1,8 @@
+case_id,previous_status,new_status,unknown_reason
+C001,PASS,Unknown,NetworkError
+C002,FAIL,Unknown,Timeout
+C003,PASS,PASS,
+C004,FAIL,Unknown,MissingArtifact
+C005,PASS,Unknown,SchemaMismatch
+C006,FAIL,FAIL,
+C007,PASS,Unknown,NetworkError