jetCheck tests: don't spam to console

jetCheck/src/jetCheck/Iteration.java

@@ -101,13 +101,13 @@ class CheckSession<T> {
   final int iterationCount;
   final IntUnaryOperator sizeHintFun;
 
-  CheckSession(Generator<T> generator, Predicate<T> property, long globalSeed, int iterationCount, IntUnaryOperator sizeHintFun) {
+  CheckSession(Generator<T> generator, Predicate<T> property, long globalSeed, int iterationCount, IntUnaryOperator sizeHintFun, boolean silent) {
     this.generator = generator;
     this.property = property;
     this.globalSeed = globalSeed;
     this.iterationCount = iterationCount;
     this.sizeHintFun = sizeHintFun;
-    notifier = new StatusNotifier(iterationCount);
+    notifier = silent ? StatusNotifier.SILENT : new StatusNotifier(iterationCount);
   }
 
   Iteration<T> firstIteration() {

jetCheck/src/jetCheck/PropertyChecker.java

@@ -15,6 +15,7 @@ public class PropertyChecker<T> {
   private long globalSeed = new Random().nextLong();
   private IntUnaryOperator sizeHintFun = iteration -> (iteration - 1) % DEFAULT_MAX_SIZE_HINT + 1;
   private int iterationCount = 100;
+  private boolean silent;
 
   private PropertyChecker(Generator<T> generator) {
     this.generator = generator;
@@ -60,6 +61,15 @@ public class PropertyChecker<T> {
     return this;
   }
 
+  /**
+   * Suppresses all output during property check and shrinking
+   * @return this PropertyChecker
+   */
+  public PropertyChecker<T> silently() {
+    this.silent = true;
+    return this;
+  }
+
   /**
    * Checks the property within a single iteration by using specified seed and size hint. Useful to debug the test after it's failed.
    */
@@ -72,7 +82,7 @@ public class PropertyChecker<T> {
    * given number of times (see {@link #withIterationCount(int)}).
    */
   public void shouldHold(@NotNull Predicate<T> property) {
-    Iteration<T> iteration = new CheckSession<>(generator, property, globalSeed, iterationCount, sizeHintFun).firstIteration();
+    Iteration<T> iteration = new CheckSession<>(generator, property, globalSeed, iterationCount, sizeHintFun, silent).firstIteration();
     while (iteration != null) {
       iteration = iteration.performIteration();
     }

jetCheck/src/jetCheck/StatusNotifier.java

@@ -14,6 +14,17 @@ import java.util.Locale;
  */
 @SuppressWarnings("UseOfSystemOutOrSystemErr")
 class StatusNotifier {
+  static final StatusNotifier SILENT = new StatusNotifier(0) {
+    @Override
+    boolean shouldPrint() {
+      return false;
+    }
+
+    @Override
+    void counterExampleFound(Iteration<?> iteration) {
+    }
+  };
+  
   private final int iterationCount;
   private int currentIteration;
   private long lastPrinted = System.currentTimeMillis();
@@ -34,7 +45,7 @@ class StatusNotifier {
     System.err.println(formatCurrentTime() + ": failed on iteration " + currentIteration + " (" + iteration.printSeeds() + "), shrinking...");
   }
 
-  private boolean shouldPrint() {
+  boolean shouldPrint() {
     if (System.currentTimeMillis() - lastPrinted > 5_000) {
       lastPrinted = System.currentTimeMillis();
       return true;

jetCheck/test/jetCheck/PropertyCheckerTestCase.java

@@ -11,7 +11,7 @@ abstract class PropertyCheckerTestCase extends TestCase {
 
   protected <T> PropertyFalsified checkFails(PropertyChecker<T> checker, Predicate<T> predicate) {
     try {
-      checker.shouldHold(predicate);
+      checker.silently().shouldHold(predicate);
       throw new AssertionError("Can't falsify " + getName());
     }
     catch (PropertyFalsified e) {
@@ -28,9 +28,11 @@ abstract class PropertyCheckerTestCase extends TestCase {
     //noinspection unchecked
     PropertyFailure<T> failure = (PropertyFailure<T>)e.getFailure();
 
+    /*
     System.out.println(" " + getName());
     System.out.println("Value: " + e.getBreakingValue());
     System.out.println("Data: " + e.getData());
+    */
     assertEquals(minimizationSteps, failure.getTotalMinimizationExampleCount()); // to track if framework changes don't increase shrinking time significantly on average
     assertEquals(e.getBreakingValue(), generator.getGeneratorFunction().apply(e.getData()));
 

jetCheck/test/jetCheck/ShrinkTest.java

@@ -38,7 +38,7 @@ public class ShrinkTest extends PropertyCheckerTestCase {
     checkFalsified(gen, property, 0); // prove that it sometimes fails
     for (int i = 0; i < 1000; i++) {
       try {
-        PropertyChecker.forAll(gen).shouldHold(property);
+        PropertyChecker.forAll(gen).silently().shouldHold(property);
       }
       catch (PropertyFalsified e) {
         assertEquals("[]", e.getBreakingValue());