Long time viewer, first time questioner here. Using Unit Tests in a separate project, I can't figure out how to separate them at the release build?
Surely when I remove the reference to the Unit Test project, all the references to the Unit Test interfaces, won't be able to find the interfaces and will cause compiler errors?
Thanks for any help.
Edit: By separating I mean removing them on the release build.
Assuming .NET, your unit test project should have a reference to the production project - but not the other way round. Your production code shouldn't depend on your unit tests at all.
You should have built your two projects, so that the base code (That in which you are testing) has no dependencies on the unit test. It is the Unit Test that has the dependencies on your code.
From what you wrote, I gather you wrote your code in .NET? (i.e. Assemblies?). Your project dependencies should look like this.
// Business code
My_Project.dll
-> References
---> System.dll etc..
// Test code
My_Project_Test.dll
-> References
---> My_Project.dll
If you make your projects that way, than I think you won't have to do anything special in your release build configuration.
Related
We had a unit test project (exe, using NUnitLite) that referenced the main application to unit test code within the main application (an exe).
This used to work, but now Xamarin is giving an error that we can't reference an exe project.
Why is this?
What alternatives do people suggest for unit testing application code? It seems wrong to have to move all application code from the exe to an assembly just for the purposes of unit testing.
It looks like the feature was accidentally removed :-( Someone must have overlooked that valid, if uncommon, scenario. Please file a bug report on Xamarin.Studio and request this feature to be *re*enabled.
Until then I see two workarounds:
Build/execute the tests from a script (e.g. a Makefile). You can automate this to require less steps than using the IDE;
Add a pre-build step to your project to make a copy of the .exe and name it .dll. Then reference this copy of the assembly.
We develop a C++ application using Visual Studio 2008 and unit test using Boost.Test. At the moment, we have a separate solution which contains our unit tests.
Many of our projects in the core solution produce DLL's. We're limited in test coverage because we cannot test non-exported classes.
I have two ideas on how these could be tested:
Export everything
Put the tests inside the DLL (same project and solution) and use Boost.Test's external runner
I'm not entirely sure what the drawbacks would be. Number 1 above breaks module level encapsulation, and number 2 could result in a much larger DLL, unless it's possible to only include the test code in certain configurations.
So, are there any severe drawbacks to the above methods, or can you think of other solutions?
Expanding on Tom Quarendon's answer to this question, I have used a slight variant of Simon Steele's response:
Create a test project (using whatever test framework you like, I use CppUnit).
In your test_case.cpp, #include <header/in/source/project.h>.
In the test project properties:
In Linker->General, add the source project's $(IntDir) to the Additional Library Directories.
In Linker->Input, add the .obj files to the Additional Dependencies.
Add the dependency from the test project to the source project in Project->Project Dependencies.
Again, the only maintenance overhead is the standard one for unit tests - to create the dependency on the unit(s) you want to test.
The solution I use for this is to build the same non-exported code into my tests DLL as well. This does increase build time and means adding everything to both projects, but saves exporting everything or putting the tests in the main product code.
Another posibility would be to compile the non-exported code into a lib which is used by both the DLL with exports, and the unit test project.
Was searching a solution as well, maybe the following will be easier to maintain.
Add a new build configuration e.g. "Unit testing Debug" to the DLL project and change the Configuration Type to be "Static Library .lib" ("General"->"Configuration Type").
Then just add a dependency of your unit tests on this project, now everything should link together when you use new build configuration "Unit testing Debug".
If you are using release builds for unit tests then you need to add another configuration with release optimizations.
So the benefits of this solution are:
low maintanability cost
single DLL/Static library project
don't have to manually link to .obj files
Drawbacks:
Extra configuration profile(s) will require some changes in your build environment (CI)
Greater compilation times
Update:
We actually ended up using a different approach.
We added new "Test debug"/"Test release' configurations for every existing project that we have.
For .exe/.dll projects we disable the original main.cpp from compiling and replaced it with the one that instantiates the test framework (e.g. gtest) and runs all the tests, the tests are in separate .cpp files which are also excluded from compilation in regular configurations (Release/Debug) and enabled only in Test configurations.
For .lib projects we also have new "Test debug"/"Test release" configurations and there we convert the static library to be an .exe file and provide a main.cpp which instantiates the testing framework and runs the tests and tests themselves. Test related files are excluded from compilation on Release/Debug configurations.
Try making a define such as the following somewhere all files will include:
#define EXPORTTESTING __declspec(dllexport)
And use it in place of the dllexport, like this:
class EXPORTTESTING Foo
{
...
};
Then you will be able to turn off the flag for building a release DLL, but keep it on for a unit-testable DLL.
I'm just getting started with TDD and am curious as to what approaches others take to run their tests. For reference, I am using the google testing framework, but I believe the question is applicable to most other testing frameworks and to languages other than C/C++.
My general approach so far has been to do one of three things:
Write the majority of the application in a static library, then create two executables. One executable is the application itself, while the other is the test runner with all of the tests. Both link to the static library.
Embed the testing code directly into the application itself, and enable or disable the testing code using compiler flags. This is probably the best approach I've used so far, but clutters up the code a bit.
Embed the testing code directly into the application itself, and, given certain command-line switches either run the application itself or run the tests embedded in the application.
None of these solutions are particularly elegant...
How do you do it?
Your approach no. 1 is the way I've always done it in C/C++ and Java. Most of the application code is in the static library and I try to keep the amount of extra code needed for the application to a minimum.
The way I approach TDD in Python and other dynamic languages is slightly different in that I leave the source code for the application and tests lying around and a test runner finds the tests and runs them.
I tend to favour static libs over dlls so most of my C++ code ends up in static libs anyway and, as you've found, they're as easy to test as dlls.
For code that builds into an exe I either have a separate test project which simply includes the source files that are under test and that are usually built into the exe OR I build a new static lib that contains most of the exe and test that in the same way that I test all of my other static libs. I find that I usually take the 'most code in a library' approach with new projects and the 'pull the source files from the exe project into the test project' approach when I'm retro fitting tests to existing applications.
I don't like your options 2 and 3 at all. Managing the build configurations for 2 is probably harder than having a separate test project that simply pulls in the sources it needs and including all of the tests into the exe as you suggest in 3 is just wrong ;)
I use two approaches, for dlls I just link my unit tests with the dll, easy. For executables I include the source files that are being tested in both the executable project and the unit test project. This adds slightly to the build time but means I don't need to separate the executable in to a static lib and a main function.
I use boost.test for unit testing and cmake to generate my project files and I find this the easiest approach. Also I am slowly introducing unit-testing to a large legacy code base so I am trying to introduce the least amount of changes, in case I inconvenience other developers and discourage them from unit testing. I would worry that using a static library just for unit testing might be seen as an excuse not adopt it.
Having said this, I think the static library approach is a nice one especially if you are starting from scratch.
For C/C++ apps I try to have as much code as possible in one or more dlls, with the main application being the bare minimum to start-up and hand-off to the dll. Dlls are much easier to test because they can export as many entry points as I like for a test application to use.
I use a seperate test application that links to the Dll(s). I'm strongly in favour of keeping test code and "product" code in seperate modules.
I go with #1, some reasons are
It allows to check that each lib links correctly
You don't want extra code in the product
It's easier to debug individual small test programs
You may need multiple executables for some tests (like communication tests)
For C++ build and test, I like to use CMake which can run a selection of the target executables as tests and print a summary of the results.
Personnally, I use another approach that relies a bit on yours:
I keep the project-to-test intact. If it's an executable, it should stay an executable. You simply create a post build action in order to aggregate all obj files into a static library.
Then, you can create you test project, linking the test framework and your previously generated static library.
Here are some topics corresponding to your question:
Visual Studio C++: Unit test exe project with google test?
Linker error - linking two "application" type projects in order to use Google Test
I'm using a third-party test-runners with their framework and including testing in build script. Tests are outside of production code (external dll).
I recently received as a new task to maintain and improve existing code written in C++ with MS Visual Studio. The code builds into an exe file (not a dll). I would like to add unit tests for the code and the problem I encountered is how to organize my testing projects. Basically I want to have 2 projects, one would be the original project I received and the second the testing project.
I saw on the Internet that usually when the subject being tested is built into a dll it's quite easy you have to statically link in your testing project the lib built from the main project and you have access to the function being tested. But how can this be done when the subject under test is an exe file?
Surely you can arrange the solution into projects that share code, where one project outputs to exe and the other(s) to DLL?
Whatever the project deliverable is, unit testing is testing the smallest units: the functions. A unit test typically follows the tripe A pattern: Arrange (create the environment for the test), Act (invoke the method under test), Assert (verify the method behaved as expected).
There are several possible project[s] structures: modify the project so that it compiles into a DLL, a production executable and a unit test program. The executable source has to be as small as possible, possibly just the main() function that create an Application object. It is also possible to have three projects, one for the DLL, one for the application and the third one for the tests.
An alternative is to embed the unit tests inside the executable and to have a mean to invoke them, e.g. with a special --unit-test parameter.
My question is quite relevant to something asked before but I need some practical advice.
I have "Working effectively with legacy code" in my hands and I 'm using advice from the book as I read it in the project I 'm working on. The project is a C++ application that consists of a few libraries but the major portion of the code is compiled to a single executable. I 'm using googletest for adding unit tests to existing code when I have to touch something.
My problem is how can I setup my build process so I can build my unit tests since there are two different executables that need to share code while I am not able to extract the code from my "under test" application to a library. Right now I have made my build process for the application that holds the unit tests link against the object files generated from the build process of the main application but I really dislike it. Are there any suggestions?
Working Effectively With Legacy Code is the best resource for how to start testing old code. There are really no short term solutions that won't result in things getting worse.
I'll sketch out a makefile structure you can use:
all: tests executables
run-tests: tests
<commands to run the test suite>
executables: <file list>
<commands to build the files>
tests: unit-test1 unit-test2 etc
unit-test1: ,files that are required for your unit-test1>
<commands to build unit-test1>
That is roughly what I do, as a sole developer on my project
If your test app is only linking the object files it needs to test then you are effectively already treating them as a library, it should be possible to group those object files into a separate library for the main and the test app. If you can't then I don't see that what you are doing is too bad an alternative.
If you are having to link other object files not under test then that is a sign of dependencies that need to be broken, for which you have the perfect book.
We have similar problems and use a system like the one suggested by Vlion
I personally would continue doing as you are doing or consider having a build script that makes the target application and the unit tests at the same time (two resulting binaries off the same codebase). Yes it smells fishy but it is very practical.
Kudos to you and good luck with your testing.
I prefer one test executable per test. This enables link-time seams and also helps allow TDD as you can work on one unit and not worry about the rest of your code.
I make the libraries depend on all of the tests. Hopefully this means your tests are only run when the code actually changes.
If you do get a failure the tests will interrupt the build process at the right place.