Add the expected table for documentations and assert on changes.

1 files changed, 34 insertions, 6 deletions

diff --git a/container-search/src/test/java/com/yahoo/search/dispatch/TopKEstimatorTest.java b/container-search/src/test/java/com/yahoo/search/dispatch/TopKEstimatorTest.java
index bd06a34622f..a0f1b32ec13 100644
--- a/container-search/src/test/java/com/yahoo/search/dispatch/TopKEstimatorTest.java
+++ b/container-search/src/test/java/com/yahoo/search/dispatch/TopKEstimatorTest.java
@@ -103,23 +103,51 @@ public class TopKEstimatorTest {
         assertEquals(4304, estimator.estimateK(40000, 10));
         assertEquals(8429, estimator.estimateK(80000, 10));
         assertEquals(10480, estimator.estimateK(100000, 10));
+        String expected =
+                "Prob/Hits: 1.0000000000 0.9999000000 0.9999900000 0.9999990000 0.9999999000 0.9999999900 0.9999999990 0.9999999999\n" +
+                "       10:       10.000        6.000        7.000        8.000        9.000       10.000       10.000       10.000\n" +
+                "       20:       10.000        4.500        5.000        5.500        6.500        7.000        7.500        8.000\n" +
+                "       40:       10.000        3.500        4.000        4.250        4.750        5.250        5.500        6.000\n" +
+                "       80:       10.000        2.750        3.000        3.250        3.625        3.875        4.250        4.500\n" +
+                "      100:       10.000        2.600        2.800        3.100        3.300        3.600        3.900        4.200\n" +
+                "      200:       10.000        2.100        2.250        2.450        2.650        2.800        3.000        3.200\n" +
+                "      400:       10.000        1.775        1.900        2.025        2.150        2.275        2.425        2.575\n" +
+                "      800:       10.000        1.538        1.625        1.713        1.813        1.900        2.000        2.100\n" +
+                "     1000:       10.000        1.480        1.560        1.640        1.720        1.810        1.890        1.990\n" +
+                "     2000:       10.000        1.340        1.395        1.450        1.510        1.570        1.630        1.695\n" +
+                "     4000:       10.000        1.240        1.280        1.320        1.360        1.403        1.445        1.493\n" +
+                "     8000:       10.000        1.170        1.198        1.225        1.254        1.284        1.315        1.348\n" +
+                "    10000:       10.000        1.152        1.177        1.202        1.227        1.254        1.282        1.311\n" +
+                "    20000:       10.000        1.108        1.125        1.143        1.161        1.180        1.199        1.220\n" +
+                "    40000:       10.000        1.076        1.088        1.101        1.114        1.127        1.141        1.156\n" +
+                "    80000:       10.000        1.054        1.062        1.071        1.080        1.090        1.100        1.110\n" +
+                "   100000:       10.000        1.048        1.056        1.064        1.072        1.080        1.089        1.098\n";
+        assertEquals(expected, dumpProbability(10));
+    }
+
+    /**
+     * This make a table showing how many more hits will be fetched as a factor of hits requested.
+     * It shows how it varies with probability and hits requested for a given number of partitions.
+     */
+    private String dumpProbability(int numPartitions) {
+        TopKEstimator estimator = new TopKEstimator(30, 0.9999);
         int [] K = {10, 20, 40, 80, 100, 200, 400, 800, 1000, 2000, 4000, 8000, 10000, 20000, 40000, 80000, 100000};
         double [] P = {1.0, 0.9999, 0.99999, 0.999999, 0.9999999, 0.99999999, 0.999999999, 0.9999999999};
-        int n = 10;
+        int n = numPartitions;
         StringBuilder sb = new StringBuilder();
         sb.append(String.format("Prob/Hits:"));
         for (double p : P) {
             sb.append(String.format(" %1.10f", p));
         }
-        System.out.println(sb.toString());
+        sb.append("\n");
         for (int k : K) {
-            sb = new StringBuilder();
-            sb.append(String.format("%11d:", k));
+            sb.append(String.format("%9d:", k));
             for (double p : P) {
-                sb.append(String.format("    %2.3f    ", (double)(estimator.estimateK(k, n, p)*n) / k));
+                sb.append(String.format("%13.3f", (double)(estimator.estimateK(k, n, p)*n) / k));
             }
-            System.out.println(sb.toString());
+            sb.append("\n");
         }
+        return sb.toString();
     }
 
 }