2 files changed, 33 insertions, 4 deletions
diff --git a/chapter10/src/test/java/com/seaofnodes/simple/FuzzerWrap.java b/chapter10/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
index bb3bec1c..019140ad 100644
--- a/chapter10/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
+++ b/chapter10/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
@@ -8,15 +8,30 @@ import org.junit.Ignore;
 import static org.junit.Assert.assertTrue;
 
 /**
- * To use the fuzzer run the <code>fuzzPeeps</code> methods.
- * This can be done from IntelliJ Gui or remove the `@Ignore` annotation and start the test case from the command line
- * via <code>mvn clean test -Dtest=com.seaofnodes.simple.FuzzerWrap#fuzzPeeps</code>
+ * Normal tests run chapter-local regression seeds. Open failures and exploratory
+ * fuzzing are opt-in (run directly in the IDE or temporarily remove Ignore).
+ * Seeds depend on this chapter's generator; do not copy them between chapters.
  */
 public class FuzzerWrap {
 
+    private static final long[] REGRESSION_SEEDS = {
+    };
+
+    private static final long[] OPEN_FAILING_SEEDS = {
+    };
+
+    @Test         public void fuzzPeepsRegression  () { fuzzPeepsSeeds(REGRESSION_SEEDS); }
+    @Test @Ignore public void fuzzPeepsOpenFailures() { fuzzPeepsSeeds(OPEN_FAILING_SEEDS); }
+
+    private static void fuzzPeepsSeeds(long... seeds) {
+        var fuzzer = new Fuzzer();
+        for (long seed : seeds)
+            fuzzer.fuzzPeepsRegression(seed);
+    }
+
     @Test
     @Ignore
-    public void fuzzPeeps() {
+    public void fuzzPeepsLarge() {
         var fuzzer = new Fuzzer();
         for (int i=0; i<1000000; i++)
             fuzzer.fuzzPeeps(i);
diff --git a/chapter10/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java b/chapter10/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
index 51e39cd0..a82a7517 100644
--- a/chapter10/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
+++ b/chapter10/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
@@ -182,4 +182,18 @@ public class Fuzzer {
     public boolean noExceptions() {
         return exceptions.isEmpty();
     }
+
+    /** Run a fixed chapter-local seed without reducing or swallowing failures. */
+    public void fuzzPeepsRegression(long seed) {
+        var rand = new Random(seed);
+        var sb = new StringBuilder();
+        var valid = new ScriptGenerator(rand, sb, true).genProgram();
+        try {
+            runCheck(sb.toString(), valid);
+        } catch (Throwable e) {
+            AssertionError ae = new AssertionError("Fuzzer regression seed failed: " + seed);
+            ae.initCause(e);
+            throw ae;
+        }
+    }
 }