Don't extend HmacOneTimePasswordGenerator in TimeBasedOneTimePasswordGenerator

Author: jchambers

src/main/java/com/eatthepath/otp/TimeBasedOneTimePasswordGenerator.java

@@ -35,7 +35,8 @@
  *
  * @author <a href="https://github.com/jchambers">Jon Chambers</a>
  */
-public class TimeBasedOneTimePasswordGenerator extends HmacOneTimePasswordGenerator {
+public class TimeBasedOneTimePasswordGenerator {
+    private final HmacOneTimePasswordGenerator hotp;
     private final Duration timeStep;
 
     /**
@@ -115,7 +116,7 @@ public TimeBasedOneTimePasswordGenerator(final Duration timeStep, final int pass
     public TimeBasedOneTimePasswordGenerator(final Duration timeStep, final int passwordLength, final String algorithm)
             throws NoSuchAlgorithmRuntimeException {
 
-        super(passwordLength, algorithm);
+        this.hotp = new HmacOneTimePasswordGenerator(passwordLength, algorithm);
         this.timeStep = timeStep;
     }
 
@@ -131,7 +132,7 @@ public TimeBasedOneTimePasswordGenerator(final Duration timeStep, final int pass
      * @throws InvalidKeyException if the given key is inappropriate for initializing the {@link Mac} for this generator
      */
     public int generateOneTimePassword(final Key key, final Instant timestamp) throws InvalidKeyException {
-        return this.generateOneTimePassword(key, timestamp.toEpochMilli() / this.timeStep.toMillis());
+        return this.hotp.generateOneTimePassword(key, timestamp.toEpochMilli() / this.timeStep.toMillis());
     }
 
     /**
@@ -163,7 +164,7 @@ public String generateOneTimePasswordString(final Key key, final Instant timesta
      * @throws InvalidKeyException if the given key is inappropriate for initializing the {@link Mac} for this generator
      */
     public String generateOneTimePasswordString(final Key key, final Instant timestamp, final Locale locale) throws InvalidKeyException {
-        return this.formatOneTimePassword(this.generateOneTimePassword(key, timestamp), locale);
+        return this.hotp.formatOneTimePassword(this.generateOneTimePassword(key, timestamp), locale);
     }
 
     /**
@@ -174,4 +175,22 @@ public String generateOneTimePasswordString(final Key key, final Instant timesta
     public Duration getTimeStep() {
         return this.timeStep;
     }
+
+    /**
+     * Returns the length, in decimal digits, of passwords produced by this generator.
+     *
+     * @return the length, in decimal digits, of passwords produced by this generator
+     */
+    public int getPasswordLength() {
+        return this.hotp.getPasswordLength();
+    }
+
+    /**
+     * Returns the name of the HMAC algorithm used by this generator.
+     *
+     * @return the name of the HMAC algorithm used by this generator
+     */
+    public String getAlgorithm() {
+        return this.hotp.getAlgorithm();
+    }
 }

src/test/java/com/eatthepath/otp/HmacOneTimePasswordGeneratorTest.java

@@ -76,7 +76,7 @@ void testGetAlgorithm() {
     @ParameterizedTest
     @MethodSource("argumentsForTestGenerateOneTimePasswordHotp")
     void testGenerateOneTimePassword(final int counter, final int expectedOneTimePassword) throws Exception {
-        assertEquals(expectedOneTimePassword, this.getDefaultGenerator().generateOneTimePassword(HOTP_KEY, counter));
+        assertEquals(expectedOneTimePassword, new HmacOneTimePasswordGenerator().generateOneTimePassword(HOTP_KEY, counter));
     }
 
     @Test
@@ -106,7 +106,7 @@ private static Stream<Arguments> argumentsForTestGenerateOneTimePasswordHotp() {
     @MethodSource("argumentsForTestGenerateOneTimePasswordStringHotp")
     void testGenerateOneTimePasswordString(final int counter, final String expectedOneTimePassword) throws Exception {
         Locale.setDefault(Locale.US);
-        assertEquals(expectedOneTimePassword, this.getDefaultGenerator().generateOneTimePasswordString(HOTP_KEY, counter));
+        assertEquals(expectedOneTimePassword, new HmacOneTimePasswordGenerator().generateOneTimePasswordString(HOTP_KEY, counter));
     }
 
     private static Stream<Arguments> argumentsForTestGenerateOneTimePasswordStringHotp() {
@@ -128,7 +128,7 @@ private static Stream<Arguments> argumentsForTestGenerateOneTimePasswordStringHo
     @MethodSource("argumentsForTestGenerateOneTimePasswordStringLocaleHotp")
     void testGenerateOneTimePasswordStringLocale(final int counter, final Locale locale, final String expectedOneTimePassword) throws Exception {
         Locale.setDefault(Locale.US);
-        assertEquals(expectedOneTimePassword, this.getDefaultGenerator().generateOneTimePasswordString(HOTP_KEY, counter, locale));
+        assertEquals(expectedOneTimePassword, new HmacOneTimePasswordGenerator().generateOneTimePasswordString(HOTP_KEY, counter, locale));
     }
 
     private static Stream<Arguments> argumentsForTestGenerateOneTimePasswordStringLocaleHotp() {
@@ -147,8 +147,4 @@ private static Stream<Arguments> argumentsForTestGenerateOneTimePasswordStringLo
                 arguments(9, locale, "५२०४८९")
         );
     }
-
-    protected HmacOneTimePasswordGenerator getDefaultGenerator() {
-        return new HmacOneTimePasswordGenerator();
-    }
 }

src/test/java/com/eatthepath/otp/TimeBasedOneTimePasswordGeneratorTest.java

@@ -36,7 +36,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.params.provider.Arguments.arguments;
 
-public class TimeBasedOneTimePasswordGeneratorTest extends HmacOneTimePasswordGeneratorTest {
+public class TimeBasedOneTimePasswordGeneratorTest {
 
     private static final String HMAC_SHA1_ALGORITHM = "HmacSHA1";
     private static final String HMAC_SHA256_ALGORITHM = "HmacSHA256";
@@ -54,17 +54,22 @@ public class TimeBasedOneTimePasswordGeneratorTest extends HmacOneTimePasswordGe
             new SecretKeySpec("1234567890123456789012345678901234567890123456789012345678901234".getBytes(StandardCharsets.US_ASCII),
                     TimeBasedOneTimePasswordGenerator.TOTP_ALGORITHM_HMAC_SHA512);
 
-    @Override
-    protected HmacOneTimePasswordGenerator getDefaultGenerator() {
-        return new TimeBasedOneTimePasswordGenerator();
+    @Test
+    void testGetPasswordLength() {
+        final int passwordLength = 7;
+        assertEquals(passwordLength, new TimeBasedOneTimePasswordGenerator(Duration.ofSeconds(30), passwordLength).getPasswordLength());
+    }
+
+    @Test
+    void testGetAlgorithm() {
+        final String algorithm = TimeBasedOneTimePasswordGenerator.TOTP_ALGORITHM_HMAC_SHA256;
+        assertEquals(algorithm, new TimeBasedOneTimePasswordGenerator(Duration.ofSeconds(30), 6, algorithm).getAlgorithm());
     }
 
     @Test
     void testGetTimeStep() {
         final Duration timeStep = Duration.ofSeconds(97);
-        final TimeBasedOneTimePasswordGenerator totp = new TimeBasedOneTimePasswordGenerator(timeStep);
-
-        assertEquals(timeStep, totp.getTimeStep());
+        assertEquals(timeStep, new TimeBasedOneTimePasswordGenerator(timeStep).getTimeStep());
     }
 
     /**