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

minidump/minidump_string_writer_test.cc

Index: minidump/minidump_string_writer_test.cc
diff --git a/minidump/minidump_string_writer_test.cc b/minidump/minidump_string_writer_test.cc
index 682da831f346d4520116d2ff2265b042867581cc..9e684cef85f0dcc9b0ed2d692292480ac14d5914 100644
--- a/minidump/minidump_string_writer_test.cc
+++ b/minidump/minidump_string_writer_test.cc
@@ -24,10 +24,10 @@
 #include "gtest/gtest.h"
 #include "util/file/string_file_writer.h"
 
+namespace crashpad {
+namespace test {
 namespace {
 
-using namespace crashpad;
-
 const MINIDUMP_STRING* MinidumpStringCast(const StringFileWriter& file_writer) {
   return reinterpret_cast<const MINIDUMP_STRING*>(&file_writer.string()[0]);
 }
@@ -199,3 +199,5 @@ TEST(MinidumpStringWriter, MinidumpUTF8StringWriter) {
 }
 
 }  // namespace
+}  // namespace test
+}  // namespace crashpad