jetCheck: refresh iteration seed on each attempt, otherwise recheck won't work

jetCheck/intellij.tools.jetCheck.iml

@@ -10,5 +10,6 @@
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" scope="TEST" name="JUnit4" level="project" />
     <orderEntry type="module" module-name="intellij.platform.annotations.java5" />
+    <orderEntry type="module" module-name="intellij.platform.util" scope="RUNTIME" />
   </component>
 </module>

jetCheck/src/org/jetbrains/jetCheck/Iteration.java

@@ -23,23 +23,32 @@ class Iteration<T> {
   };
 
   final CheckSession<T> session;
-  final long iterationSeed;
+  long iterationSeed;
   final int sizeHint;
   final int iterationNumber;
+  private Random random;
 
   Iteration(CheckSession<T> session, long iterationSeed, int iterationNumber) {
     this.session = session;
-    this.iterationSeed = iterationSeed;
     this.sizeHint = session.sizeHintFun.applyAsInt(iterationNumber);
     this.iterationNumber = iterationNumber;
     if (sizeHint < 0) {
       throw new IllegalArgumentException("Size hint should be non-negative, found " + sizeHint);
     }
+    initSeed(iterationSeed);
+  }
+
+  private void initSeed(long seed) {
+    iterationSeed = seed;
+    random = new Random(seed);
   }
 
   @Nullable
-  private CounterExampleImpl<T> findCounterExample(Random random) {
+  private CounterExampleImpl<T> findCounterExample() {
     for (int i = 0; i < 100; i++) {
+      if (i > 0) {
+        initSeed(random.nextLong());
+      }
       StructureNode node = new StructureNode(new NodeId(session.generator));
       T value;
       try {
@@ -75,8 +84,7 @@ class Iteration<T> {
   Iteration<T> performIteration() {
     session.notifier.iterationStarted(iterationNumber);
 
-    Random random = new Random(iterationSeed);
-    CounterExampleImpl<T> example = findCounterExample(random);
+    CounterExampleImpl<T> example = findCounterExample();
     if (example != null) {
       session.notifier.counterExampleFound(this);
       throw new PropertyFalsified(new PropertyFailureImpl<>(example, this));

jetCheck/src/org/jetbrains/jetCheck/StructureNode.java

@@ -205,7 +205,7 @@ class StructureNode extends StructureElement {
 
   @Override
   public int hashCode() {
-    return children.hashCode();
+    return children.hashCode() * 3;
   }
 
   @Override

jetCheck/test/org/jetbrains/jetCheck/GeneratorTest.java

@@ -60,7 +60,7 @@ public class GeneratorTest extends PropertyCheckerTestCase {
   public void testSortedDoublesNonDescending() {
     PropertyFailure<List<Double>> failure = checkFalsified(listsOf(doubles()),
                                                            l -> isSorted(l.stream().sorted().collect(Collectors.toList())),
-                                                           41);
+                                                           23);
     assertEquals(2, failure.getMinimalCounterexample().getExampleValue().size());
   }
 

jetCheck/test/org/jetbrains/jetCheck/PropertyCheckerTestCase.java

@@ -27,7 +27,7 @@ abstract class PropertyCheckerTestCase extends TestCase {
   }
 
   protected <T> PropertyFailure<T> checkFalsified(Generator<T> generator, Predicate<T> predicate, int minimizationSteps) {
-    PropertyFalsified e = checkFails(forAllStable(generator), predicate);
+    PropertyFalsified e = checkFails(forAllStable(generator).withIterationCount(1000), predicate);
     //noinspection unchecked
     PropertyFailure<T> failure = (PropertyFailure<T>)e.getFailure();
 

jetCheck/test/org/jetbrains/jetCheck/ShrinkTest.java

@@ -21,7 +21,7 @@ public class ShrinkTest extends PropertyCheckerTestCase {
                      String s = l.toString();
                      return !"abcdefghijklmnopqrstuvwxyz()[]#!".chars().allMatch(c -> s.indexOf((char)c) >= 0);
                    },
-                   258);
+                   254);
   }
 
   public void testShrinkingNonEmptyList() {

jetCheck/test/org/jetbrains/jetCheck/StatefulGeneratorTest.java

@@ -29,7 +29,7 @@ public class StatefulGeneratorTest extends PropertyCheckerTestCase {
     });
     List<InsertChar> minCmds = checkGeneratesExample(gen,
                                                      cmds -> InsertChar.performOperations(cmds).contains("ab"),
-                                                     64);
+                                                     36);
     assertEquals(minCmds.toString(), 2, minCmds.size());
   }
 
@@ -37,7 +37,7 @@ public class StatefulGeneratorTest extends PropertyCheckerTestCase {
     Scenario minHistory = checkFalsified(ImperativeCommand.scenarios(() -> env -> {
       StringBuilder sb = new StringBuilder();
       env.executeCommands(withRecursion(insertStringCmd(sb), deleteStringCmd(sb), checkDoesNotContain(sb, "A")));
-    }), Scenario::ensureSuccessful, 42).getMinimalCounterexample().getExampleValue();
+    }), Scenario::ensureSuccessful, 33).getMinimalCounterexample().getExampleValue();
 
     assertEquals("commands:\n" +
                  "  insert A at 0\n" +
@@ -56,7 +56,7 @@ public class StatefulGeneratorTest extends PropertyCheckerTestCase {
       };
 
       env.executeCommands(withRecursion(insertStringCmd(sb), replace, deleteStringCmd(sb), checkDoesNotContain(sb, "A")));
-    }), Scenario::ensureSuccessful, 76).getMinimalCounterexample().getExampleValue();
+    }), Scenario::ensureSuccessful, 56).getMinimalCounterexample().getExampleValue();
 
     assertEquals("commands:\n" +
                  "  insert A at 0\n" +