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

snapshot/system_snapshot_mac_test.cc

Index: snapshot/system_snapshot_mac_test.cc
diff --git a/snapshot/system_snapshot_mac_test.cc b/snapshot/system_snapshot_mac_test.cc
index 1f9d10174852cf337a0207220a6806d1d56caa09..bce1137d4efac06906317dff4fc869122be57c39 100644
--- a/snapshot/system_snapshot_mac_test.cc
+++ b/snapshot/system_snapshot_mac_test.cc
@@ -25,11 +25,10 @@
 #include "util/mac/process_reader.h"
 #include "util/test/errors.h"
 
+namespace crashpad {
+namespace test {
 namespace {
 
-using namespace crashpad;
-using namespace crashpad::test;
-
 // SystemSnapshotMac objects would be cumbersome to construct in each test that
 // requires one, because of the repetitive and mechanical work necessary to set
 // up a ProcessReader and timeval, along with the checks to verify that these
@@ -173,3 +172,5 @@ TEST_F(SystemSnapshotMacTest, TimeZone) {
 }
 
 }  // namespace
+}  // namespace test
+}  // namespace crashpad