### Question:
CreateVolumeOptions extends BaseEC2RequestOptions { public CreateVolumeOptions volumeType(String volumeType) { formParameters.put("VolumeType", checkNotNull(volumeType, "volumeType")); return this; }  CreateVolumeOptions withSize(int size); int getSize(); CreateVolumeOptions fromSnapshotId(String snapshotId); String getSnapshotId(); CreateVolumeOptions volumeType(String volumeType); String getVolumeType(); CreateVolumeOptions withIops(Integer iops); Integer getIops(); CreateVolumeOptions isEncrypted(boolean encrypted); boolean getEncrypted();  }### Answer:
@Test public void testVolumeType() { CreateVolumeOptions options = new CreateVolumeOptions(); options.volumeType("test"); assertEquals(options.buildFormParameters().get("VolumeType"), ImmutableList.of("test")); }
@Test public void testVolumeTypeStatic() { CreateVolumeOptions options = volumeType("test"); assertEquals(options.buildFormParameters().get("VolumeType"), ImmutableList.of("test")); }
@Test(expectedExceptions = NullPointerException.class) public void testVolmeTypeNPE() { volumeType(null); }