Clarify in mju_boxQP test that for the synthetic test set, the average number of factorizations is expected to be 5 or less, while the worst case is expected to be 6 or less.

PiperOrigin-RevId: 691037804
Change-Id: Id0bc8bedf08d623efcacbe696775f0ef0f6781b9

test/engine/engine_util_solve_test.cc

@@ -16,8 +16,12 @@
 
 #include "src/engine/engine_util_solve.h"
 
+#include <cstddef>
+#include <iostream>
 #include <random>
 #include <iomanip>
+#include <string>
+#include <vector>
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ -332,12 +336,21 @@ TEST_F(BoxQPTest, BoundedQPvariations) {
           string slog(log);
           string factorstr = "factorizations=";
           std::size_t index = slog.find(factorstr) + factorstr.length();
-          factorizations += std::stoi(slog.substr(index, 3));
+          int num_factor = std::stoi(slog.substr(index, 3));
+
+          // never more than 6 factorizations
+          EXPECT_LE(num_factor, 6);
+
+          factorizations += num_factor;
           count++;
         }
       }
     }
     double meanfactor = ((double)factorizations) / count;
+
+    // average of 4.5 factorizations is expected
+    EXPECT_LE(meanfactor, 5.0);
+
     std::cerr << "n=" << setw(3) << n
               << ": average of " << meanfactor << " factorizations\n";
   }