public static void verifyEquals(Fields d1, Fields d2) throws IOException {
    if (d1 == null) {
      assertTrue(d2 == null || d2.size() == 0);
      return;
    }
    assertTrue(d2 != null);

    Iterator<String> fieldsEnum2 = d2.iterator();

    for (String field1 : d1) {
      String field2 = fieldsEnum2.next();
      assertEquals(field1, field2);

      Terms terms1 = d1.terms(field1);
      assertNotNull(terms1);
      TermsEnum termsEnum1 = terms1.iterator(null);

      Terms terms2 = d2.terms(field2);
      assertNotNull(terms2);
      TermsEnum termsEnum2 = terms2.iterator(null);

      DocsAndPositionsEnum dpEnum1 = null;
      DocsAndPositionsEnum dpEnum2 = null;
      DocsEnum dEnum1 = null;
      DocsEnum dEnum2 = null;

      BytesRef term1;
      while ((term1 = termsEnum1.next()) != null) {
        BytesRef term2 = termsEnum2.next();
        assertEquals(term1, term2);
        assertEquals(termsEnum1.totalTermFreq(), termsEnum2.totalTermFreq());

        dpEnum1 = termsEnum1.docsAndPositions(null, dpEnum1);
        dpEnum2 = termsEnum2.docsAndPositions(null, dpEnum2);
        if (dpEnum1 != null) {
          assertNotNull(dpEnum2);
          int docID1 = dpEnum1.nextDoc();
          dpEnum2.nextDoc();
          // docIDs are not supposed to be equal
          // int docID2 = dpEnum2.nextDoc();
          // assertEquals(docID1, docID2);
          assertTrue(docID1 != DocIdSetIterator.NO_MORE_DOCS);

          int freq1 = dpEnum1.freq();
          int freq2 = dpEnum2.freq();
          assertEquals(freq1, freq2);
          OffsetAttribute offsetAtt1 =
              dpEnum1.attributes().hasAttribute(OffsetAttribute.class)
                  ? dpEnum1.attributes().getAttribute(OffsetAttribute.class)
                  : null;
          OffsetAttribute offsetAtt2 =
              dpEnum2.attributes().hasAttribute(OffsetAttribute.class)
                  ? dpEnum2.attributes().getAttribute(OffsetAttribute.class)
                  : null;

          if (offsetAtt1 != null) {
            assertNotNull(offsetAtt2);
          } else {
            assertNull(offsetAtt2);
          }

          for (int posUpto = 0; posUpto < freq1; posUpto++) {
            int pos1 = dpEnum1.nextPosition();
            int pos2 = dpEnum2.nextPosition();
            assertEquals(pos1, pos2);
            if (offsetAtt1 != null) {
              assertEquals(offsetAtt1.startOffset(), offsetAtt2.startOffset());
              assertEquals(offsetAtt1.endOffset(), offsetAtt2.endOffset());
            }
          }
          assertEquals(DocIdSetIterator.NO_MORE_DOCS, dpEnum1.nextDoc());
          assertEquals(DocIdSetIterator.NO_MORE_DOCS, dpEnum2.nextDoc());
        } else {
          dEnum1 = TestUtil.docs(random(), termsEnum1, null, dEnum1, DocsEnum.FLAG_FREQS);
          dEnum2 = TestUtil.docs(random(), termsEnum2, null, dEnum2, DocsEnum.FLAG_FREQS);
          assertNotNull(dEnum1);
          assertNotNull(dEnum2);
          int docID1 = dEnum1.nextDoc();
          dEnum2.nextDoc();
          // docIDs are not supposed to be equal
          // int docID2 = dEnum2.nextDoc();
          // assertEquals(docID1, docID2);
          assertTrue(docID1 != DocIdSetIterator.NO_MORE_DOCS);
          int freq1 = dEnum1.freq();
          int freq2 = dEnum2.freq();
          assertEquals(freq1, freq2);
          assertEquals(DocIdSetIterator.NO_MORE_DOCS, dEnum1.nextDoc());
          assertEquals(DocIdSetIterator.NO_MORE_DOCS, dEnum2.nextDoc());
        }
      }

      assertNull(termsEnum2.next());
    }
    assertFalse(fieldsEnum2.hasNext());
  }
  public void verifyEquals(DirectoryReader r1, DirectoryReader r2, String idField)
      throws Throwable {
    if (VERBOSE) {
      System.out.println("\nr1 docs:");
      printDocs(r1);
      System.out.println("\nr2 docs:");
      printDocs(r2);
    }
    if (r1.numDocs() != r2.numDocs()) {
      assert false : "r1.numDocs()=" + r1.numDocs() + " vs r2.numDocs()=" + r2.numDocs();
    }
    boolean hasDeletes = !(r1.maxDoc() == r2.maxDoc() && r1.numDocs() == r1.maxDoc());

    int[] r2r1 = new int[r2.maxDoc()]; // r2 id to r1 id mapping

    // create mapping from id2 space to id2 based on idField
    final Fields f1 = MultiFields.getFields(r1);
    if (f1 == null) {
      // make sure r2 is empty
      assertNull(MultiFields.getFields(r2));
      return;
    }
    final Terms terms1 = f1.terms(idField);
    if (terms1 == null) {
      assertTrue(
          MultiFields.getFields(r2) == null || MultiFields.getFields(r2).terms(idField) == null);
      return;
    }
    final TermsEnum termsEnum = terms1.iterator(null);

    final Bits liveDocs1 = MultiFields.getLiveDocs(r1);
    final Bits liveDocs2 = MultiFields.getLiveDocs(r2);

    Fields fields = MultiFields.getFields(r2);
    if (fields == null) {
      // make sure r1 is in fact empty (eg has only all
      // deleted docs):
      Bits liveDocs = MultiFields.getLiveDocs(r1);
      DocsEnum docs = null;
      while (termsEnum.next() != null) {
        docs = TestUtil.docs(random(), termsEnum, liveDocs, docs, DocsEnum.FLAG_NONE);
        while (docs.nextDoc() != DocIdSetIterator.NO_MORE_DOCS) {
          fail("r1 is not empty but r2 is");
        }
      }
      return;
    }
    Terms terms2 = fields.terms(idField);
    TermsEnum termsEnum2 = terms2.iterator(null);

    DocsEnum termDocs1 = null;
    DocsEnum termDocs2 = null;

    while (true) {
      BytesRef term = termsEnum.next();
      // System.out.println("TEST: match id term=" + term);
      if (term == null) {
        break;
      }

      termDocs1 = TestUtil.docs(random(), termsEnum, liveDocs1, termDocs1, DocsEnum.FLAG_NONE);
      if (termsEnum2.seekExact(term)) {
        termDocs2 = TestUtil.docs(random(), termsEnum2, liveDocs2, termDocs2, DocsEnum.FLAG_NONE);
      } else {
        termDocs2 = null;
      }

      if (termDocs1.nextDoc() == DocIdSetIterator.NO_MORE_DOCS) {
        // This doc is deleted and wasn't replaced
        assertTrue(termDocs2 == null || termDocs2.nextDoc() == DocIdSetIterator.NO_MORE_DOCS);
        continue;
      }

      int id1 = termDocs1.docID();
      assertEquals(DocIdSetIterator.NO_MORE_DOCS, termDocs1.nextDoc());

      assertTrue(termDocs2.nextDoc() != DocIdSetIterator.NO_MORE_DOCS);
      int id2 = termDocs2.docID();
      assertEquals(DocIdSetIterator.NO_MORE_DOCS, termDocs2.nextDoc());

      r2r1[id2] = id1;

      // verify stored fields are equivalent
      try {
        verifyEquals(r1.document(id1), r2.document(id2));
      } catch (Throwable t) {
        System.out.println("FAILED id=" + term + " id1=" + id1 + " id2=" + id2 + " term=" + term);
        System.out.println("  d1=" + r1.document(id1));
        System.out.println("  d2=" + r2.document(id2));
        throw t;
      }

      try {
        // verify term vectors are equivalent
        verifyEquals(r1.getTermVectors(id1), r2.getTermVectors(id2));
      } catch (Throwable e) {
        System.out.println("FAILED id=" + term + " id1=" + id1 + " id2=" + id2);
        Fields tv1 = r1.getTermVectors(id1);
        System.out.println("  d1=" + tv1);
        if (tv1 != null) {
          DocsAndPositionsEnum dpEnum = null;
          DocsEnum dEnum = null;
          for (String field : tv1) {
            System.out.println("    " + field + ":");
            Terms terms3 = tv1.terms(field);
            assertNotNull(terms3);
            TermsEnum termsEnum3 = terms3.iterator(null);
            BytesRef term2;
            while ((term2 = termsEnum3.next()) != null) {
              System.out.println(
                  "      " + term2.utf8ToString() + ": freq=" + termsEnum3.totalTermFreq());
              dpEnum = termsEnum3.docsAndPositions(null, dpEnum);
              if (dpEnum != null) {
                assertTrue(dpEnum.nextDoc() != DocIdSetIterator.NO_MORE_DOCS);
                final int freq = dpEnum.freq();
                System.out.println("        doc=" + dpEnum.docID() + " freq=" + freq);
                for (int posUpto = 0; posUpto < freq; posUpto++) {
                  System.out.println("          pos=" + dpEnum.nextPosition());
                }
              } else {
                dEnum = TestUtil.docs(random(), termsEnum3, null, dEnum, DocsEnum.FLAG_FREQS);
                assertNotNull(dEnum);
                assertTrue(dEnum.nextDoc() != DocIdSetIterator.NO_MORE_DOCS);
                final int freq = dEnum.freq();
                System.out.println("        doc=" + dEnum.docID() + " freq=" + freq);
              }
            }
          }
        }

        Fields tv2 = r2.getTermVectors(id2);
        System.out.println("  d2=" + tv2);
        if (tv2 != null) {
          DocsAndPositionsEnum dpEnum = null;
          DocsEnum dEnum = null;
          for (String field : tv2) {
            System.out.println("    " + field + ":");
            Terms terms3 = tv2.terms(field);
            assertNotNull(terms3);
            TermsEnum termsEnum3 = terms3.iterator(null);
            BytesRef term2;
            while ((term2 = termsEnum3.next()) != null) {
              System.out.println(
                  "      " + term2.utf8ToString() + ": freq=" + termsEnum3.totalTermFreq());
              dpEnum = termsEnum3.docsAndPositions(null, dpEnum);
              if (dpEnum != null) {
                assertTrue(dpEnum.nextDoc() != DocIdSetIterator.NO_MORE_DOCS);
                final int freq = dpEnum.freq();
                System.out.println("        doc=" + dpEnum.docID() + " freq=" + freq);
                for (int posUpto = 0; posUpto < freq; posUpto++) {
                  System.out.println("          pos=" + dpEnum.nextPosition());
                }
              } else {
                dEnum = TestUtil.docs(random(), termsEnum3, null, dEnum, DocsEnum.FLAG_FREQS);
                assertNotNull(dEnum);
                assertTrue(dEnum.nextDoc() != DocIdSetIterator.NO_MORE_DOCS);
                final int freq = dEnum.freq();
                System.out.println("        doc=" + dEnum.docID() + " freq=" + freq);
              }
            }
          }
        }

        throw e;
      }
    }

    // System.out.println("TEST: done match id");

    // Verify postings
    // System.out.println("TEST: create te1");
    final Fields fields1 = MultiFields.getFields(r1);
    final Iterator<String> fields1Enum = fields1.iterator();
    final Fields fields2 = MultiFields.getFields(r2);
    final Iterator<String> fields2Enum = fields2.iterator();

    String field1 = null, field2 = null;
    TermsEnum termsEnum1 = null;
    termsEnum2 = null;
    DocsEnum docs1 = null, docs2 = null;

    // pack both doc and freq into single element for easy sorting
    long[] info1 = new long[r1.numDocs()];
    long[] info2 = new long[r2.numDocs()];

    for (; ; ) {
      BytesRef term1 = null, term2 = null;

      // iterate until we get some docs
      int len1;
      for (; ; ) {
        len1 = 0;
        if (termsEnum1 == null) {
          if (!fields1Enum.hasNext()) {
            break;
          }
          field1 = fields1Enum.next();
          Terms terms = fields1.terms(field1);
          if (terms == null) {
            continue;
          }
          termsEnum1 = terms.iterator(null);
        }
        term1 = termsEnum1.next();
        if (term1 == null) {
          // no more terms in this field
          termsEnum1 = null;
          continue;
        }

        // System.out.println("TEST: term1=" + term1);
        docs1 = TestUtil.docs(random(), termsEnum1, liveDocs1, docs1, DocsEnum.FLAG_FREQS);
        while (docs1.nextDoc() != DocIdSetIterator.NO_MORE_DOCS) {
          int d = docs1.docID();
          int f = docs1.freq();
          info1[len1] = (((long) d) << 32) | f;
          len1++;
        }
        if (len1 > 0) break;
      }

      // iterate until we get some docs
      int len2;
      for (; ; ) {
        len2 = 0;
        if (termsEnum2 == null) {
          if (!fields2Enum.hasNext()) {
            break;
          }
          field2 = fields2Enum.next();
          Terms terms = fields2.terms(field2);
          if (terms == null) {
            continue;
          }
          termsEnum2 = terms.iterator(null);
        }
        term2 = termsEnum2.next();
        if (term2 == null) {
          // no more terms in this field
          termsEnum2 = null;
          continue;
        }

        // System.out.println("TEST: term1=" + term1);
        docs2 = TestUtil.docs(random(), termsEnum2, liveDocs2, docs2, DocsEnum.FLAG_FREQS);
        while (docs2.nextDoc() != DocIdSetIterator.NO_MORE_DOCS) {
          int d = r2r1[docs2.docID()];
          int f = docs2.freq();
          info2[len2] = (((long) d) << 32) | f;
          len2++;
        }
        if (len2 > 0) break;
      }

      assertEquals(len1, len2);
      if (len1 == 0) break; // no more terms

      assertEquals(field1, field2);
      assertTrue(term1.bytesEquals(term2));

      if (!hasDeletes) assertEquals(termsEnum1.docFreq(), termsEnum2.docFreq());

      assertEquals("len1=" + len1 + " len2=" + len2 + " deletes?=" + hasDeletes, term1, term2);

      // sort info2 to get it into ascending docid
      Arrays.sort(info2, 0, len2);

      // now compare
      for (int i = 0; i < len1; i++) {
        assertEquals(
            "i="
                + i
                + " len="
                + len1
                + " d1="
                + (info1[i] >>> 32)
                + " f1="
                + (info1[i] & Integer.MAX_VALUE)
                + " d2="
                + (info2[i] >>> 32)
                + " f2="
                + (info2[i] & Integer.MAX_VALUE)
                + " field="
                + field1
                + " term="
                + term1.utf8ToString(),
            info1[i],
            info2[i]);
      }
    }
  }