--- title: No more regressions with Snapshot Tests in C# using... description: Snapshot testing captures an entire method's output as a file-based baseline, flagging any unexpected change rather than only the values a developer explicitly... canonical: https://daily.dev/posts/no-more-regressions-with-snapshot-tests-in-c-using-verify-a-practical-guide-tychmwf5g twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: No more regressions with Snapshot Tests in C# using Verify: a practical guide | daily.dev og:description: Snapshot testing captures an entire method's output as a file-based baseline, flagging any unexpected change rather than only the values a developer explicitly... og:url: https://daily.dev/posts/no-more-regressions-with-snapshot-tests-in-c-using-verify-a-practical-guide-tychmwf5g og:image: https://api.daily.dev/og/posts/tycHmWF5G.png og:image:alt: No more regressions with Snapshot Tests in C# using Verify: a practical guide og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # No more regressions with Snapshot Tests in C# using Verify: a practical guide **[Code4IT](https://daily.dev/sources/code4it)** · 17 min read · 0 upvotes · 0 comments ## Summary Snapshot testing captures an entire method's output as a file-based baseline, flagging any unexpected change rather than only the values a developer explicitly asserts. The Verify NuGet library, which integrates with NUnit, xUnit, and MSTest, is used to implement snapshot tests in C# for both data-returning methods and outgoing HTTP payloads. The walkthrough covers first-run baseline creation, approving .verified files, catching unintended field additions or renames, scrubbing dynamic values like timestamps and GUIDs, and verifying full HTTP requests (method, URL, body) via a custom HttpMessageHandler. Snapshot tests are presented as a complement to, not a replacement for, unit and integration tests. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I write a snapshot test in C# using the Verify library? Call Verify(object) on the result of the method under test inside an async test method that returns Task. On the first run the test fails and Verify generates a .received file alongside an empty .verified file; after reviewing the .received output, copy or rename it to .verified to approve it as the baseline. Subsequent runs compare new output against that approved snapshot and fail on any difference. _daily.dev surfaces practical guides like this for developers setting up snapshot testing in their C# test suites._ ### How do I handle dynamic values like timestamps or GUIDs in Verify snapshot tests so they don't break the test every run? DateTime values are scrubbed automatically by Verify and replaced with a placeholder like DateTime_1 in the snapshot. For other dynamic fields, such as a date formatted as a string, use ScrubMember to mark the specific property for scrubbing, for example ScrubMember(p => p.LastPlayedAsString), which replaces its value with {Scrubbed} so the test still passes while confirming the field exists. _developers wiring up flaky-free snapshot tests can find focused walkthroughs like this through daily.dev._ ### How can I verify the exact JSON payload sent in an outgoing HTTP request in a C# unit test without hitting a real server? Use a custom HttpMessageHandler that intercepts the request, captures the request body and HttpRequestMessage, and returns a fake HttpResponseMessage instead of calling a live endpoint. Pass that handler into an HttpClient used by the service under test, then call VerifyJson on the captured body (or Verify on an object combining method, URL, and body) to snapshot-test the exact outgoing payload. _daily.dev helps developers testing outgoing API payloads find concrete patterns like this one._ ## Similar posts on daily.dev - [Master Complex Data Migrations with Snapshot Testing](https://daily.dev/posts/master-complex-data-migrations-with-snapshot-testing-6bil54f0b) · Atomic Spin · 0 upvotes · 0 comments - [Testing can be fun, actually](https://daily.dev/posts/testing-can-be-fun-actually-iorwrxdme) · Lobsters · 0 upvotes · 0 comments - [Security Tests That Prove Themselves — Daily DevOps & .NET](https://daily.dev/posts/security-tests-that-prove-themselves-daily-devops-net-4mutnqllj) · We Are .NET · 1 upvotes · 0 comments - [Snapshot Testing on iOS: A Setup That Actually Stays Green](https://daily.dev/posts/snapshot-testing-on-ios-a-setup-that-actually-stays-green-wxncwpy3s) · Medium · 0 upvotes · 0 comments --- Tags: [#testing](https://daily.dev/tags/testing), [#.net](https://daily.dev/tags/.net), [#c#](https://daily.dev/tags/c#) [View this post on daily.dev](https://daily.dev/posts/no-more-regressions-with-snapshot-tests-in-c-using-verify-a-practical-guide-tychmwf5g) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"No more regressions with Snapshot Tests in C# using Verify: a practical guide","url":"https://daily.dev/posts/no-more-regressions-with-snapshot-tests-in-c-using-verify-a-practical-guide-tychmwf5g","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/no-more-regressions-with-snapshot-tests-in-c-using-verify-a-practical-guide-tychmwf5g"},"datePublished":"2026-10-04T13:06:45.651Z","dateModified":"2026-10-04T13:09:55.891Z","description":"Snapshot testing captures an entire method's output as a file-based baseline, flagging any unexpected change rather than only the values a developer explicitly...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/2ee4936b1cf3a8c82cc78a29f6ca3644?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/2ee4936b1cf3a8c82cc78a29f6ca3644?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Code4IT","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Code4IT","logo":"https://media.daily.dev/image/upload/s--OaaG4G10--/f_auto,q_auto/v1791119049/logos/code4it?_a=BAMAMicg0","url":"https://daily.dev/sources/code4it"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/no-more-regressions-with-snapshot-tests-in-c-using-verify-a-practical-guide-tychmwf5g","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"testing,.net,c#","timeRequired":"PT17M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Code4IT","item":"https://daily.dev/sources/code4it"},{"@type":"ListItem","position":3,"name":"No more regressions with Snapshot Tests in C# using Verify: a practical guide"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/no-more-regressions-with-snapshot-tests-in-c-using-verify-a-practical-guide-tychmwf5g#faq","mainEntity":[{"@type":"Question","name":"How do I write a snapshot test in C# using the Verify library?","acceptedAnswer":{"@type":"Answer","text":"Call Verify(object) on the result of the method under test inside an async test method that returns Task. 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