2 files changed, 29 insertions, 0 deletions
diff --git a/llvm/lib/Fuzzer/test/FuzzerUnittest.cpp b/llvm/lib/Fuzzer/test/FuzzerUnittest.cpp
index 4992ef57b6c..5eb915a9162 100644
--- a/llvm/lib/Fuzzer/test/FuzzerUnittest.cpp
+++ b/llvm/lib/Fuzzer/test/FuzzerUnittest.cpp
@@ -14,6 +14,7 @@
 #include "gtest/gtest.h"
 #include <memory>
 #include <set>
+#include <sstream>
 
 using namespace fuzzer;
 
@@ -636,7 +637,10 @@ static void Merge(const std::string &Input,
   Merger M;
   std::vector<std::string> NewFiles;
   EXPECT_TRUE(M.Parse(Input, true));
+  std::stringstream SS;
+  M.PrintSummary(SS);
   EXPECT_EQ(NumNewFeatures, M.Merge(&NewFiles));
+  EXPECT_EQ(M.AllFeatures(), M.ParseSummary(SS));
   EQ(NewFiles, Result);
 }
 
@@ -706,6 +710,16 @@ TEST(Merge, Good) {
   EQ(M.Files[2].Features, {1, 3, 6});
   EXPECT_EQ(3U, M.Merge(&NewFiles));
   EQ(NewFiles, {"B"});
+
+  // Same as the above, but with InitialFeatures.
+  EXPECT_TRUE(M.Parse("2\n0\nB\nC\n"
+                        "STARTED 0 1001\nDONE 0 4 5 6 \n"
+                        "STARTED 1 1002\nDONE 1 6 1 3\n"
+                        "", true));
+  EQ(M.Files[0].Features, {4, 5, 6});
+  EQ(M.Files[1].Features, {1, 3, 6});
+  EXPECT_EQ(3U, M.Merge({1, 2, 3}, &NewFiles));
+  EQ(NewFiles, {"B"});
 }
 
 TEST(Merge, Merge) {
diff --git a/llvm/lib/Fuzzer/test/merge-summary.test b/llvm/lib/Fuzzer/test/merge-summary.test
new file mode 100644
index 00000000000..df9d62dec63
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/merge-summary.test
@@ -0,0 +1,15 @@
+RUN: rm -rf %t/T1 %t/T2
+RUN: mkdir -p %t/T0 %t/T1 %t/T2
+RUN: echo ...Z.. > %t/T2/1
+RUN: echo ....E. > %t/T2/2
+RUN: echo .....R > %t/T2/3
+RUN: echo F..... > %t/T2/a
+RUN: echo .U.... > %t/T2/b
+RUN: echo ..Z... > %t/T2/c
+
+RUN: LLVMFuzzer-FullCoverageSetTest -merge=1 %t/T1 %t/T2 -save_coverage_summary=%t/SUMMARY 2>&1 | FileCheck %s --check-prefix=SAVE_SUMMARY
+SAVE_SUMMARY: MERGE-OUTER: writing coverage summary for 6 files to {{.*}}SUMMARY
+RUN: rm %t/T1/*
+RUN: LLVMFuzzer-FullCoverageSetTest -merge=1 %t/T1 %t/T2 -load_coverage_summary=%t/SUMMARY 2>&1 | FileCheck %s --check-prefix=LOAD_SUMMARY
+LOAD_SUMMARY: MERGE-OUTER: coverage summary loaded from {{.*}}SUMMAR
+LOAD_SUMMARY: MERGE-OUTER: 0 new files with 0 new features added