Don’t use using directives (“using namespace”) in tests

minidump/minidump_file_writer_test.cc

Index: minidump/minidump_file_writer_test.cc
diff --git a/minidump/minidump_file_writer_test.cc b/minidump/minidump_file_writer_test.cc
index 0ccc0f8efaa9d495d34c203e47feb76c1ec99360..611dce820390b84b591c3f2953ff28509fe4c3f6 100644
--- a/minidump/minidump_file_writer_test.cc
+++ b/minidump/minidump_file_writer_test.cc
@@ -26,11 +26,10 @@
 #include "util/file/file_writer.h"
 #include "util/file/string_file_writer.h"
 
+namespace crashpad {
+namespace test {
 namespace {
 
-using namespace crashpad;
-using namespace crashpad::test;
-
 TEST(MinidumpFileWriter, Empty) {
   MinidumpFileWriter minidump_file;
   StringFileWriter file_writer;
@@ -262,3 +261,5 @@ TEST(MinidumpFileWriterDeathTest, SameStreamType) {
 }
 
 }  // namespace
+}  // namespace test
+}  // namespace crashpad