001 /*
002 * Created on Dec 4, 2004
003 *
004 */
005 package aima.test.logictest.prop.visitors;
006
007 import junit.framework.TestCase;
008 import aima.logic.propositional.parsing.PEParser;
009 import aima.logic.propositional.parsing.ast.Sentence;
010 import aima.logic.propositional.visitors.CNFTransformer;
011
012 /**
013 * @author Ravi Mohan
014 *
015 */
016 public class CNFTransformerTest extends TestCase {
017 private PEParser parser = new PEParser();
018
019 private CNFTransformer transformer;
020
021 @Override
022 public void setUp() {
023 transformer = new CNFTransformer();
024 }
025
026 public void testSymbolTransform() {
027 Sentence symbol = (Sentence) parser.parse("A");
028 Sentence transformed = transformer.transform(symbol);
029 assertEquals("A", transformed.toString());
030 }
031
032 public void testBasicSentenceTransformation() {
033 Sentence and = (Sentence) parser.parse("(A AND B)");
034 Sentence transformedAnd = transformer.transform(and);
035 assertEquals(and.toString(), transformedAnd.toString());
036
037 Sentence or = (Sentence) parser.parse("(A OR B)");
038 Sentence transformedOr = transformer.transform(or);
039 assertEquals(or.toString(), transformedOr.toString());
040
041 Sentence not = (Sentence) parser.parse("(NOT C)");
042 Sentence transformedNot = transformer.transform(not);
043 assertEquals(not.toString(), transformedNot.toString());
044 }
045
046 public void testImplicationTransformation() {
047 Sentence impl = (Sentence) parser.parse("(A => B)");
048 Sentence expected = (Sentence) parser.parse("((NOT A) OR B)");
049 Sentence transformedImpl = transformer.transform(impl);
050 assertEquals(expected.toString(), transformedImpl.toString());
051 }
052
053 public void testBiConditionalTransformation() {
054 Sentence bic = (Sentence) parser.parse("(A <=> B)");
055 Sentence expected = (Sentence) parser
056 .parse("(((NOT A) OR B) AND ((NOT B) OR A)) ");
057 Sentence transformedBic = transformer.transform(bic);
058 assertEquals(expected.toString(), transformedBic.toString());
059 }
060
061 public void testTwoSuccessiveNotsTransformation() {
062 Sentence twoNots = (Sentence) parser.parse("(NOT (NOT A))");
063 Sentence expected = (Sentence) parser.parse("A");
064 Sentence transformed = transformer.transform(twoNots);
065 assertEquals(expected.toString(), transformed.toString());
066 }
067
068 public void testThreeSuccessiveNotsTransformation() {
069 Sentence threeNots = (Sentence) parser.parse("(NOT (NOT (NOT A)))");
070 Sentence expected = (Sentence) parser.parse("(NOT A)");
071 Sentence transformed = transformer.transform(threeNots);
072 assertEquals(expected.toString(), transformed.toString());
073 }
074
075 public void testFourSuccessiveNotsTransformation() {
076 Sentence fourNots = (Sentence) parser
077 .parse("(NOT (NOT (NOT (NOT A))))");
078 Sentence expected = (Sentence) parser.parse("A");
079 Sentence transformed = transformer.transform(fourNots);
080 assertEquals(expected.toString(), transformed.toString());
081 }
082
083 public void testDeMorgan1() {
084 Sentence dm = (Sentence) parser.parse("(NOT (A AND B))");
085 Sentence expected = (Sentence) parser.parse("((NOT A) OR (NOT B))");
086 Sentence transformed = transformer.transform(dm);
087 assertEquals(expected.toString(), transformed.toString());
088 }
089
090 public void testDeMorgan2() {
091 Sentence dm = (Sentence) parser.parse("(NOT (A OR B))");
092 Sentence expected = (Sentence) parser.parse("((NOT A) AND (NOT B))");
093 Sentence transformed = transformer.transform(dm);
094 assertEquals(expected.toString(), transformed.toString());
095 }
096
097 public void testOrDistribution1() {
098 Sentence or = (Sentence) parser.parse("((A AND B) OR C)");
099 Sentence expected = (Sentence) parser.parse("((C OR A) AND (C OR B))");
100 Sentence transformed = transformer.transform(or);
101 assertEquals(expected.toString(), transformed.toString());
102 }
103
104 public void testOrDistribution2() {
105 Sentence or = (Sentence) parser.parse("(A OR (B AND C))");
106 Sentence expected = (Sentence) parser.parse("((A OR B) AND (A OR C))");
107 Sentence transformed = transformer.transform(or);
108 assertEquals(expected.toString(), transformed.toString());
109 }
110
111 public void testAimaExample() {
112 Sentence aimaEg = (Sentence) parser.parse("( B11 <=> (P12 OR P21))");
113 Sentence expected = (Sentence) parser
114 .parse(" ( ( ( NOT B11 ) OR ( P12 OR P21 ) ) AND ( ( B11 OR ( NOT P12 ) ) AND ( B11 OR ( NOT P21 ) ) ) )");
115 Sentence transformed = transformer.transform(aimaEg);
116 assertEquals(expected.toString(), transformed.toString());
117 }
118
119 }