Use java.time classes for stored verification code expiration; add tests.

service/src/test/java/org/whispersystems/textsecuregcm/auth/StoredVerificationCodeTest.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2013-2021 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.auth;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class StoredVerificationCodeTest {
+
+  @ParameterizedTest
+  @MethodSource
+  void isValid(final StoredVerificationCode storedVerificationCode, final String code, final Instant currentTime, final boolean expectValid) {
+    assertEquals(expectValid, storedVerificationCode.isValid(code, currentTime));
+  }
+
+  private static Stream<Arguments> isValid() {
+    final Instant now = Instant.now();
+
+    return Stream.of(
+        Arguments.of(new StoredVerificationCode("code", now.toEpochMilli(), null, null), "code", now, true),
+        Arguments.of(new StoredVerificationCode("code", now.toEpochMilli(), null, null), "incorrect", now, false),
+        Arguments.of(new StoredVerificationCode("code", now.toEpochMilli(), null, null), "code", now.plus(Duration.ofHours(1)), false),
+        Arguments.of(new StoredVerificationCode("", now.toEpochMilli(), null, null), "", now, false)
+    );
+  }
+}