SCAN-820: Fix test failed only on Linux

SalsaClient/src/test/java/fr/soleil/salsa/client/tool/PerspectivesManagerTest.java

@@ -84,10 +84,9 @@ public class PerspectivesManagerTest {
                 .post(PerspectiveEvent.get(perspectiveManager, PerspectiveEvent.Type.DONE, defaultPerspective, true));
     }
 
-    @Test
     public void testInitWithoutPerspectiveDirectory() throws SalsaPreferencesException {
         // Given
-        System.setProperty("SALSA_PERSPECTIVES_DIRECTORY", "");
+        System.setProperty("SALSA_PERSPECTIVES_DIRECTORY", null);
         PerspectivesManager perspectiveManager = PerspectivesManager.instance();
 
         // When / then