Recording

Recording allows information to be statically captured and then (optionally) verified.

The main value of this feature is to simplify addition of information to a snapshot from extensions to Verify. Before to this feature, for an extension to supply information to a snapshot, that extension had to return the information up the stack, and the calling test had to explicitly add that information to the Verify() call. Using this feature an extension can Recording.Add() in any context, and the information will be added to the snapshot.

Usage

[Fact]
public Task Usage()
{
    Recording.Start();
    Recording.Add("name", "value");
    return Verify("TheValue");
}

^{snippet source | anchor}

Results in:

{
  target: TheValue,
  name: value
}

^{snippet source | anchor}

TryAdd

If Recording.Add() is called before Recording.Start an exception will be called.

Recording.TryAdd() will add an item only if Recording.IsRecording is true.

[Fact]
public Task TryAdd()
{
    //using Recording.Add here would throw since Recording.Start has not been called
    Recording.TryAdd("name1", "value1");
    Recording.Start();
    Recording.TryAdd("name2", "value2");
    return Verify("TheValue");
}

^{snippet source | anchor}

Scoped

Recording can be scoped via a using:

[Fact]
public Task RecordingScoped()
{
    using (Recording.Start())
    {
        Recording.Add("name1", "value1");
    }

    // Recording.Add is ignored here
    Recording.Add("name2", "value2");
    return Verify();
}

^{snippet source | anchor}

Results in:

{
  name1: value1
}

^{snippet source | anchor}

Grouping

Values are grouped by key:

[Fact]
public Task SameKey()
{
    Recording.Start();
    Recording.Add("name", "value1");
    Recording.Add("name", "value2");
    return Verify("TheValue");
}

^{snippet source | anchor}

Results in:

{
  target: TheValue,
  name: [
    value1,
    value2
  ]
}

^{snippet source | anchor}

To avoid grouping use Stop.

Identifier

Recording can be grouped by an identifier.

The identifier should be statically unique. For example a fully qualified test name or a GUID.

[Fact]
public Task Identifier()
{
    Recording.Start("identifier");
    Recording.Add("identifier", "name", "value");
    return Verify(Recording.Stop("identifier"));
}

^{snippet source | anchor}

Results in:

[
  {
    name: value
  }
]

^{snippet source | anchor}

Case is ignored

[Fact]
public Task Case()
{
    Recording.Start();
    Recording.Add("name", "value1");
    Recording.Add("Name", "value2");
    return Verify("TheValue");
}

^{snippet source | anchor}

Results in:

{
  target: TheValue,
  name: value1,
  Name: value2
}

^{snippet source | anchor}

Stop

Recording can be stopped and the resulting data can be manually verified:

[Fact]
public Task Stop()
{
    Recording.Start();
    Recording.Add("name1", "value1");
    Recording.Add("name2", "value2");
    var appends = Recording.Stop();
    return Verify(appends.Where(_ => _.Name != "name1"));
}

^{snippet source | anchor}

Results in:

[
  {
    name2: value2
  }
]

^{snippet source | anchor}

If Stop is called, the results are not automatically verified:

[Fact]
public Task StopNotInResult()
{
    Recording.Start();
    Recording.Add("name1", "value1");
    Recording.Add("name2", "value2");
    Recording.Stop();
    return Verify("other data");
}

^{snippet source | anchor}

Results in:

other data

^{snippet source | anchor}

IsRecording

The status of Recording can be checked.

[Fact]
public void IsRecording()
{
    Assert.False(Recording.IsRecording());
    Recording.Start();
    Assert.True(Recording.IsRecording());
}

^{snippet source | anchor}

This can be helpful if the cost of capturing data, to add to recording, is high.

Clear

The current recorded items can be cleared:

[Fact]
public Task Clear()
{
    Recording.Start();
    Recording.Add("name1", "value1");
    Recording.Clear();
    Recording.Add("name2", "value2");
    return Verify();
}

^{snippet source | anchor}

Results in:

{
  name2: value2
}

^{snippet source | anchor}

Pause and Resume

Recording can be paused and resumed:

[Fact]
public Task PauseResume()
{
    Recording.Start();
    Recording.Pause();
    Recording.Add("name1", "value1");
    Recording.Resume();
    Recording.Add("name2", "value2");
    Recording.Pause();
    Recording.Add("name3", "value3");
    return Verify();
}

^{snippet source | anchor}

Results in:

{
  name2: value2
}

^{snippet source | anchor}

Extensions that leverage Recording