diff --git a/util/net/http_body_gzip_test.cc b/util/net/http_body_gzip_test.cc
index 9dafb37..926dfca 100644
--- a/util/net/http_body_gzip_test.cc
+++ b/util/net/http_body_gzip_test.cc
@@ -133,7 +133,7 @@
 std::string MakeString(size_t size) {
   std::string string;
   for (size_t i = 0; i < size; ++i) {
-    string.append(1, (i % 256) ^ ((i >> 8) % 256));
+    string.append(1, static_cast<char>((i % 256) ^ ((i >> 8) % 256)));
   }
   return string;
 }
diff --git a/util/process/process_memory_test.cc b/util/process/process_memory_test.cc
index 3e3e058..f00a6b9 100644
--- a/util/process/process_memory_test.cc
+++ b/util/process/process_memory_test.cc
@@ -104,7 +104,7 @@
   *region_size = 4 * base::GetPageSize();
   region->reset(new char[*region_size]);
   for (size_t index = 0; index < *region_size; ++index) {
-    (*region)[index] = index % 256;
+    (*region)[index] = static_cast<char>(index % 256);
   }
 }
 
@@ -367,7 +367,7 @@
 void DoReadUnmappedChildMainSetup(void* page) {
   char* region = reinterpret_cast<char*>(page);
   for (size_t index = 0; index < base::GetPageSize(); ++index) {
-    region[index] = index % 256;
+    region[index] = static_cast<char>(index % 256);
   }
 }