--- title: Fortran - Testing - Showing progress and printing results description: This post demonstrates building a custom test framework in Fortran by implementing a polymorphic observer pattern for test progress reporting. It shows how to... canonical: https://daily.dev/posts/fortran---testing---showing-progress-and-printing-results-hr3hrq2s8 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Fortran - Testing - Showing progress and printing results | daily.dev og:description: This post demonstrates building a custom test framework in Fortran by implementing a polymorphic observer pattern for test progress reporting. It shows how to... og:url: https://daily.dev/posts/fortran---testing---showing-progress-and-printing-results-hr3hrq2s8 og:image: https://api.daily.dev/og/posts/HR3Hrq2s8.png og:image:alt: Fortran - Testing - Showing progress and printing results 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. # Fortran - Testing - Showing progress and printing results **[Matthias Noback](https://daily.dev/sources/matthiasnoback)** · 7 min read · 0 upvotes · 0 comments ## Summary This post demonstrates building a custom test framework in Fortran by implementing a polymorphic observer pattern for test progress reporting. It shows how to centralize output control by creating an abstract progress printer type with deferred procedures, allowing different implementations while maintaining clean separation between test execution and result presentation. The tutorial covers extracting interfaces, creating abstract base types, implementing concrete subtypes, and using polymorphism to make output formatting customizable and testable. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Fortran - Testing - Unit tests and test suites](https://daily.dev/posts/fortran---testing---unit-tests-and-test-suites-lsy5kj9un) · Matthias Noback · 0 upvotes · 0 comments - [Fortran - Testing - Improving temporary test programs](https://daily.dev/posts/fortran---testing---improving-temporary-test-programs-6pcwovvdd) · Matthias Noback · 0 upvotes · 0 comments - [Fortran - Testing - Towards a generic, testable test runner](https://daily.dev/posts/fortran---testing---towards-a-generic-testable-test-runner-hydk4tgry) · Matthias Noback · 0 upvotes · 0 comments - [Fortran - Testing - Improving the design of the test framework - Part 2](https://daily.dev/posts/fortran---testing---improving-the-design-of-the-test-framework---part-2-zmkthgyqn) · Matthias Noback · 0 upvotes · 0 comments - [Let’s Build a Unit Testing Library From Scratch](https://daily.dev/posts/let-s-build-a-unit-testing-library-from-scratch-kbtssyqva) · Medium · 0 upvotes · 0 comments --- Tags: [#design-patterns](https://daily.dev/tags/design-patterns), [#fortran](https://daily.dev/tags/fortran), [#general-programming](https://daily.dev/tags/general-programming), [#testing](https://daily.dev/tags/testing) [View this post on daily.dev](https://daily.dev/posts/fortran---testing---showing-progress-and-printing-results-hr3hrq2s8) ```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":"Fortran - Testing - Showing progress and printing results","url":"https://daily.dev/posts/fortran---testing---showing-progress-and-printing-results-hr3hrq2s8","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/fortran---testing---showing-progress-and-printing-results-hr3hrq2s8"},"datePublished":"2026-01-22T16:48:47.788Z","dateModified":"2026-04-10T02:12:36.651Z","description":"This post demonstrates building a custom test framework in Fortran by implementing a polymorphic observer pattern for test progress reporting. 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