test: Add test-driver, minor refactoring

Add the test driver so we can run unit tests with the check target.

Drop GTEST_CPPFLAGS - gtest has proper pkg-config support now.

Default not-found messages are sufficient - use those.

Change-Id: I887f6bc46a029b6b23254da7508745952f865869
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index 98b521a..eb95144 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -7,6 +7,8 @@
 noinst_PROGRAMS = phosphor-inventory-test
 noinst_LTLIBRARIES = libtest.la
 
+TESTS = ${check_PROGRAMS}
+
 extra_yamldir=$(top_srcdir)/example/extra_interfaces.d
 
 phosphor_inventory_test_SOURCES = test.cpp