diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index bac943f16..574f3ff7b 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -1139,9 +1139,9 @@ Components.utils.import("resource://gre/modules/osfile.jsm");
 	
 	
 	this.getDefaultDataDir = function () {
-		// Keep data directory siloed within profile directory for tests
+		// Use special data directory for tests
 		if (Zotero.test) {
-			return OS.Path.join(OS.Constants.Path.profileDir, "test-data-dir");
+			return OS.Path.join(OS.Path.dirname(OS.Constants.Path.profileDir), "Zotero");
 		}
 		return OS.Path.join(OS.Constants.Path.homeDir, ZOTERO_CONFIG.CLIENT_NAME);
 	};
diff --git a/test/runtests.sh b/test/runtests.sh
index 4cc68f4ac..bdf24da95 100755
--- a/test/runtests.sh
+++ b/test/runtests.sh
@@ -98,8 +98,9 @@ fi
 ulimit -n 4096
 
 # Set up profile directory
-PROFILE="`mktemp -d 2>/dev/null || mktemp -d -t 'zotero-unit'`"
-mkdir "$PROFILE/extensions"
+TEMPDIR="`mktemp -d 2>/dev/null || mktemp -d -t 'zotero-unit'`"
+PROFILE="$TEMPDIR/profile"
+mkdir -p "$PROFILE/extensions"
 
 makePath ZOTERO_UNIT_PATH "$CWD"
 echo "$ZOTERO_UNIT_PATH" > "$PROFILE/extensions/zotero-unit@zotero.org"
@@ -108,7 +109,7 @@ makePath ZOTERO_PATH "`dirname "$CWD"`"
 echo "$ZOTERO_PATH" > "$PROFILE/extensions/zotero@chnm.gmu.edu"
 
 # Create data directory
-mkdir "$PROFILE/zotero"
+mkdir "$TEMPDIR/Zotero"
 
 cat <<EOF > "$PROFILE/prefs.js"
 user_pref("extensions.autoDisableScopes", 0);
@@ -139,7 +140,7 @@ if [ "$TRAVIS" = true ]; then
 fi
 
 # Clean up on exit
-trap "{ rm -rf \"$PROFILE\"; }" EXIT
+trap "{ rm -rf \"$TEMPDIR\"; }" EXIT
 
 makePath FX_PROFILE "$PROFILE"
 MOZ_NO_REMOTE=1 NO_EM_RESTART=1 "$FX_EXECUTABLE" -profile "$FX_PROFILE" \
diff --git a/test/tests/zoteroTest.js b/test/tests/zoteroTest.js
index 0bd6289ce..8a8aad504 100644
--- a/test/tests/zoteroTest.js
+++ b/test/tests/zoteroTest.js
@@ -38,6 +38,8 @@ describe("Zotero Core Functions", function () {
 	});
 	
 	beforeEach(function* () {
+		// Trigger a call to setDataDirectory() now to avoid affecting the stub call count
+		Zotero.getZoteroDirectory();
 		stub1 = sinon.stub(Zotero, "setDataDirectory");
 	});