### Question:
Context { public void removeVar(String var) { varMap.remove(var); } Context();  Context(Map<String, Object> varMap); Map<String, Object> toMap(); Object getVar(String name); void putVar(String name, Object value); void removeVar(String var); Config getConfig(); @Override String toString();  }### Answer:
@Test public void removeVar() { Context context = new Context(); context.putVar("col", 1); Map<String, Object> vars = context.toMap(); assertEquals(vars.get("col"), 1); context.removeVar("col"); vars = context.toMap(); assertFalse( vars.containsKey("col") ); }