public void WordFrequency_ThrowsArgumentNullException_WhenBookIsNull()
{
// Act
void action() => Question16_2.WordFrequency(null, "foo");
// Assert
TestHelpers.AssertExceptionThrown(action, typeof(ArgumentNullException));
}
public void WordFrequency_ThrowsArgumentNullException_WhenTargetWordIsNull()
{
// Arrange
var book = new[] { "foo" };
// Act
void action() => Question16_2.WordFrequency(book, null);
// Assert
TestHelpers.AssertExceptionThrown(action, typeof(ArgumentNullException));
}
public void WordFrequency_ReturnsFrequency_WithTwoWords()
{
// Arrange
var book = new[] { "foo", "bar" };
// Act
var result = Question16_2.WordFrequency(book, "foo");
// Assert
Assert.AreEqual(1, result);
}
public void WordFrequency_ReturnsZero_WithNoOccurrences()
{
// Arrange
var book = new[] { "foo" };
// Act
var result = Question16_2.WordFrequency(book, "bar");
// Assert
Assert.AreEqual(0, result);
}
public void WordFrequency_ReturnsFrequency_WithMultipleOccurrences()
{
// Arrange
var book = new[] { "foo", "foo" };
// Act
var result = Question16_2.WordFrequency(book, "foo");
// Assert
Assert.AreEqual(2, result);
}