public async Task GetDescription_FileWithNonWhitespace_ReturnsSecondLineOfText_WhenFirstIsWhitespaceOnly()
{
var generator = new TextDescriptionGenerator();
var bytes = System.Text.Encoding.UTF8.GetBytes(" \r\nWorld");
var result = await generator.GetDescriptionAsync(bytes);
Assert.Equal("Text file beginning with 'World'", result);
}
public async Task GetDescription_FileWithWhitespaceOnly_ReturnsGenericDescription()
{
var generator = new TextDescriptionGenerator();
var bytes = System.Text.Encoding.UTF8.GetBytes(" \r\n ");
var result = await generator.GetDescriptionAsync(bytes);
Assert.Equal("Empty Text File", result);
}
public async Task GetDescription_FileWithNonWhitespace_ReturnsFirstLineOfText_UpToTwentyLetters()
{
var generator = new TextDescriptionGenerator();
var bytes = System.Text.Encoding.UTF8.GetBytes("ABCDEFGHIJKLMNOPQRSTUVWXYZ\nWorld");
var result = await generator.GetDescriptionAsync(bytes);
Assert.Equal("Text file beginning with 'ABCDEFGHIJKLMNOPQRST'", result);
}
public async Task GetDescription_HugeFileMadeOfWhitespace_ButWithTextAtEnd_ReturnsThatText()
{
var generator = new TextDescriptionGenerator();
var text = string.Concat(Enumerable.Repeat("\r\n", 4096)) + " Hello \r\nWorld";
var bytes = System.Text.Encoding.UTF8.GetBytes(text);
var result = await generator.GetDescriptionAsync(bytes);
Assert.Equal("Text file beginning with 'Hello'", result);
}
public async Task GetDescription_Throws_WhenContentIsNullOrEmpty()
{
var generator = new TextDescriptionGenerator();
var ex = await Assert.ThrowsAsync <ArgumentException>(
() => generator.GetDescriptionAsync(null).AsTask()
);
Assert.Contains("must contain data", ex.Message);
ex = await Assert.ThrowsAsync <ArgumentException>(
() => generator.GetDescriptionAsync(Array.Empty <byte>()).AsTask()
);
Assert.Contains("must contain data", ex.Message);
}
