CASSANDRA-19975: to make MixedTopologyTest stable we need to know the…

… topology to make sure each change is safe

accord-core/src/test/java/accord/utils/Property.java

@@ -32,6 +32,7 @@
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeoutException;
+import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -212,9 +213,21 @@ private static String statefulPropertyError(StatefulBuilder input, Throwable cau
  String stateStr = state == null ? null : state.toString().replace("\n", "\n\t\t");
  sb.append("\tState: ").append(stateStr).append(": ").append(state == null ? "unknown type" : state.getClass().getCanonicalName()).append('\n');
  sb.append("\tHistory:").append('\n');
+ addList(sb, "\t\t", history);
+ return sb.toString();
+ }
+
+ private static void addList(StringBuilder sb, String prefix, List<String> list)
+ {
  int idx = 0;
- for (var event : history)
- sb.append("\t\t").append(++idx).append(": ").append(event).append('\n');
+ for (var event : list)
+ sb.append(prefix).append(++idx).append(": ").append(event).append('\n');
+ }
+
+ public static String formatList(String prefix, List<String> list)
+ {
+ StringBuilder sb = new StringBuilder();
+ addList(sb, prefix, list);
  return sb.toString();
  }
 
@@ -467,6 +480,7 @@ public <State, SystemUnderTest> void check(Commands<State, SystemUnderTest> comm
  }
  commands.destroySut(sut, null);
  commands.destroyState(state, null);
+ commands.onSuccess(state, sut, history);
  }
  catch (Throwable t)
  {
@@ -682,6 +696,7 @@ public interface Commands<State, SystemUnderTest>
  {
  Gen<State> genInitialState() throws Throwable;
  SystemUnderTest createSut(State state) throws Throwable;
+ default void onSuccess(State state, SystemUnderTest sut, List<String> history) throws Throwable {}
  default void destroyState(State state, @Nullable Throwable cause) throws Throwable {}
  default void destroySut(SystemUnderTest sut, @Nullable Throwable cause) throws Throwable {}
  Gen<Command<State, SystemUnderTest, ?>> commands(State state) throws Throwable;
@@ -697,6 +712,11 @@ public static <State> CommandsBuilder<State, Void> commands(Supplier<Gen<State>>
  return new CommandsBuilder<>(stateGen, ignore -> null);
  }
 
+ public interface StatefulSuccess<State, SystemUnderTest>
+ {
+ void apply(State state, SystemUnderTest sut, List<String> history) throws Throwable;
+ }
+
  public static class CommandsBuilder<State, SystemUnderTest>
  {
  public interface Setup<State, SystemUnderTest>
@@ -717,6 +737,9 @@ public interface Setup<State, SystemUnderTest>
  private FailingBiConsumer<State, Throwable> destroyState = null;
  @Nullable
  private FailingBiConsumer<SystemUnderTest, Throwable> destroySut = null;
+ @Nullable
+ private BiFunction<State, Gen<Command<State, SystemUnderTest, ?>>, Gen<Command<State, SystemUnderTest, ?>>> commandsTransformer = null;
+ private final List<StatefulSuccess<State, SystemUnderTest>> onSuccess = new ArrayList<>();
 
  public CommandsBuilder(Supplier<Gen<State>> stateGen, Function<State, SystemUnderTest> sutFactory)
  {
@@ -837,6 +860,18 @@ public CommandsBuilder<State, SystemUnderTest> unknownWeight(Gen.IntGen unknownW
  return this;
  }
 
+ public CommandsBuilder<State, SystemUnderTest> commandsTransformer(BiFunction<State, Gen<Command<State, SystemUnderTest, ?>>, Gen<Command<State, SystemUnderTest, ?>>> commandsTransformer)
+ {
+ this.commandsTransformer = commandsTransformer;
+ return this;
+ }
+
+ public CommandsBuilder<State, SystemUnderTest> onSuccess(StatefulSuccess<State, SystemUnderTest> fn)
+ {
+ onSuccess.add(fn);
+ return this;
+ }
+
  public Commands<State, SystemUnderTest> build()
  {
  Gen<Setup<State, SystemUnderTest>> commandsGen;
@@ -917,7 +952,8 @@ public SystemUnderTest createSut(State state) throws Throwable
  {
  if (preCommands != null)
  preCommands.accept(state);
- return commandsGen.map((rs, setup) -> setup.setup(rs, state));
+ Gen<Command<State, SystemUnderTest, ?>> map = commandsGen.map((rs, setup) -> setup.setup(rs, state));
+ return commandsTransformer == null ? map : commandsTransformer.apply(state, map);
  }
 
  @Override
@@ -934,6 +970,13 @@ public void destroySut(SystemUnderTest sut, @Nullable Throwable cause) throws Th
  if (destroySut != null)
  destroySut.accept(sut, cause);
  }
+
+ @Override
+ public void onSuccess(State state, SystemUnderTest sut, List<String> history) throws Throwable
+ {
+ for (var fn : onSuccess)
+ fn.apply(state, sut, history);
+ }
  };
  }