public void Should_evaluate_formula_correctly()
{
// Arrange
SignedLiteral a = new SignedLiteral("A", false, true); // evaluates to true
SignedLiteral b = new SignedLiteral("B", false, false); // evaluates to false
SignedLiteral c = new SignedLiteral("C", true, true); // evaluates to false
Clause clause1 = new Clause(new List <SignedLiteral>()
{
a, b
}); // evaluates to true
Clause clause2 = new Clause(new List <SignedLiteral>()
{
a, c
}); // evaluates to true
Formula formula = new Formula(new List <Clause>()
{
clause1, clause2
});
// Act
bool formulaEvaluation = formula.Evaluate();
// Assert
Assert.IsTrue(formulaEvaluation);
// Re-arrange
a.Value = false; // both clauses now evaluate to false
// Act again
formulaEvaluation = formula.Evaluate();
//Assert
Assert.IsFalse(formulaEvaluation);
}
public void Should_evaluate_negative_literal_with_value_false_to_true()
{
SignedLiteral literal = new SignedLiteral("A", true);
literal.Value = false;
Assert.IsTrue(literal.Evaluate());
}
public void Should_evaluate_positive_literal_with_value_false_to_false()
{
SignedLiteral literal = new SignedLiteral("A", false);
literal.Value = false;
Assert.IsFalse(literal.Evaluate());
}
public void Should_display_clauses_with_single_literal_correctly()
{
// Arrange
SignedLiteral a = new SignedLiteral("A", false);
Clause clause = new Clause(new List <SignedLiteral>()
{
a
});
// Act
string clauseAsString = clause.ToString();
// Assert
Assert.AreEqual(clauseAsString, "(A)");
}
public void Should_swallow_duplicate_literals()
{
// Arrange
SignedLiteral a = new SignedLiteral("A", false);
SignedLiteral b = new SignedLiteral("B", true);
Clause clause = new Clause(new List <SignedLiteral>()
{
a, a, b, b
});
// Act
string clauseAsString = clause.ToString();
// Assert
Assert.AreEqual(clauseAsString, "(A ∨ ¬B)");
}
public void Should_display_clauses_with_or_signs()
{
// Arrange
SignedLiteral a = new SignedLiteral("A", false);
SignedLiteral b = new SignedLiteral("B", false);
Clause clause = new Clause(new List <SignedLiteral>()
{
a, b
});
// Act
string clauseAsString = clause.ToString();
// Assert
Assert.AreEqual(clauseAsString, "(A ∨ B)");
}
public void Should_evaluate_clause_with_mixed_valued_literals_to_true()
{
// Arrange
SignedLiteral a = new SignedLiteral("A", false, false);
SignedLiteral b = new SignedLiteral("B", false, true);
SignedLiteral c = new SignedLiteral("C", false, false);
Clause clause = new Clause(new List <SignedLiteral>()
{
a, b, c
});
// Act
bool clauseEvaluation = clause.Evaluate();
// Assert
Assert.IsTrue(clauseEvaluation);
}
// Returns the following formula: (A ∨ B) ∧ (A ∨ ¬C)
static internal Formula GetTestFormula()
{
SignedLiteral a = new SignedLiteral("A", false);
SignedLiteral b = new SignedLiteral("B", false);
SignedLiteral c = new SignedLiteral("C", true);
Clause clause1 = new Clause(new List <SignedLiteral>()
{
a, b
});
Clause clause2 = new Clause(new List <SignedLiteral>()
{
a, c
});
return(new Formula(new List <Clause>()
{
clause1, clause2
}));
}
public void Should_evaluate_clauses_with_negated_values_correctly()
{
// Arrange
SignedLiteral a = new SignedLiteral("A", true, false); // evaluates to true
SignedLiteral b = new SignedLiteral("B", false, false); // evaluates to false
SignedLiteral c = new SignedLiteral("C", false, true); // evaluates to true
SignedLiteral d = new SignedLiteral("D", true, true); // evaluates to false
Clause clause1 = new Clause(new List <SignedLiteral>()
{
a, b, c
});
Clause clause2 = new Clause(new List <SignedLiteral>()
{
a, c
});
Clause clause3 = new Clause(new List <SignedLiteral>()
{
a, b
});
Clause clause4 = new Clause(new List <SignedLiteral>()
{
b, d
});
// Act
bool clauseEvaluation1 = clause1.Evaluate();
bool clauseEvaluation2 = clause2.Evaluate();
bool clauseEvaluation3 = clause3.Evaluate();
bool clauseEvaluation4 = clause4.Evaluate();
// Assert
Assert.IsTrue(clauseEvaluation1);
Assert.IsTrue(clauseEvaluation2);
Assert.IsTrue(clauseEvaluation3);
Assert.IsFalse(clauseEvaluation4);
}
public void Should_display_positive_literal_without_not_sign()
{
SignedLiteral literal = new SignedLiteral("A", false);
Assert.AreEqual(literal.ToString(), "A");
}
public void Should_display_negative_literal_with_not_sign()
{
SignedLiteral literal = new SignedLiteral("A", true);
Assert.AreEqual(literal.ToString(), "¬A");
}
