microsoft/coyote

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Coyote is a library and tool for testing concurrent C# code and deterministically reproducing bugs.

Stars: 1.6k
Forks: 92
Open beginner issues: 0
Indexed issues: 34
Avg merge: 44m
Merged PRs (30d): 1

Dominant language: C#
License: No license data
Last GitHub push: Aug 24, 2026
Latest indexed: Sep 19, 2026
Contributing guide: No contributing guide
Code of conduct: Code of conduct
Beginner labels: No beginner labels indexed

Beginner friendly Everything

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34 open issues indexed

Support for .NET 9 Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/coyote#521 · 9 comments · 16 reactions · Opened Aug 18, 2025
Release 1.7.12/1.8.0 Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

microsoft/coyote#518 · Opened Apr 25, 2025
Support library mode for rewriting for situations where multiple target frameworks are needed. Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/coyote#517 · Opened Apr 16, 2025
Actor Disposal Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

microsoft/coyote#516 · Opened Feb 21, 2025
"Object reference not set to an instance of an object" when running the rewriter. Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/coyote#506 · Opened Jun 25, 2024
System.NullReferenceException when using Timer in test class Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

microsoft/coyote#504 · Opened Apr 13, 2024
Unable to load one or more of the requested types Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

microsoft/coyote#491 · 1 reaction · Opened Nov 30, 2023
Deadlock if Interleave point inside a static constructor Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/coyote#488 · Opened Aug 17, 2023
Potential bug with race condition Open

Difficulty 4/5 3-5 days Newbie friendliness 24/100

microsoft/coyote#484 · 4 comments · Opened Jun 24, 2023
Exception when trying to rewrite WPF .NET 6.0 application; unable to find PresentationCore Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/coyote#474 · 5 comments · Opened Apr 15, 2023
race in updating coverage report Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/coyote#464 · Opened Mar 27, 2023
InvalidProgramException while trying coyote on my library. Open

area-binary-rewriting bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/coyote#433 · 13 comments · 1 reaction · Opened Nov 23, 2022
fix send event logs when actor runtime has terminated Open

area-actors bug

Difficulty 3/5 1-2 days Newbie friendliness 35/100

microsoft/coyote#356 · Opened Jul 14, 2022
include the test method name in the schedule file Open

area-systematic-testing

Difficulty 3/5 1-2 days Newbie friendliness 30/100

microsoft/coyote#349 · 1 reaction · Opened Jun 16, 2022
fix compatibility issue with VS Code coverage and assembly rewriting Open

area-binary-rewriting bug

Difficulty 4/5 3-5 days Newbie friendliness 28/100

microsoft/coyote#345 · 3 comments · 1 reaction · Opened Jun 14, 2022
document supported/unsupported Task APIs and synchronization primitives Open

area-documentation

Difficulty 3/5 1-2 days Newbie friendliness 25/100

microsoft/coyote#335 · Opened May 8, 2022
Documentation describing different exploration strategies? Open

area-documentation

Difficulty 3/5 1-2 days Newbie friendliness 35/100

microsoft/coyote#332 · 2 comments · Opened Apr 26, 2022
support best-effort replay with systematic fuzzing Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

microsoft/coyote#309 · Opened Mar 17, 2022
support best-effort replay with partially controlled concurrency Open

area-systematic-testing

Difficulty 5/5 Over a week Newbie friendliness 15/100

microsoft/coyote#308 · Opened Mar 17, 2022
add some logs for deferred events and nothing else on the queue Open

area-actors

Difficulty 3/5 1-2 days Newbie friendliness 35/100

microsoft/coyote#290 · Opened Feb 22, 2022
handle ThreadInterruptedException for aspnet Open

area-runtime bug

Difficulty 4/5 3-5 days Newbie friendliness 25/100

microsoft/coyote#266 · Opened Jan 6, 2022
expose API in testing engine to notify if the test ended due to uncontrolled concurrency Open

area-systematic-testing

Difficulty 5/5 Over a week Newbie friendliness 20/100

microsoft/coyote#261 · Opened Dec 6, 2021
resolve already rewritten types in a dependent assembly Open

area-binary-rewriting

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/coyote#254 · Opened Nov 18, 2021
harden actor queues against reentrancy by the same thread Open

area-actors

Difficulty 4/5 3-5 days Newbie friendliness 15/100

microsoft/coyote#251 · Opened Nov 10, 2021
make sure test setup methods (when multiple) are associated with correct test Open

area-cli

Difficulty 4/5 3-5 days Newbie friendliness 20/100

microsoft/coyote#240 · Opened Oct 18, 2021
give better warnings if tester detects a [Test] method without the appropriate signature Open

area-cli

Difficulty 3/5 1-2 days Newbie friendliness 35/100

microsoft/coyote#238 · 2 comments · Opened Oct 15, 2021
automatically rewrite popular unit testing frameworks Open

area-binary-rewriting

Difficulty 5/5 Over a week Newbie friendliness 25/100

microsoft/coyote#233 · 1 comment · Opened Oct 15, 2021
integration with dotnet test Open

area-cli

Difficulty 5/5 Over a week Newbie friendliness 30/100

microsoft/coyote#232 · 1 reaction · Opened Oct 15, 2021
tester invoke all possible tests Open

area-cli

Difficulty 3/5 1-2 days Newbie friendliness 35/100

microsoft/coyote#231 · 2 comments · 2 reactions · Opened Oct 15, 2021
add sequential portfolio strategy mode Open

area-systematic-testing

Difficulty 5/5 Over a week Newbie friendliness 25/100

microsoft/coyote#230 · Opened Oct 14, 2021
add support for task.Start on an explicit new Task Open

area-binary-rewriting

Difficulty 4/5 3-5 days Newbie friendliness 38/100

microsoft/coyote#191 · Opened Jun 15, 2021
optimize PCT for async tasks continuations Open

area-systematic-testing

Difficulty 5/5 Over a week Newbie friendliness 25/100

microsoft/coyote#169 · Opened May 19, 2021
desktop and iphone UI bugs Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 25/100

microsoft/coyote#152 · 3 comments · Opened Apr 3, 2021
Request for Actors to be notified when the runtime is stopped Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/coyote#36 · Opened Jun 26, 2020

microsoft/coyote

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