Streamline random generation

testng-core/src/test/java/test/dataprovider/issue3081/TestClassSample.java

@@ -1,18 +1,16 @@
 package test.dataprovider.issue3081;
 
-import java.security.SecureRandom;
 import java.util.Collections;
-import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.IntStream;
 import org.testng.annotations.DataProvider;
 import org.testng.annotations.Test;
+import test.support.SafeRandoms;
 
 public class TestClassSample {
   private static final Set<Long> logs = ConcurrentHashMap.newKeySet();
-  private static final Random random = new SecureRandom();
 
   public static Set<Long> getLogs() {
     return Collections.unmodifiableSet(logs);
@@ -30,7 +28,7 @@ public static Object[] parallelDpStrings() {
   @Test(dataProvider = "parallelDpStrings")
   public void testStrings(String ignored) throws InterruptedException {
     print();
-    TimeUnit.MILLISECONDS.sleep(random.nextInt(500));
+    TimeUnit.MILLISECONDS.sleep(SafeRandoms.nextInt(200, 300));
   }
 
   private static void print() {

testng-core/src/test/java/test/dataprovider/issue3081/TestClassWithPrioritiesSample.java

@@ -1,18 +1,16 @@
 package test.dataprovider.issue3081;
 
-import java.security.SecureRandom;
 import java.util.Collections;
-import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.IntStream;
 import org.testng.annotations.DataProvider;
 import org.testng.annotations.Test;
+import test.support.SafeRandoms;
 
 public class TestClassWithPrioritiesSample {
   private static final Set<Long> logs = ConcurrentHashMap.newKeySet();
-  private static final Random random = new SecureRandom();
 
   public static Set<Long> getLogs() {
     return Collections.unmodifiableSet(logs);
@@ -30,7 +28,7 @@ public static Object[] parallelDpStrings() {
   @Test(dataProvider = "parallelDpStrings", priority = 1)
   public void testStrings(String ignored) throws InterruptedException {
     print();
-    TimeUnit.MILLISECONDS.sleep(random.nextInt(500));
+    TimeUnit.MILLISECONDS.sleep(SafeRandoms.nextInt(200, 300));
   }
 
   @Test(priority = 2)

testng-core/src/test/java/test/factory/issue326/SampleTestClass.java

@@ -3,13 +3,13 @@
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
-import java.util.Random;
 import java.util.concurrent.TimeUnit;
 import org.testng.ITestResult;
 import org.testng.Reporter;
 import org.testng.annotations.DataProvider;
 import org.testng.annotations.Factory;
 import org.testng.annotations.Test;
+import test.support.SafeRandoms;
 
 public class SampleTestClass {
 
@@ -18,12 +18,10 @@ public class SampleTestClass {
   static final String BARNEY = "Barney";
 
   private final String instance;
-  private final Random random;
 
   @Factory(dataProvider = "dp")
   public SampleTestClass(String instance) {
     this.instance = instance;
-    random = new Random();
   }
 
   @DataProvider
@@ -50,6 +48,6 @@ public String toString() {
   private void printer() throws InterruptedException {
     ITestResult result = Reporter.getCurrentTestResult();
     result.setAttribute(THREAD_ID, Thread.currentThread().getId());
-    TimeUnit.MILLISECONDS.sleep(10 * random.nextInt(100));
+    TimeUnit.MILLISECONDS.sleep(10L * SafeRandoms.nextInt(30, 70));
   }
 }

testng-core/src/test/java/test/support/SafeRandoms.java

@@ -0,0 +1,39 @@
+package test.support;
+
+import static org.assertj.core.util.Preconditions.checkArgument;
+
+import java.util.Objects;
+import java.util.Random;
+
+public final class SafeRandoms {
+
+  private static final Random random = new Random();
+
+  private SafeRandoms() {}
+
+  /**
+   * @param delta - Represents a constant that should be added to the generated random value. This
+   *     will ensure that there are no zero values generated.
+   * @param upperBound - The upper bound (exclusive). Must be positive.
+   * @return - A random number which is a summation of the delta and the actual random value that is
+   *     lesser than the upperBound value.
+   */
+  public static int nextInt(int delta, int upperBound) {
+    return nextInt(delta, upperBound, random);
+  }
+
+  /**
+   * @param delta - Represents a constant that should be added to the generated random value. This
+   *     will ensure that there are no zero values generated.
+   * @param upperBound - The upper bound (exclusive). Must be positive.
+   * @param random - An existing instance of {@link Random} to be used.
+   * @return - A random number which is a summation of the delta and the actual random value that is
+   *     lesser than the upperBound value.
+   */
+  public static int nextInt(int delta, int upperBound, Random random) {
+    checkArgument(delta >= 0, "Delta should be non-zero");
+    checkArgument(upperBound >= 0, "Upper bound should be non-zero");
+    checkArgument(delta < upperBound, "Delta should be less than Upper bound");
+    return delta + Objects.requireNonNull(random).nextInt(upperBound);
+  }
+}

testng-core/src/test/java/test/thread/TrueParallelSampleTest.java

@@ -2,6 +2,7 @@
 
 import java.util.Random;
 import org.testng.annotations.Test;
+import test.support.SafeRandoms;
 
 @Test
 public class TrueParallelSampleTest extends BaseThreadTest {
@@ -10,7 +11,7 @@ public class TrueParallelSampleTest extends BaseThreadTest {
   private void log(String s) {
     logString(s);
     try {
-      Thread.sleep(random.nextInt(10));
+      Thread.sleep(SafeRandoms.nextInt(3, 7, random));
     } catch (InterruptedException ex) {
       Thread.yield();
     }

testng-core/src/test/java/test/thread/issue188/Issue188TestSample.java

@@ -1,18 +1,17 @@
 package test.thread.issue188;
 
 import java.util.Map;
-import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import org.testng.ITestResult;
 import org.testng.Reporter;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
+import test.support.SafeRandoms;
 
 public class Issue188TestSample {
   public static final Map<Long, Set<String>> timestamps = new ConcurrentHashMap<>();
-  private static final Random random = new Random();
 
   @BeforeMethod
   public void logTime(ITestResult itr) {
@@ -37,17 +36,9 @@ public void anotherSampleTest() {
 
   private void sleepSilently() {
     try {
-      TimeUnit.MILLISECONDS.sleep(500 * random());
+      TimeUnit.MILLISECONDS.sleep(500L * SafeRandoms.nextInt(1, 10));
     } catch (InterruptedException e) {
       Thread.currentThread().interrupt();
     }
   }
-
-  private static long random() {
-    int value = random.nextInt(10);
-    if (value == 0) {
-      return 1;
-    }
-    return value;
-  }
 }