SeleniumDomSnapshot 1.0.0

SeleniumDomSnapshot

Captures and diffs DOM snapshots during Selenium test runs. When a test breaks with NoSuchElementException or an unexpected state, this library shows you exactly what changed in the page structure between the passing baseline and the failing run.

Packages

Quick Start

1. Install

<PackageReference Include="SeleniumDomSnapshot" Version="1.0.0" />
<PackageReference Include="SeleniumDomSnapshot.NUnit" Version="1.0.0" />

2. Add the attribute

using SeleniumDomSnapshot.NUnit;

[Test]
[DomSnapshot(baselineOnPass: true)]
public void Login_RedirectsToDashboard()
{
    driver.Navigate().GoToUrl("https://your-app.com/login");
    // ... test code ...
    Assert.That(driver.Url, Contains.Substring("dashboard"));
}

On the first passing run a baseline is saved. On any failing run the current DOM is captured and a colour-coded HTML diff report is written showing exactly what changed.

3. Manual control (more flexibility)

var snapshots = new DomSnapshotManager("dom_snapshots", ignorePatterns: new[]
{
    DomSnapshotManager.IgnorePatterns.IsoTimestamps,
    DomSnapshotManager.IgnorePatterns.ReadableTimestamps,
    DomSnapshotManager.IgnorePatterns.CspNonces,
    // your own app-specific patterns:
    // @"data-session=[a-zA-Z0-9]+",
});

snapshots.SaveBaseline(driver, "checkout_page");

// ... do stuff ...

snapshots.SaveCurrent(driver, "checkout_page");
DomDiffResult diff = snapshots.Diff("checkout_page");
Console.WriteLine(diff.ToReport());

// colour-coded HTML report — open in browser
string htmlPath = snapshots.SaveHtmlDiffReport("checkout_page");

Ignore Patterns

No patterns are applied by default. Opt in to exactly what your app needs:

DomSnapshotManager.IgnorePatterns.IsoTimestamps      // 2026-01-01T12:00:00
DomSnapshotManager.IgnorePatterns.ReadableTimestamps // 2026-01-01 12:00:00
DomSnapshotManager.IgnorePatterns.CspNonces          // nonce="abc123..."
DomSnapshotManager.IgnorePatterns.CacheBusters       // ?_=1234567890
DomSnapshotManager.IgnorePatterns.CsrfTokens         // csrf-token="..."
DomSnapshotManager.IgnorePatterns.SessionIds         // session-id="..."

You can also pass any custom regex string alongside these.

CI Integration

var ci = new CiArtifactHelper(snapshots, "dom_snapshots");
ci.WriteCiSummary();                    // writes ci_summary.txt, GitHub Actions annotations
ci.ExportSnapshotDirectoryToEnvironment(); // sets SELENIUM_SNAPSHOT_DIR env var
ci.PrintArtifactPaths();               // prints all file paths for CI to pick up

GitHub Actions — upload snapshots as artifacts on failure:

- name: Upload DOM diff reports
  if: failure()
  uses: actions/upload-artifact@v3
  with:
    name: dom-diff-reports
    path: '**/dom_snapshots/**'

Jenkins:

post { failure { archiveArtifacts artifacts: '**/dom_snapshots/**', allowEmptyArchive: true } }