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Customizing Snapshot creation

To customize the creation of snapshots, a Directive can be added to the Parser used in Polaroider.
Directives are added through the SnapshotOptions.

The simmplest directive has an inputstring and returns the altered string.

SnapshotOptions AddDirective(Func<string, string> directive)

// ignore all whitespaces by removing them
SnapshotOptions.Default.AddDirective(line => line.Replace(" ", string.Empty, StringComparison.OrdinalIgnoreCase));

It is possible to add multiple directives.
Directives are applied in the order that they are added.

// ignore all whitespaces by removing them
SnapshotOptions.Default.AddDirective(line => line.Replace(" ", string.Empty, StringComparison.OrdinalIgnoreCase));
// case insensitive comparison by converting all to uppercase
SnapshotOptions.Default.AddDirective(line => line.ToUpper());

Extensions

There are some Stringextensions that can be applied to the directive

Method Description
ReplaceRegex Replaces all parts of the string that apply to the regex
ReplaceGuid Replaces all Guids with the provided alternative. Defaults to 00000000-0000-0000-0000-000000000000

Examples

Add a directive to alter the value that is compared

var options = SnapshotOptions.Create(o =>
{
    // remove all whitespaces
    o.AddDirective(line => line.Replace(" ", string.Empty, StringComparison.OrdinalIgnoreCase));
    // alter all to uppercase
    o.AddDirective(line => line.ToUpper());
});

sn = new StringBuilder()
    .AppendLine("Line    1")
    .AppendLine("   Line 2")
    .AppendLine("  Line     3")
    .ToString();

sn.MatchSnapshot(options);