@Test
  public void testZTestUniformityFailsWithTooSmallMessage() {
    String msg =
        assertThrows(
                GeneralSecurityException.class,
                new ThrowingRunnable() {
                  @Override
                  public void run() throws Throwable {
                    byte[] allZeros = new byte[4];
                    TestUtil.ztestUniformString(allZeros);
                  }
                })
            .getMessage();
    assertThat(msg).contains("Use more bytes.");
  }
Tests some of the more complex functions from TestUtil.
java_src/src/test/java/com/google/crypto/tink/testing/TestUtilTest.java