sensors/zones: place in namespace and cleanup

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I527dbc8477a232945f696227a7b0b2adbee45175
diff --git a/test/pid_json_unittest.cpp b/test/pid_json_unittest.cpp
index 2bd7d35..0e767f9 100644
--- a/test/pid_json_unittest.cpp
+++ b/test/pid_json_unittest.cpp
@@ -3,6 +3,11 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
+namespace pid_control
+{
+namespace
+{
+
 TEST(ZoneFromJson, emptyZone)
 {
     // There is a zone key, but it's empty.
@@ -199,4 +204,7 @@
                      1.0);
 
     EXPECT_DOUBLE_EQ(zoneConfig[1].minThermalOutput, 3000.0);
-}
\ No newline at end of file
+}
+
+} // namespace
+} // namespace pid_control