public void Simplify_NonSimplifiablTruthTable_ShouldResultInTheOriginalTruthTable(string toParseExpression)
{
// Same number of rows
// These should result in the same sets of rows
parser = new Parser(toParseExpression);
Proposition root = parser.Parse();
TruthTable tt = new TruthTable(root);
// Act
TruthTable simplifiedTt = tt.Simplify();
// Assert
tt.Rows.Count.Should().Be(simplifiedTt.Rows.Count, "Because the expression could not be simplified");
}
public void Simplify_SimplifiableTruthTable_ShouldResultInSimplifiedTruthTable(string toParseExpression)
{
// A simplified truth table has less rows than the original.
// They are also flagged as simplified and for that reason treated differently
// Arrange
parser = new Parser(toParseExpression);
Proposition root = parser.Parse();
TruthTable tt = new TruthTable(root);
// Act
TruthTable simplifiedTt = tt.Simplify();
// Assert
tt.Rows.Count.Should().BeGreaterThan(simplifiedTt.Rows.Count, "Because the simplified truth table should have less rows as some could be simplified");
}
public void CreateDisjunctiveNormalForm_NegatedProposition_ExpectedOriginalNegatedPropositionReturned()
{
// Arrange
Proposition originalProposition = PropositionGenerator.CreateUnaryConnectiveWithRandomSymbol(Negation.SYMBOL);
TruthTable tt = new TruthTable(originalProposition);
TruthTable simplifiedTt = tt.Simplify();
// Act
Proposition dnf = tt.CreateDisjunctiveNormalForm();
Proposition simplifiedDnf = simplifiedTt.CreateDisjunctiveNormalForm();
// Assert
dnf.Should().BeEquivalentTo(originalProposition, "Because the disjunctive normal of a negated proposition literal is the negated literal itself");
simplifiedDnf.Should().BeEquivalentTo(originalProposition, "Because a negated literal can not be simplified any further and should result in the negated literal itself.");
}
public void CreateDisjunctiveNormalForm_IndividualPropositionGiven_ExpectedIndividualPropositionReturned()
{
// Arrange
Proposition originalProposition = PropositionGenerator.GetRandomProposition();
TruthTable tt = new TruthTable(originalProposition);
TruthTable simplifiedTt = tt.Simplify();
// Act
Proposition dnf = tt.CreateDisjunctiveNormalForm();
Proposition simplifiedDnf = simplifiedTt.CreateDisjunctiveNormalForm();
// Assert
dnf.Should().BeEquivalentTo(originalProposition, "Because the disjunctive normal of a proposition literal is the literal itself");
simplifiedDnf.Should().BeEquivalentTo(originalProposition, "Because a literal can not be simplified any further and should result in the literal itself.");
}
public void CreateDisjunctiveNormalForm_ExpressionGiven_ExpectedPropositionLiteralsAtTheLeavesAndNoDisjunctionDeeperThanConjunction(char expressionSymbol)
{
// For the binary connectives, we should check all (both) possible branches if they contain
// no disjunction below a conjunction
// Arrange
BinaryConnective root = PropositionGenerator.CreateBinaryConnectiveWithRandomSymbols(expressionSymbol);
TruthTable tt = new TruthTable(root);
TruthTable simplifiedTt = tt.Simplify();
// Act
Proposition dnf = tt.CreateDisjunctiveNormalForm();
Proposition simplifiedDnf = simplifiedTt.CreateDisjunctiveNormalForm();
// Assert
Assert.True(IsInDnf(dnf), "Because this expression should be in DNF");
Assert.True(IsInDnf(simplifiedDnf), "Because the simplified expression should also be in DNF");
}
public void GetSimplifiedExpression_ExpressionWithoutDoNotCareVariableGiven_ExpectedEqualNumberOfVariablesInProposition(string nonSimplifiableExpression)
{
// Arrange
parser = new Parser(nonSimplifiableExpression);
Proposition nonSimplifiableProposition = parser.Parse();
TruthTable truthTable = new TruthTable(nonSimplifiableProposition);
TruthTable simplifiedTruthTable = truthTable.Simplify();
Proposition afterSimplifying = simplifiedTruthTable.GetSimplifiedExpression();
// Act
int numberOfVariablesInOriginal = nonSimplifiableProposition.GetVariables().Count;
int actualNumberOfVariablesInSimplified = afterSimplifying.GetVariables().Count;
int actualNumberOfDontCareVariables = numberOfVariablesInOriginal - actualNumberOfVariablesInSimplified;
// Assert
actualNumberOfDontCareVariables.Should().Be(0, $"Because the proposition could NOT be simplified thus should have a difference of 0");
}
public void GetSimplifiedExpression_ExpressionWithDoNotCareVariableGiven_ExpectedDoNoCareVariableToBeRemovedFromProposition(string simplifiableExpression, int numberOfDoNotCareVariables)
{
// Arrange
parser = new Parser(simplifiableExpression);
Proposition simplifiableProposition = parser.Parse();
TruthTable truthTable = new TruthTable(simplifiableProposition);
TruthTable simplifiedTruthTable = truthTable.Simplify();
Proposition afterSimplifying = simplifiedTruthTable.GetSimplifiedExpression();
// Act
int numberOfVariablesInOriginal = simplifiableProposition.GetVariables().Count;
int actualNumberOfVariablesInSimplified = afterSimplifying.GetVariables().Count;
int actualNumberOfDontCareVariables = numberOfVariablesInOriginal - actualNumberOfVariablesInSimplified;
// Assert
actualNumberOfDontCareVariables.Should().Be(numberOfDoNotCareVariables, $"Because the proposition could be simplified and {numberOfDoNotCareVariables} variables should be removed from the original expression that has {numberOfVariablesInOriginal} variables");
}
public void Simplify_Should_Produce_Valid_Simplified_TruthTableValues()
{
TruthTable table = new TruthTable(VALID_TRUTHTABLE_VALUES);
table.Simplify().Should().BeEquivalentTo(VALID_SIMPLIFIED_TRUTHTABLE_VALUES);
}
