### Question:
GasUsageValidationRule implements DetachedBlockHeaderValidationRule { @Override public boolean validate(final BlockHeader header, final BlockHeader parent) { if (header.getGasUsed() > header.getGasLimit()) { LOG.trace( "Invalid block header: gas used {} exceeds gas limit {}", header.getGasUsed(), header.getGasLimit()); return false; } return true; }  @Override boolean validate(final BlockHeader header, final BlockHeader parent);  }### Answer:
@Test public void test() { final GasUsageValidationRule uut = new GasUsageValidationRule(); final BlockHeaderTestFixture blockBuilder = new BlockHeaderTestFixture(); blockBuilder.gasLimit(gasLimit); blockBuilder.gasUsed(gasUsed); final BlockHeader header = blockBuilder.buildHeader(); assertThat(uut.validate(header, null)).isEqualTo(expectedResult); }