LUCENE-9350: Don't hold references to large automata on FuzzyQuery (#1467)

LUCENE-9068 moved fuzzy automata construction into FuzzyQuery itself. However,
this has the nasty side-effect of blowing up query caches that expect queries to be
fairly small. This commit restores the previous behaviour of caching the large automata
on an AttributeSource shared between segments, while making the construction a
bit clearer by factoring it out into a package-private FuzzyAutomatonBuilder.

lucene/core/src/java/org/apache/lucene/search/FuzzyAutomatonBuilder.java

@@ -0,0 +1,88 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.lucene.search;
+
+import org.apache.lucene.util.UnicodeUtil;
+import org.apache.lucene.util.automaton.CompiledAutomaton;
+import org.apache.lucene.util.automaton.LevenshteinAutomata;
+import org.apache.lucene.util.automaton.TooComplexToDeterminizeException;
+
+/**
+ * Builds a set of CompiledAutomaton for fuzzy matching on a given term,
+ * with specified maximum edit distance, fixed prefix and whether or not
+ * to allow transpositions.
+ */
+class FuzzyAutomatonBuilder {
+
+  private final String term;
+  private final int maxEdits;
+  private final LevenshteinAutomata levBuilder;
+  private final String prefix;
+  private final int termLength;
+
+  FuzzyAutomatonBuilder(String term, int maxEdits, int prefixLength, boolean transpositions) {
+    if (maxEdits < 0 || maxEdits > LevenshteinAutomata.MAXIMUM_SUPPORTED_DISTANCE) {
+      throw new IllegalArgumentException("max edits must be 0.." + LevenshteinAutomata.MAXIMUM_SUPPORTED_DISTANCE + ", inclusive; got: " + maxEdits);
+    }
+    if (prefixLength < 0) {
+      throw new IllegalArgumentException("prefixLength cannot be less than 0");
+    }
+    this.term = term;
+    this.maxEdits = maxEdits;
+    int[] codePoints = stringToUTF32(term);
+    this.termLength = codePoints.length;
+    prefixLength = Math.min(prefixLength, codePoints.length);
+    int[] suffix = new int[codePoints.length - prefixLength];
+    System.arraycopy(codePoints, prefixLength, suffix, 0, suffix.length);
+    this.levBuilder = new LevenshteinAutomata(suffix, Character.MAX_CODE_POINT, transpositions);
+    this.prefix = UnicodeUtil.newString(codePoints, 0, prefixLength);
+  }
+
+  CompiledAutomaton[] buildAutomatonSet() {
+    CompiledAutomaton[] compiled = new CompiledAutomaton[maxEdits + 1];
+    for (int i = 0; i <= maxEdits; i++) {
+      try {
+        compiled[i] = new CompiledAutomaton(levBuilder.toAutomaton(i, prefix), true, false);
+      }
+      catch (TooComplexToDeterminizeException e) {
+        throw new FuzzyTermsEnum.FuzzyTermsException(term, e);
+      }
+    }
+    return compiled;
+  }
+
+  CompiledAutomaton buildMaxEditAutomaton() {
+    try {
+      return new CompiledAutomaton(levBuilder.toAutomaton(maxEdits, prefix), true, false);
+    } catch (TooComplexToDeterminizeException e) {
+      throw new FuzzyTermsEnum.FuzzyTermsException(term, e);
+    }
+  }
+
+  int getTermLength() {
+    return this.termLength;
+  }
+
+  private static int[] stringToUTF32(String text) {
+    int[] termText = new int[text.codePointCount(0, text.length())];
+    for (int cp, i = 0, j = 0; i < text.length(); i += Character.charCount(cp)) {
+      termText[j++] = cp = text.codePointAt(i);
+    }
+    return termText;
+  }
+}

lucene/core/src/java/org/apache/lucene/search/FuzzyQuery.java

@@ -18,14 +18,13 @@ package org.apache.lucene.search;
 
 
 import java.io.IOException;
+import java.util.Objects;
 
 import org.apache.lucene.index.SingleTermsEnum;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
-import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.AttributeSource;
-import org.apache.lucene.util.RamUsageEstimator;
 import org.apache.lucene.util.automaton.CompiledAutomaton;
 import org.apache.lucene.util.automaton.LevenshteinAutomata;
 
@@ -53,9 +52,7 @@ import org.apache.lucene.util.automaton.LevenshteinAutomata;
  * not match an indexed term "ab", and FuzzyQuery on term "a" with maxEdits=2 will not
  * match an indexed term "abc".
  */
-public class FuzzyQuery extends MultiTermQuery implements Accountable {
+public class FuzzyQuery extends MultiTermQuery {
-
-  private static final long BASE_RAM_BYTES = RamUsageEstimator.shallowSizeOfInstance(AutomatonQuery.class);
   
   public final static int defaultMaxEdits = LevenshteinAutomata.MAXIMUM_SUPPORTED_DISTANCE;
   public final static int defaultPrefixLength = 0;
@@ -67,10 +64,6 @@ public class FuzzyQuery extends MultiTermQuery implements Accountable {
   private final boolean transpositions;
   private final int prefixLength;
   private final Term term;
-  private final int termLength;
-  private final CompiledAutomaton[] automata;
-
-  private final long ramBytesUsed;
   
   /**
    * Create a new FuzzyQuery that will match terms with an edit distance 
@@ -106,22 +99,7 @@ public class FuzzyQuery extends MultiTermQuery implements Accountable {
     this.prefixLength = prefixLength;
     this.transpositions = transpositions;
     this.maxExpansions = maxExpansions;
-    int[] codePoints = FuzzyTermsEnum.stringToUTF32(term.text());
-    this.termLength = codePoints.length;
-    this.automata = FuzzyTermsEnum.buildAutomata(term.text(), codePoints, prefixLength, transpositions, maxEdits);
     setRewriteMethod(new MultiTermQuery.TopTermsBlendedFreqScoringRewrite(maxExpansions));
-    this.ramBytesUsed = calculateRamBytesUsed(term, this.automata);
-  }
-
-  private static long calculateRamBytesUsed(Term term, CompiledAutomaton[] automata) {
-    long bytes = BASE_RAM_BYTES + term.ramBytesUsed();
-    for (CompiledAutomaton a : automata) {
-      bytes += a.ramBytesUsed();
-    }
-    bytes += 4 * Integer.BYTES;
-    bytes += Long.BYTES;
-    bytes += 1;
-    return bytes;
   }
   
   /**
@@ -173,8 +151,9 @@ public class FuzzyQuery extends MultiTermQuery implements Accountable {
   /**
    * Returns the compiled automata used to match terms
    */
-  public CompiledAutomaton[] getAutomata() {
+  public CompiledAutomaton getAutomata() {
-    return automata;
+    FuzzyAutomatonBuilder builder = new FuzzyAutomatonBuilder(term.text(), maxEdits, prefixLength, transpositions);
+    return builder.buildMaxEditAutomaton();
   }
 
   @Override
@@ -183,7 +162,7 @@ public class FuzzyQuery extends MultiTermQuery implements Accountable {
       if (maxEdits == 0 || prefixLength >= term.text().length()) {
         visitor.consumeTerms(this, term);
       } else {
-        automata[automata.length - 1].visit(visitor, this, field);
+        visitor.consumeTermsMatching(this, term.field(), () -> getAutomata().runAutomaton);
       }
     }
   }
@@ -193,7 +172,7 @@ public class FuzzyQuery extends MultiTermQuery implements Accountable {
     if (maxEdits == 0 || prefixLength >= term.text().length()) {  // can only match if it's exact
       return new SingleTermsEnum(terms.iterator(), term.bytes());
     }
-    return new FuzzyTermsEnum(terms, atts, getTerm(), termLength, maxEdits, automata);
+    return new FuzzyTermsEnum(terms, atts, getTerm(), maxEdits, prefixLength, transpositions);
   }
 
   /**
@@ -237,22 +216,9 @@ public class FuzzyQuery extends MultiTermQuery implements Accountable {
     if (getClass() != obj.getClass())
       return false;
     FuzzyQuery other = (FuzzyQuery) obj;
-    // Note that we don't need to compare termLength or automata because they
+    return Objects.equals(maxEdits, other.maxEdits) && Objects.equals(prefixLength, other.prefixLength)
-    // are entirely determined by the other fields
+        && Objects.equals(maxExpansions, other.maxExpansions) && Objects.equals(transpositions, other.transpositions)
-    if (maxEdits != other.maxEdits)
+        && Objects.equals(term, other.term);
-      return false;
-    if (prefixLength != other.prefixLength)
-      return false;
-    if (maxExpansions != other.maxExpansions)
-      return false;
-    if (transpositions != other.transpositions)
-      return false;
-    if (term == null) {
-      if (other.term != null)
-        return false;
-    } else if (!term.equals(other.term))
-      return false;
-    return true;
   }
 
   /**
@@ -274,8 +240,4 @@ public class FuzzyQuery extends MultiTermQuery implements Accountable {
     }
   }
 
-  @Override
-  public long ramBytesUsed() {
-    return ramBytesUsed;
-  }
 }

lucene/core/src/java/org/apache/lucene/search/FuzzyTermsEnum.java

@@ -18,6 +18,7 @@ package org.apache.lucene.search;
 
 
 import java.io.IOException;
+import java.util.function.Supplier;
 
 import org.apache.lucene.index.ImpactsEnum;
 import org.apache.lucene.index.PostingsEnum;
@@ -25,14 +26,14 @@ import org.apache.lucene.index.Term;
 import org.apache.lucene.index.TermState;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
+import org.apache.lucene.util.Attribute;
+import org.apache.lucene.util.AttributeImpl;
+import org.apache.lucene.util.AttributeReflector;
 import org.apache.lucene.util.AttributeSource;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
 import org.apache.lucene.util.UnicodeUtil;
-import org.apache.lucene.util.automaton.Automaton;
 import org.apache.lucene.util.automaton.CompiledAutomaton;
-import org.apache.lucene.util.automaton.LevenshteinAutomata;
-import org.apache.lucene.util.automaton.TooComplexToDeterminizeException;
 
 /** Subclass of TermsEnum for enumerating all terms that are similar
  * to the specified filter term.
@@ -57,21 +58,21 @@ public final class FuzzyTermsEnum extends TermsEnum {
   private final MaxNonCompetitiveBoostAttribute maxBoostAtt;
 
   private final CompiledAutomaton[] automata;
+  private final Terms terms;
+  private final int termLength;
+  private final Term term;
   
   private float bottom;
   private BytesRef bottomTerm;
 
   private BytesRef queuedBottom;
 
-  private final int termLength;
 
   // Maximum number of edits we will accept.  This is either 2 or 1 (or, degenerately, 0) passed by the user originally,
   // but as we collect terms, we can lower this (e.g. from 2 to 1) if we detect that the term queue is full, and all
   // collected terms are ed=1:
   private int maxEdits;
 
-  private final Terms terms;
-  private final Term term;
 
   /**
    * Constructor for enumeration of all terms from specified <code>reader</code> which share a prefix of
@@ -88,43 +89,44 @@ public final class FuzzyTermsEnum extends TermsEnum {
    * @throws IOException if there is a low-level IO error
    */
   public FuzzyTermsEnum(Terms terms, Term term, int maxEdits, int prefixLength, boolean transpositions) throws IOException {
-    this(terms, term, stringToUTF32(term.text()), maxEdits, prefixLength, transpositions);
+    this(terms, new AttributeSource(), term, () -> new FuzzyAutomatonBuilder(term.text(), maxEdits, prefixLength, transpositions));
-  }
-
-  private FuzzyTermsEnum(Terms terms, Term term, int[] codePoints, int maxEdits, int prefixLength, boolean transpositions) throws IOException {
-    this(terms, new AttributeSource(), term, codePoints.length, maxEdits,
-        buildAutomata(term.text(), codePoints, prefixLength, transpositions, maxEdits));
   }
 
   /**
    * Constructor for enumeration of all terms from specified <code>reader</code> which share a prefix of
    * length <code>prefixLength</code> with <code>term</code> and which have at most {@code maxEdits} edits.
    * <p>
-   * After calling the constructor the enumeration is already pointing to the first 
+   * After calling the constructor the enumeration is already pointing to the first
-   * valid term if such a term exists. 
+   * valid term if such a term exists.
-   * 
+   *
    * @param terms Delivers terms.
-   * @param atts {@link AttributeSource} created by the rewrite method of {@link MultiTermQuery}
+   * @param atts An AttributeSource used to share automata between segments
-   *              that contains information about competitive boosts during rewrite
    * @param term Pattern term.
    * @param maxEdits Maximum edit distance.
-   * @param automata An array of levenshtein automata to match against terms,
+   * @param prefixLength the length of the required common prefix
-   *                 see {@link #buildAutomata(String, int[], int, boolean, int)}
+   * @param transpositions whether transpositions should count as a single edit
    * @throws IOException if there is a low-level IO error
    */
-  public FuzzyTermsEnum(Terms terms, AttributeSource atts, Term term, int termLength,
+  FuzzyTermsEnum(Terms terms, AttributeSource atts, Term term, int maxEdits, int prefixLength, boolean transpositions) throws IOException {
-      final int maxEdits, CompiledAutomaton[] automata) throws IOException {
+    this(terms, atts, term, () -> new FuzzyAutomatonBuilder(term.text(), maxEdits, prefixLength, transpositions));
+  }
+
+  private FuzzyTermsEnum(Terms terms, AttributeSource atts, Term term, Supplier<FuzzyAutomatonBuilder> automatonBuilder) throws IOException {
 
-    this.maxEdits = maxEdits;
     this.terms = terms;
-    this.term = term;
     this.atts = atts;
-    this.termLength = termLength;
+    this.term = term;
 
     this.maxBoostAtt = atts.addAttribute(MaxNonCompetitiveBoostAttribute.class);
     this.boostAtt = atts.addAttribute(BoostAttribute.class);
 
-    this.automata = automata;
+    atts.addAttributeImpl(new AutomatonAttributeImpl());
+    AutomatonAttribute aa = atts.addAttribute(AutomatonAttribute.class);
+    aa.init(automatonBuilder);
+
+    this.automata = aa.getAutomata();
+    this.termLength = aa.getTermLength();
+    this.maxEdits = this.automata.length - 1;
 
     bottom = maxBoostAtt.getMaxNonCompetitiveBoost();
     bottomTerm = maxBoostAtt.getCompetitiveTerm();
@@ -145,47 +147,6 @@ public final class FuzzyTermsEnum extends TermsEnum {
   public float getBoost() {
     return boostAtt.getBoost();
   }
-
-  static CompiledAutomaton[] buildAutomata(String text, int[] termText, int prefixLength, boolean transpositions, int maxEdits) {
-    CompiledAutomaton[] compiled = new CompiledAutomaton[maxEdits + 1];
-    Automaton[] automata = buildAutomata(termText, prefixLength, transpositions, maxEdits);
-    for (int i = 0; i <= maxEdits; i++) {
-      try {
-        compiled[i] = new CompiledAutomaton(automata[i], true, false);
-      }
-      catch (TooComplexToDeterminizeException e) {
-        throw new FuzzyTermsException(text, e);
-      }
-    }
-    return compiled;
-  }
-
-  static int[] stringToUTF32(String text) {
-    int[] termText = new int[text.codePointCount(0, text.length())];
-    for (int cp, i = 0, j = 0; i < text.length(); i += Character.charCount(cp)) {
-      termText[j++] = cp = text.codePointAt(i);
-    }
-    return termText;
-  }
-
-  private static Automaton[] buildAutomata(int[] termText, int prefixLength, boolean transpositions, int maxEdits) {
-    if (maxEdits < 0 || maxEdits > LevenshteinAutomata.MAXIMUM_SUPPORTED_DISTANCE) {
-      throw new IllegalArgumentException("max edits must be 0.." + LevenshteinAutomata.MAXIMUM_SUPPORTED_DISTANCE + ", inclusive; got: " + maxEdits);
-    }
-    if (prefixLength < 0) {
-      throw new IllegalArgumentException("prefixLength cannot be less than 0");
-    }
-    Automaton[] automata = new Automaton[maxEdits + 1];
-    int termLength = termText.length;
-    prefixLength = Math.min(prefixLength, termLength);
-    String suffix = UnicodeUtil.newString(termText, prefixLength, termText.length - prefixLength);
-    LevenshteinAutomata builder = new LevenshteinAutomata(suffix, transpositions);
-    String prefix = UnicodeUtil.newString(termText, 0, prefixLength);
-    for (int i = 0; i <= maxEdits; i++) {
-      automata[i] = builder.toAutomaton(i, prefix);
-    }
-    return automata;
-  }
   
   /**
    * return an automata-based enum for matching up to editDistance from
@@ -274,7 +235,7 @@ public final class FuzzyTermsEnum extends TermsEnum {
       
     final float bottom = maxBoostAtt.getMaxNonCompetitiveBoost();
     final BytesRef bottomTerm = maxBoostAtt.getCompetitiveTerm();
-    if (term != null && (bottom != this.bottom || bottomTerm != this.bottomTerm)) {
+    if (bottom != this.bottom || bottomTerm != this.bottomTerm) {
       this.bottom = bottom;
       this.bottomTerm = bottomTerm;
       // clone the term before potentially doing something with it
@@ -364,4 +325,60 @@ public final class FuzzyTermsEnum extends TermsEnum {
     }
   }
 
+  /**
+   * Used for sharing automata between segments
+   *
+   * Levenshtein automata are large and expensive to build; we don't want to build
+   * them directly on the query because this can blow up caches that use queries
+   * as keys; we also don't want to rebuild them for every segment.  This attribute
+   * allows the FuzzyTermsEnum to build the automata once for its first segment
+   * and then share them for subsequent segment calls.
+   */
+  private interface AutomatonAttribute extends Attribute {
+    CompiledAutomaton[] getAutomata();
+    int getTermLength();
+    void init(Supplier<FuzzyAutomatonBuilder> builder);
+  }
+
+  private static class AutomatonAttributeImpl extends AttributeImpl implements AutomatonAttribute {
+
+    private CompiledAutomaton[] automata;
+    private int termLength;
+
+    @Override
+    public CompiledAutomaton[] getAutomata() {
+      return automata;
+    }
+
+    @Override
+    public int getTermLength() {
+      return termLength;
+    }
+
+    @Override
+    public void init(Supplier<FuzzyAutomatonBuilder> supplier) {
+      if (automata != null) {
+        return;
+      }
+      FuzzyAutomatonBuilder builder = supplier.get();
+      this.termLength = builder.getTermLength();
+      this.automata = builder.buildAutomatonSet();
+    }
+
+    @Override
+    public void clear() {
+      this.automata = null;
+    }
+
+    @Override
+    public void reflectWith(AttributeReflector reflector) {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void copyTo(AttributeImpl target) {
+      throw new UnsupportedOperationException();
+    }
+  }
+
 }

lucene/core/src/java/org/apache/lucene/search/MultiTermQuery.java

@@ -286,9 +286,9 @@ public abstract class MultiTermQuery extends Query {
    *  (should instead return {@link TermsEnum#EMPTY} if no
    *  terms match).  The TermsEnum must already be
    *  positioned to the first matching term.
-   * The given {@link AttributeSource} is passed by the {@link RewriteMethod} to
+   *  The given {@link AttributeSource} is passed by the {@link RewriteMethod} to
-   * provide attributes, the rewrite method uses to inform about e.g. maximum competitive boosts.
+   *  share information between segments, for example {@link TopTermsRewrite} uses
-   * This is currently only used by {@link TopTermsRewrite}
+   *  it to share maximum competitive boosts
    */
   protected abstract TermsEnum getTermsEnum(Terms terms, AttributeSource atts) throws IOException;
 

lucene/core/src/test/org/apache/lucene/search/TestFuzzyQuery.java

@@ -24,6 +24,8 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Supplier;
 
 import com.carrotsearch.randomizedtesting.RandomizedTest;
 import org.apache.lucene.analysis.MockAnalyzer;
@@ -36,15 +38,15 @@ import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.MultiReader;
 import org.apache.lucene.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.index.Terms;
-import org.apache.lucene.index.TermsEnum;
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.similarities.ClassicSimilarity;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.IOUtils;
 import org.apache.lucene.util.IntsRef;
 import org.apache.lucene.util.LuceneTestCase;
 import org.apache.lucene.util.TestUtil;
+import org.apache.lucene.util.automaton.ByteRunAutomaton;
 import org.apache.lucene.util.automaton.LevenshteinAutomata;
 import org.apache.lucene.util.automaton.Operations;
 
@@ -515,54 +517,13 @@ public class TestFuzzyQuery extends LuceneTestCase {
     final String value = randomRealisticMultiByteUnicode(length);
 
     FuzzyTermsEnum.FuzzyTermsException expected = expectThrows(FuzzyTermsEnum.FuzzyTermsException.class, () -> {
-      new FuzzyQuery(new Term("field", value)).getTermsEnum(new Terms() {
+      new FuzzyAutomatonBuilder(value, 2, 0, true).buildMaxEditAutomaton();
-        @Override
-        public TermsEnum iterator() {
-          return TermsEnum.EMPTY;
-        }
-
-        @Override
-        public long size() {
-          return 0;
-        }
-
-        @Override
-        public long getSumTotalTermFreq() {
-          throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public long getSumDocFreq() {
-          throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public int getDocCount() {
-          throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public boolean hasFreqs() {
-          throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public boolean hasOffsets() {
-          throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public boolean hasPositions() {
-          throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public boolean hasPayloads() {
-          throw new UnsupportedOperationException();
-        }
-      });
     });
     assertThat(expected.getMessage(), containsString(value));
+
+    expected = expectThrows(FuzzyTermsEnum.FuzzyTermsException.class,
+        () -> new FuzzyAutomatonBuilder(value, 2, 0, true).buildAutomatonSet());
+    assertThat(expected.getMessage(), containsString(value));
   }
 
   private void addDoc(String text, RandomIndexWriter writer) throws IOException {
@@ -777,4 +738,31 @@ public class TestFuzzyQuery extends LuceneTestCase {
     }
     return ref;
   }
+
+  public void testVisitor() {
+    FuzzyQuery q = new FuzzyQuery(new Term("field", "blob"), 2);
+    AtomicBoolean visited = new AtomicBoolean(false);
+    q.visit(new QueryVisitor() {
+      @Override
+      public void consumeTermsMatching(Query query, String field, Supplier<ByteRunAutomaton> automaton) {
+        visited.set(true);
+        ByteRunAutomaton a = automaton.get();
+        assertMatches(a, "blob");
+        assertMatches(a, "bolb");
+        assertMatches(a, "blobby");
+        assertNoMatches(a, "bolbby");
+      }
+    });
+    assertTrue(visited.get());
+  }
+
+  private static void assertMatches(ByteRunAutomaton automaton, String text) {
+    BytesRef b = new BytesRef(text);
+    assertTrue(automaton.run(b.bytes, b.offset, b.length));
+  }
+
+  private static void assertNoMatches(ByteRunAutomaton automaton, String text) {
+    BytesRef b = new BytesRef(text);
+    assertFalse(automaton.run(b.bytes, b.offset, b.length));
+  }
 }