Add time Manager to handle property changes callback

1. Implement time::Manager who registers property change signal for time
mode and owner;
2. Add PropertyChangeListner interface to handle the callback;
3. Make EpochBase to implement the interface.

Change-Id: I185580ae37353e1ed82a47e4905fb22e269ac09d
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/test/TestManager.cpp b/test/TestManager.cpp
new file mode 100644
index 0000000..4d9ae73
--- /dev/null
+++ b/test/TestManager.cpp
@@ -0,0 +1,76 @@
+#include <sdbusplus/bus.hpp>
+#include <gtest/gtest.h>
+
+#include "types.hpp"
+#include "manager.hpp"
+
+namespace phosphor
+{
+namespace time
+{
+
+class TestManager : public testing::Test
+{
+    public:
+        sdbusplus::bus::bus bus;
+        Manager manager;
+
+        TestManager()
+            : bus(sdbusplus::bus::new_default()),
+              manager(bus)
+        {
+            // Empty
+        }
+
+        // Proxies for Manager's private members and functions
+         Mode getTimeMode()
+        {
+            return manager.timeMode;
+        }
+        Owner getTimeOwner()
+        {
+            return manager.timeOwner;
+        }
+        Mode convertToMode(const std::string& mode)
+        {
+            return Manager::convertToMode(mode);
+        }
+        Owner convertToOwner(const std::string& owner)
+        {
+            return Manager::convertToOwner(owner);
+        }
+};
+
+TEST_F(TestManager, empty)
+{
+    EXPECT_EQ(Mode::NTP, getTimeMode());
+    EXPECT_EQ(Owner::BMC, getTimeOwner());
+}
+
+TEST_F(TestManager, convertToMode)
+{
+    EXPECT_EQ(Mode::NTP, convertToMode("NTP"));
+    EXPECT_EQ(Mode::MANUAL, convertToMode("MANUAL"));
+
+    // All unrecognized strings are mapped to Ntp
+    EXPECT_EQ(Mode::NTP, convertToMode(""));
+    EXPECT_EQ(Mode::NTP, convertToMode("Manual"));
+    EXPECT_EQ(Mode::NTP, convertToMode("whatever"));
+}
+
+
+TEST_F(TestManager, convertToOwner)
+{
+    EXPECT_EQ(Owner::BMC, convertToOwner("BMC"));
+    EXPECT_EQ(Owner::HOST, convertToOwner("HOST"));
+    EXPECT_EQ(Owner::SPLIT, convertToOwner("SPLIT"));
+    EXPECT_EQ(Owner::BOTH, convertToOwner("BOTH"));
+
+    // All unrecognized strings are mapped to Bmc
+    EXPECT_EQ(Owner::BMC, convertToOwner(""));
+    EXPECT_EQ(Owner::BMC, convertToOwner("Split"));
+    EXPECT_EQ(Owner::BMC, convertToOwner("xyz"));
+}
+
+}
+}