#1150 - Add Argon2 support

- Add argon2 implementation

- Extract argon2 library check to method on Argon 2
- Add link to Wiki page on errors
- Check within Argon2Test if the test cases should be run, not in the abstract parent

src/test/java/fr/xephi/authme/security/HashAlgorithmIntegrationTest.java

@@ -2,6 +2,7 @@ package fr.xephi.authme.security;
 
 import ch.jalu.injector.Injector;
 import ch.jalu.injector.InjectorBuilder;
+import fr.xephi.authme.security.crypts.Argon2;
 import fr.xephi.authme.security.crypts.EncryptionMethod;
 import fr.xephi.authme.security.crypts.HashedPassword;
 import fr.xephi.authme.security.crypts.description.Recommendation;
@@ -61,6 +62,10 @@ public class HashAlgorithmIntegrationTest {
         // given / when / then
         for (HashAlgorithm algorithm : HashAlgorithm.values()) {
             if (!HashAlgorithm.CUSTOM.equals(algorithm) && !HashAlgorithm.PLAINTEXT.equals(algorithm)) {
+                if (HashAlgorithm.ARGON2.equals(algorithm) && !Argon2.isLibraryLoaded()) {
+                    System.out.println("[WARNING] Cannot find argon2 library, skipping integration test");
+                    continue;
+                }
                 EncryptionMethod method = injector.createIfHasDependencies(algorithm.getClazz());
                 if (method == null) {
                     fail("Could not create '" + algorithm.getClazz() + "' - forgot to provide some class?");

src/test/java/fr/xephi/authme/security/crypts/Argon2Test.java

@@ -0,0 +1,29 @@
+package fr.xephi.authme.security.crypts;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assume.assumeThat;
+
+/**
+ * Test for {@link Argon2}.
+ */
+public class Argon2Test extends AbstractEncryptionMethodTest {
+
+    private static final boolean IS_LIBRARY_LOADED = Argon2.isLibraryLoaded();
+
+    public Argon2Test() {
+        super(new Argon2(),
+            "$argon2i$v=19$m=65536,t=2,p=1$dOP8NiXsPTcMgzI4Z8Rbew$ShdowtoTEWTL5UTFz1UgQOigb9JOlm4ZxWPA6WbIeUw",  // password
+            "$argon2i$v=19$m=65536,t=2,p=1$amZHbPfgc5peKd/4w1AI1g$Q2PUiOVw47TACijP57U0xf7QfiZ00HV4eFzMDA6yKRE",  // PassWord1
+            "$argon2i$v=19$m=65536,t=2,p=1$58v7dWNn9/bpD00QLzSebw$7cMC7p0qceE3Mgf2yQp4X7c+UkO9oyJwQ7S6XTBubNs",  // &^%te$t?Pw@_
+            "$argon2i$v=19$m=65536,t=2,p=1$93OSU71DgBOzpmhti7+6rQ$sSSI6QQQdoG9DlGwLjYz576kTek89nwr9CyNpy6bsL0"); // âË_3(íù*
+
+        assumeThat("Argon2 library is not loaded - skipping test",
+            IS_LIBRARY_LOADED, equalTo(true));
+    }
+
+    @Override
+    protected boolean testHashEqualityForSameSalt() {
+        // Argon2 has a salt but it is handled internally
+        return false;
+    }
+}