### Question:
Ed25519FieldElement implements Serializable { public boolean isNonZero() { return this.encode().isNonZero(); } Ed25519FieldElement(final int[] values); static Ed25519FieldElement sqrt(final Ed25519FieldElement u, final Ed25519FieldElement v); int[] getRaw(); boolean isNonZero(); Ed25519FieldElement add(final Ed25519FieldElement g); Ed25519FieldElement subtract(final Ed25519FieldElement g); Ed25519FieldElement negate(); Ed25519FieldElement multiply(final Ed25519FieldElement g); Ed25519FieldElement square(); Ed25519FieldElement squareAndDouble(); Ed25519FieldElement invert(); Ed25519EncodedFieldElement encode(); boolean isNegative(); @Override int hashCode(); @Override boolean equals(final Object obj); @Override String toString();  }### Answer:
@Test public void isNonZeroReturnsFalseIfFieldElementIsZero() { final Ed25519FieldElement f = new Ed25519FieldElement(new int[10]); MatcherAssert.assertThat(f.isNonZero(), IsEqual.equalTo(false)); }
@Test public void isNonZeroReturnsTrueIfFieldElementIsNonZero() { final int[] t = new int[10]; t[0] = 5; final Ed25519FieldElement f = new Ed25519FieldElement(t); MatcherAssert.assertThat(f.isNonZero(), IsEqual.equalTo(true)); }