code: ///////////////////////////////////////////////////////////////////////////
  //                   __                _      _   ________               //
  //                  / /   ____  ____ _(_)____/ | / / ____/               //
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  //                           /____/                                      //
  //                                                                       //
  //               The Next Generation Logic Library                       //
  //                                                                       //
  ///////////////////////////////////////////////////////////////////////////
  //                                                                       //
  //  Copyright 2015-20xx Christoph Zengler                                //
  //                                                                       //
  //  Licensed 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.                       //
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  ///////////////////////////////////////////////////////////////////////////
  
  package org.logicng.transformations;
  
  import static org.assertj.core.api.Assertions.assertThat;
  
  import org.junit.jupiter.api.Test;
  import org.logicng.datastructures.Substitution;
  import org.logicng.formulas.Formula;
  import org.logicng.formulas.FormulaFactory;
  import org.logicng.formulas.Variable;
  import org.logicng.io.parsers.ParserException;
  import org.logicng.io.parsers.PseudoBooleanParser;
  
  import java.util.HashMap;
  
  /**
   * Unit tests for {@link Anonymizer}.
   * @version 2.0.0
   * @since 1.4.0
   */
  public class AnonymizerTest {
  
      @Test
      public void testSimpleFormulasDefault() throws ParserException {
          final FormulaFactory f = new FormulaFactory();
          final PseudoBooleanParser p = new PseudoBooleanParser(f);
          final Anonymizer anonymizer = new Anonymizer();
          assertThat(p.parse("$true").transform(anonymizer)).isEqualTo(p.parse("$true"));
          assertThat(p.parse("$false").transform(anonymizer)).isEqualTo(p.parse("$false"));
          assertThat(p.parse("A").transform(anonymizer)).isEqualTo(p.parse("v0"));
          assertThat(p.parse("~A").transform(anonymizer)).isEqualTo(p.parse("~v0"));
          assertThat(p.parse("A => ~B").transform(anonymizer)).isEqualTo(p.parse("v0 => ~v1"));
          assertThat(p.parse("A <=> ~B").transform(anonymizer)).isEqualTo(p.parse("v0 <=> ~v1"));
          assertThat(p.parse("A | B | ~D | C").transform(anonymizer)).isEqualTo(p.parse("v0 | v1 | ~v3 | v2"));
          assertThat(p.parse("A & B & C & ~D").transform(anonymizer)).isEqualTo(p.parse("v0 & v1 & v2 & ~v3"));
      }
  
      @Test
      public void testSimpleFormulasOwnPrefix() throws ParserException {
          final FormulaFactory f = new FormulaFactory();
          final PseudoBooleanParser p = new PseudoBooleanParser(f);
          final Anonymizer anonymizer = new Anonymizer("var");
          assertThat(p.parse("$true").transform(anonymizer)).isEqualTo(p.parse("$true"));
          assertThat(p.parse("$false").transform(anonymizer)).isEqualTo(p.parse("$false"));
          assertThat(p.parse("A").transform(anonymizer)).isEqualTo(p.parse("var0"));
          assertThat(p.parse("~A").transform(anonymizer)).isEqualTo(p.parse("~var0"));
          assertThat(p.parse("A => ~B").transform(anonymizer)).isEqualTo(p.parse("var0 => ~var1"));
          assertThat(p.parse("A <=> ~B").transform(anonymizer)).isEqualTo(p.parse("var0 <=> ~var1"));
          assertThat(p.parse("A <=> ~B").transform(anonymizer)).isEqualTo(p.parse("var0 <=> ~var1"));
          assertThat(p.parse("A | B | ~D | C").transform(anonymizer)).isEqualTo(p.parse("var0 | var1 | ~var3 | var2"));
          assertThat(p.parse("A & B & C & ~D").transform(anonymizer)).isEqualTo(p.parse("var0 & var1 & var2 & ~var3"));
      }
  
      @Test
      public void testSimpleFormulasOwnPrefixAndCounter() throws ParserException {
          final FormulaFactory f = new FormulaFactory();
          final PseudoBooleanParser p = new PseudoBooleanParser(f);
          final Anonymizer anonymizer = new Anonymizer("var", 10);
          assertThat(p.parse("$true").transform(anonymizer)).isEqualTo(p.parse("$true"));
          assertThat(p.parse("$false").transform(anonymizer)).isEqualTo(p.parse("$false"));
          assertThat(p.parse("A").transform(anonymizer)).isEqualTo(p.parse("var10"));
          assertThat(p.parse("~A").transform(anonymizer)).isEqualTo(p.parse("~var10"));
          assertThat(p.parse("A => ~B").transform(anonymizer)).isEqualTo(p.parse("var10 => ~var11"));
          assertThat(p.parse("A <=> ~B").transform(anonymizer)).isEqualTo(p.parse("var10 <=> ~var11"));
          assertThat(p.parse("A | B | ~D | C").transform(anonymizer)).isEqualTo(p.parse("var10 | var11 | ~var13 | var12"));
          assertThat(p.parse("A & B & C & ~D").transform(anonymizer)).isEqualTo(p.parse("var10 & var11 & var12 & ~var13"));
      }
  
      @Test
      public void testSimpleFormulasOwnPrefixAndCounterWithoutCache() throws ParserException {
          final FormulaFactory f = new FormulaFactory();
          final PseudoBooleanParser p = new PseudoBooleanParser(f);
          final Anonymizer anonymizer = new Anonymizer("var", 10);
          assertThat(p.parse("$true").transform(anonymizer, false)).isEqualTo(p.parse("$true"));
          assertThat(p.parse("$false").transform(anonymizer, false)).isEqualTo(p.parse("$false"));
          assertThat(p.parse("A").transform(anonymizer, false)).isEqualTo(p.parse("var10"));
          assertThat(p.parse("~A").transform(anonymizer, false)).isEqualTo(p.parse("~var10"));
          assertThat(p.parse("A => ~B").transform(anonymizer, false)).isEqualTo(p.parse("var10 => ~var11"));
          assertThat(p.parse("A <=> ~B").transform(anonymizer, false)).isEqualTo(p.parse("var10 <=> ~var11"));
          assertThat(p.parse("A | B | ~D | C").transform(anonymizer, false)).isEqualTo(p.parse("var10 | var11 | ~var13 | var12"));
          assertThat(p.parse("A & B & C & ~D").transform(anonymizer, false)).isEqualTo(p.parse("var10 & var11 & var12 & ~var13"));
      }
  
      @Test
      public void testGetSubstitution() throws ParserException {
          final FormulaFactory f = new FormulaFactory();
          final PseudoBooleanParser p = new PseudoBooleanParser(f);
          final Anonymizer anonymizer = new Anonymizer("v", 0);
          assertThat(anonymizer.getSubstitution()).isEqualTo(new Substitution());
          assertThat(p.parse("A & B & C & ~D").transform(anonymizer, false)).isEqualTo(p.parse("v0 & v1 & v2 & ~v3"));
          final HashMap<Variable, Formula> mapping = new HashMap<>();
          mapping.put(f.variable("A"), f.variable("v0"));
          mapping.put(f.variable("B"), f.variable("v1"));
          mapping.put(f.variable("C"), f.variable("v2"));
          mapping.put(f.variable("D"), f.variable("v3"));
          assertThat(anonymizer.getSubstitution()).isEqualTo(new Substitution(mapping));
          assertThat(p.parse("E & A & C & ~F").transform(anonymizer, false)).isEqualTo(p.parse("v4 & v0 & v2 & ~v5"));
          mapping.put(f.variable("E"), f.variable("v4"));
          mapping.put(f.variable("F"), f.variable("v5"));
          assertThat(anonymizer.getSubstitution()).isEqualTo(new Substitution(mapping));
      }
  }
  