regulators: Fix IDMap testcases for duplicate IDs

A recent commit enhanced the IDMap class to detect duplicate IDs.

The corresponding testcases were missing an ADD_FAILURE() statement
covering the case where the expected exception was not thrown.

Fixed the testcases by adding the ADD_FAILURE() statements.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I5a88f446e4712e550e3e66dd2c359971e1f8a9b4
diff --git a/phosphor-regulators/test/id_map_tests.cpp b/phosphor-regulators/test/id_map_tests.cpp
index 991949b..0b541a4 100644
--- a/phosphor-regulators/test/id_map_tests.cpp
+++ b/phosphor-regulators/test/id_map_tests.cpp
@@ -71,6 +71,7 @@
         Device device2{"vio_reg", true, "/system/chassis/motherboard/vio_reg2",
                        std::move(i2cInterface)};
         idMap.addDevice(device2);
+        ADD_FAILURE() << "Should not have reached this line.";
     }
     catch (const std::invalid_argument& error)
     {
@@ -113,6 +114,7 @@
     {
         Rail rail2{"vio0"};
         idMap.addRail(rail2);
+        ADD_FAILURE() << "Should not have reached this line.";
     }
     catch (const std::invalid_argument& error)
     {
@@ -155,6 +157,7 @@
     {
         Rule rule2{"set_voltage_rule", std::vector<std::unique_ptr<Action>>{}};
         idMap.addRule(rule2);
+        ADD_FAILURE() << "Should not have reached this line.";
     }
     catch (const std::invalid_argument& error)
     {