### Question:
GenesisConfigFile { public Optional<String> getCoinbase() { return JsonUtil.getString(configRoot, "coinbase"); } private  GenesisConfigFile(final ObjectNode config); static GenesisConfigFile mainnet(); static ObjectNode mainnetJsonNode(); static GenesisConfigFile development(); static GenesisConfigFile fromConfig(final String jsonString); static GenesisConfigFile fromConfig(final ObjectNode config); GenesisConfigOptions getConfigOptions(); GenesisConfigOptions getConfigOptions(final Map<String, String> overrides); Stream<GenesisAllocation> streamAllocations(); String getParentHash(); String getDifficulty(); String getExtraData(); long getGasLimit(); String getMixHash(); String getNonce(); Optional<String> getCoinbase(); long getTimestamp(); List<Long> getForks(); static final GenesisConfigFile DEFAULT; }### Answer:
@Test public void shouldGetCoinbase() { assertThat(configWithProperty("coinbase", "abcd").getCoinbase()).contains("abcd"); }
@Test public void shouldReturnEmptyWhenCoinbaseNotSpecified() { assertThat(EMPTY_CONFIG.getCoinbase()).isEmpty(); }