From codeplex 9955
https://nmodel.codeplex.com/workitem/9955

From NModel Codeplex 3662 was worked around instead of fixed.

An action term created in the stepper and passed to the model from a class implementing the IStepper interface sometimes reaches the model with modified values. The action sometimes gets replaced in the WeakCache with an earlier instantiation of arguments. The error sometimes occurs on .Net but did not occur with the same code on Mono.

Sadly, the NModel issue doesn't have an example reproduction.

From NModel codeplex 3020

(Pairwise Independent Combinatorial Testing) for parameter space state reduction.

From NModel codeplex 3255

Apparently, loading models from more than one assembly can cause this kind of issue.
This was worked around but not fixed in codeplex.

into the solution

Issue 5158 from NModel.codeplex.com:

Run failed. Object reference not set to an instance of an object.
at NModel.Conformance.ConformanceTester.AddMetricsToEndOfLog() in c:\programs
\NModel\src\NModel\Conformance\ConformanceTesterMetrics.cs:line 70

AddMetricsToEndOfLog calls sw.WriteLine(")") but should use WriteLine(sw,")")

Create test assemblies for the samples to ensure that all of the files continue to work as expected:

• Bag
• Chat
• ClientServer
• Composition
• EmptyCoffeeMachine
• FutureMarket
• GML Examples
• Graphics
• NewsReader
• NFA
• Payroll
• Reactive
• RevisionControl
• Robot
• RPS
• Scheduler
• SP
• Symmetries
• WebApplication

NOTE: WebApplication's implementation is currently a PHP web app. 😦

The Sample solutions are currently .Net 2.0 old versions of the solutions, they need to be updated.

• Bag
• Chat
• ClientServer
• Composition
• EmptyCoffeeMachine
• FutureMarket
• GML Examples
• Graphics
• NewsReader
• NFA
• Payroll
• Reactive
• RevisionControl
• Robot
• RPS
• Scheduler
• SP
• Symmetries
• WebApplication

From Nmodel issue 5152

I'm using mp2dot which was compiled by gmcs - Mono C# compiler version 2.4.2.3 on a Ubuntu Karmic Koala installation - Linux kernel 2.6.31.16: mp2dot /dot:editor.dot /r:Test.dll Editor.Factory.Create, where Test.dll was compiled by the same gmcs.

mp2dot doesn't throw any error. But:

The output file editor.dot then contains a line break which throws an error in the graphviz dot-tools dot, neato and also in xdot. (ErrorMessage.txt in the zip)

Might be minor but it seems to me to be a bug.

zip: Test.cs contains the model program, States.cs the state variable definitions referred to by Test.cs

They may or may not be too similar to NModel's builtin StrategyWithCoverage.

From codeplex 3301:

I have noticed that state variables don't get updated when an object is deleted.
In the attached sample please check a state that comes after a removal of an Employee object, for instance node #66 (around the middle of the fsm). You can see that 'AllEmployees' only contains Employee(2) but 'myCompany' contains also Employee(1) and Employee(3).