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

util/file/string_file_writer_test.cc

Index: util/file/string_file_writer_test.cc
diff --git a/util/file/string_file_writer_test.cc b/util/file/string_file_writer_test.cc
index b55c778e90e9ecbfc1e71b708791343aa18ccdad..d6ea2e496a1e3be4c2ce6e14e60da3d0e11adf83 100644
--- a/util/file/string_file_writer_test.cc
+++ b/util/file/string_file_writer_test.cc
@@ -19,10 +19,10 @@
 
 #include "gtest/gtest.h"
 
+namespace crashpad {
+namespace test {
 namespace {
 
-using namespace crashpad;
-
 TEST(StringFileWriter, EmptyFile) {
   StringFileWriter writer;
   EXPECT_TRUE(writer.string().empty());
@@ -376,3 +376,5 @@ TEST(StringFileWriter, SeekInvalid) {
 }
 
 }  // namespace
+}  // namespace test
+}  // namespace crashpad