Fix some time sensitive tests

Some test were failing since last June, because some notOnOrAfter saml
node expired.
Since the library use Joda Time for these check, we can use the
DateTimeUtils.setCurrentMillisFixed utility to make them pass.

Author: Corentin Groix

core/src/test/java/com/onelogin/saml2/test/authn/AuthnResponseTest.java

@@ -12,7 +12,12 @@
 import com.onelogin.saml2.util.Util;
 
 import org.hamcrest.Matchers;
+import org.joda.time.DateTime;
+import org.joda.time.DateTimeUtils;
 import org.joda.time.Instant;
+import org.joda.time.format.ISODateTimeFormat;
+import org.junit.After;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -23,6 +28,7 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
@@ -50,6 +56,18 @@ public class AuthnResponseTest {
 	@Rule
 	public ExpectedException expectedEx = ExpectedException.none();
 
+	@Before
+	public void setDateTime() {
+		//All calls to Joda time check will use this timestamp as "now" value : 
+		setDateTime("2020-06-01T00:00:00Z");
+	}
+	
+	@After
+	public void goBackToNormal() {
+		DateTimeUtils.setCurrentMillisSystem();
+	}
+
+	
 	/**
 	 * Tests the constructor of SamlResponse
 	 *
@@ -2678,5 +2696,10 @@ private static HttpRequest newHttpRequest(String samlResponseEncoded) {
 	private static HttpRequest newHttpRequest(String requestURL, String samlResponseEncoded) {
 		return new HttpRequest(requestURL).addParameter("SAMLResponse", samlResponseEncoded);
 	}
+	
+	private void setDateTime(String ISOTimeStamp) {
+		DateTime dateTime = ISODateTimeFormat.dateTimeNoMillis().withZoneUTC().parseDateTime(ISOTimeStamp);
+		DateTimeUtils.setCurrentMillisFixed(dateTime.toDate().getTime());
+	}
 }