### Question:
CodeExpression implements Serializable { public Set<Variable.Key> dependsOn() { return depends; } private  CodeExpression(String expr, Code code); static synchronized CodeExpression valueOf(String expression, Code code); Code getCode(); boolean isJava(); String getExpr(); Set<Variable.Key> dependsOn(); EvalSpice.ParseException getParseException(); String getSpiceText(); String getHSpiceText(boolean inPar); String getVerilogText(); Object eval(); @Override int hashCode(); @Override boolean equals(Object o); @Override String toString(); void write(IdWriter writer); static CodeExpression read(IdReader reader); static void printStatistics(boolean verbose);  }### Answer:
@Test public void dependsOn() { System.out.println("dependsOn"); CodeExpression instance = CodeExpression.valueOf("@a", CodeExpression.Code.JAVA); Set<Key> expResult = Collections.singleton(Variable.newKey("ATTR_a")); Set<Key> result = instance.dependsOn(); assertEquals(expResult, result); }