r1.setProperty("p2", "v2");
registry.put("/props/t1/r1", r1);
Resource r1e1 = registry.get("/props/t1/r1");
r1e1.setContent("r1 content");
r1e1.removeProperty("p1");
registry.put("/props/t1/r1", r1e1);
Resource r1e2 = registry.get("/props/t1/r1");
assertEquals("Property is not removed.", r1e2.getProperty("p1"), null);