fix all test failures

Change-Id: Iead2d25adc95ad1d7d2252a854dc8ba854c90889
diff --git a/tests/database-fixture.hpp b/tests/database-fixture.hpp
index 4223c98..06c63f5 100644
--- a/tests/database-fixture.hpp
+++ b/tests/database-fixture.hpp
@@ -40,10 +40,7 @@
 public:
   DatabaseFixture()
   {
-    auto parentDir = boost::filesystem::path(getenv("TEST_HOME"));
-    if (!boost::filesystem::exists(parentDir)) {
-      boost::filesystem::create_directory(parentDir);
-    }
+    auto parentDir = boost::filesystem::path(getenv("HOME"));
     dbDir = parentDir / ".ndncert";
     if (!boost::filesystem::exists(dbDir)) {
       boost::filesystem::create_directory(dbDir);