regulators: Add inventory path to Chassis class

A previous commit added the "inventory_path" property to the "chassis"
object in the JSON configuration file.

This commit adds that new property to the C++ implementation:
* Chassis class and associated gtests
* JSON configuration file parser functions and associated gtests
* Other gtests affected by the change to the Chassis constructor

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I7406f874263d01e6faa2b8c333cb1baf915cf2ac
diff --git a/phosphor-regulators/test/sensor_monitoring_tests.cpp b/phosphor-regulators/test/sensor_monitoring_tests.cpp
index f2f4359..4dfd415 100644
--- a/phosphor-regulators/test/sensor_monitoring_tests.cpp
+++ b/phosphor-regulators/test/sensor_monitoring_tests.cpp
@@ -50,6 +50,9 @@
 using ::testing::Throw;
 using ::testing::TypedEq;
 
+static const std::string chassisInvPath{
+    "/xyz/openbmc_project/inventory/system/chassis"};
+
 TEST(SensorMonitoringTests, Constructor)
 {
     std::vector<std::unique_ptr<Action>> actions{};
@@ -115,7 +118,7 @@
         std::vector<std::unique_ptr<Device>> devices{};
         devices.emplace_back(std::move(device));
         std::unique_ptr<Chassis> chassis =
-            std::make_unique<Chassis>(1, std::move(devices));
+            std::make_unique<Chassis>(1, chassisInvPath, std::move(devices));
         Chassis* chassisPtr = chassis.get();
 
         // Create System that contains Chassis
@@ -198,7 +201,7 @@
         std::vector<std::unique_ptr<Device>> devices{};
         devices.emplace_back(std::move(device));
         std::unique_ptr<Chassis> chassis =
-            std::make_unique<Chassis>(1, std::move(devices));
+            std::make_unique<Chassis>(1, chassisInvPath, std::move(devices));
         Chassis* chassisPtr = chassis.get();
 
         // Create System that contains Chassis