test SecureRandom properties

Author: TilmanNeumann

src/test/java/de/tilman_neumann/jml/random/SecureRandomTest.java

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+/*
+ * java-math-library is a Java library focused on number theory, but not necessarily limited to it. It is based on the PSIQS 4.0 factoring project.
+ * Copyright (C) 2018-2025 Tilman Neumann - tilman.neumann@web.de
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with this program;
+ * if not, see <http://www.gnu.org/licenses/>.
+ */
+package de.tilman_neumann.jml.random;
+
+import java.security.SecureRandom;
+import java.util.ArrayList;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import de.tilman_neumann.util.ConfigUtil;
+
+import static org.junit.Assert.assertNotEquals;
+
+public class SecureRandomTest {
+
+	@BeforeClass
+	public static void setup() {
+		ConfigUtil.initProject();
+	}
+	
+	@Test
+	public void secureRandomSequenceIsNotReproducible() {
+		SecureRandom secureRandom = new SecureRandom();
+		long seed = 2487568097L;
+		
+		secureRandom.setSeed(seed);
+		ArrayList<Integer> secureList1 = new ArrayList<>();
+		for (int n=0; n<20; n++) {
+			secureList1.add(secureRandom.nextInt());
+		}
+
+		secureRandom.setSeed(seed);
+		ArrayList<Integer> secureList2 = new ArrayList<>();
+		for (int n=0; n<20; n++) {
+			secureList2.add(secureRandom.nextInt());
+		}
+		assertNotEquals(secureList1, secureList2);
+	}
+}