tasty-mgolden: Golden testing provider for tasty with muti-line diff output

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Please visit the README at https://github.com/mbj/tasty-mgolden#readme for usage information.

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Versions [RSS] 0.0.1, 0.0.2
Dependencies ansi-terminal (>=0.9 && <0.11), base (>=4.12 && <=4.15), Diff (==0.3.4 || >=0.4 && <0.5), filepath (>=1.4.2 && <1.5), tasty (>=1.3.1 && <1.4), tasty-expected-failure, tasty-hunit, tasty-mgolden, text (>=1.2 && <1.3) [details]
License BSD-3-Clause
Author Markus Schirp <mbj@schirp-dso.com>
Maintainer Markus Schirp <mbj@schirp-dso.com>
Category Testing
Home page https://github.com/mbj/tasty-mgolden#readme
Bug tracker https://github.com/mbj/tasty-mgolden/issues
Source repo head: git clone https://github.com/mbj/tasty-mgolden
Uploaded by mbj at 2020-09-27T01:50:19Z
Reverse Dependencies 1 direct, 1 indirect [details]
Executables tasty-mgolden-example
Downloads 349 total (5 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2020-09-27 [all 1 reports]

Readme for tasty-mgolden-0.0.2

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Text based golden tests for tasty, with multi line (colored) diff expectation failure reporting.

Basically this package can turn any IO Text action into a golden test via providing a FilePath.

This package is the small brother of tasty-golden which also implements the same golden testing pattern.

tasty-mgolden is less generic and more opinionated than its bigger brother. But for that reason can also offer more ergonomic defaults for its core use case:

Golden testing for IO Text actions. Where:

  • The text value is assuemd to contain multiple lines.
  • The expectation failures can be rendered nicely in multi line diffs.
  • The diff lines are colored via the tasty infrastructure
  • The diff rendering is not done via the external diff command, but uses the Diff package.

Expectation diffs are rendered like developers are used to:

  • Removed lines rendered in red.
  • Added lines in green.


This is taken from the example directory in the repository.

To run these execute from repository root:

stack build
stack exec tasty-mgolden-example

Contents of example/example-a.txt


Contents of example/example-b.txt


Contents: example/Test.hs

import Test.Tasty
import Test.Tasty.MGolden

main :: IO ()
main = defaultMain $ testGroup "golden tests"
  [ goldenTest "example-a" "example/example-a.txt" $ pure "foo\nbar\n"
  , goldenTest "example-b" "example/example-b.txt" $ pure "foo\nbaz\n"


golden tests
  example-a: OK
  example-b: FAIL

1 out of 2 tests failed (0.00s)

Passing the --update flag to accept the changes:

golden tests
  example-a: OK
  example-b: OK

All 2 tests passed (0.00s)


PRs on these are welcome.

  • Improve the multi line diff reporting to only show a minimal context around the changed hunks.
  • Add line markers in unified diff format.
  • Change to pathtype from filepath
  • Future? Upstream this to tasty-golden ?