### Question:
FingerprintMixer { long getMultiplicand() { return mMultiplicand; } FingerprintMixer(SecretKey secretKey, byte[] salt);  static final int SALT_LENGTH_BYTES; }### Answer:
@Test public void getMultiplicand_withDifferentKey_returnsDifferentResult() throws Exception { int iterations = 100_000; HashSet<Long> returnedMultiplicands = new HashSet<>(); byte[] salt = randomSalt(); for (int i = 0; i < iterations; i++) { FingerprintMixer fingerprintMixer = new FingerprintMixer(randomKey(), salt); long multiplicand = fingerprintMixer.getMultiplicand(); returnedMultiplicands.add(multiplicand); } assertThat(returnedMultiplicands).containsNoDuplicates(); }
@Test public void getMultiplicand_isOdd() throws Exception { int iterations = 100_000; for (int i = 0; i < iterations; i++) { FingerprintMixer fingerprintMixer = new FingerprintMixer(randomKey(), randomSalt()); long multiplicand = fingerprintMixer.getMultiplicand(); assertThat(isOdd(multiplicand)).isTrue(); } }