diff --git a/heatmap_visualization/tests/data/sample_logdata.json b/heatmap_visualization/tests/data/sample_logdata.json
new file mode 100644
index 0000000..302dca7
--- /dev/null
+++ b/heatmap_visualization/tests/data/sample_logdata.json
@@ -0,0 +1,52 @@
+[
+  {
+    "worker_start_offset": -1.0,
+    "expires_at_dist_hours": 4.5,
+    "retry_total_overhead_ms": 120.0
+  },
+  {
+    "worker_start_offset": 0.0,
+    "expires_at_dist_hours": 5.0,
+    "retry_total_overhead_ms": 85.0
+  },
+  {
+    "worker_start_offset": 0.5,
+    "expires_at_dist_hours": 5.3,
+    "retry_total_overhead_ms": 200.0
+  },
+  {
+    "worker_start_offset": 1.0,
+    "expires_at_dist_hours": 5.7,
+    "retry_total_overhead_ms": 350.0
+  },
+  {
+    "worker_start_offset": 2.0,
+    "expires_at_dist_hours": 6.2,
+    "retry_total_overhead_ms": 620.0
+  },
+  {
+    "worker_start_offset": 3.0,
+    "expires_at_dist_hours": 6.9,
+    "retry_total_overhead_ms": 810.0
+  },
+  {
+    "worker_start_offset": -2.5,
+    "expires_at_dist_hours": 3.5,
+    "retry_total_overhead_ms": 60.0
+  },
+  {
+    "worker_start_offset": 4.0,
+    "expires_at_dist_hours": 7.5,
+    "retry_total_overhead_ms": 950.0
+  },
+  {
+    "worker_start_offset": 5.0,
+    "expires_at_dist_hours": 8.1,
+    "retry_total_overhead_ms": 1100.0
+  },
+  {
+    "worker_start_offset": -0.5,
+    "expires_at_dist_hours": 4.8,
+    "retry_total_overhead_ms": 95.0
+  }
+]
\ No newline at end of file