You should first install gridtest. This will place the executable gridtest in your bin folder, which is the client for generating and running tests.

Getting Started


Writing Tests

Running Tests

How does it work?

GridTest takes advantage of the inspect module in Python so that you can provide any Python file, local, or system installed module and extract not only a list of functions and classes, but also arguments. By way of providing a file, module name, or folder path, GridTest can first generate for you a “test template,” which comes down to a yaml file that you can easily fill in and customize for your tests. For example, I might generate a test yaml file for my script like this:

$ gridtest generate gridtest.yml

And you would then open the file and customize the default template to your liking. The testing file can then be run, in the same way, using gridtest:

$ gridtest test gridtest.yml

Or since gridtest.yml is the default, just leave it out to find the file in the present working directory:

$ gridtest test

The tests are run in parallel with multiprocessing to be efficient, but if you want you can specify running in serial:

$ gridtest test --serial

Along with testing the conditions that you specify in the testing file, GridTest will also run type checking if you have defined types in your code. You can also check if you need to add more tests:

# exit code is 0 if all tests written, 1 otherwise
$ gridtest check gridtest.yml

No new tests to add!✨ 🥑️ ✨

And if there are new tests (meaning new functions or classes in the file that aren’t tested) you can update your testing file with those missing:

$ gridtest update gridtest.yml

If you don’t care about testing, you can use GridTest to generate a yaml specification of parameterizations. Let’s say we have a set of grids defined in grids.yml. We can list the named grids that are defined in the file:

$ gridtest gridview grids.yml --list

And then either print them all to the screen:

$ gridtest gridview grids.yml

or just print a specific grid we found with --list.

$ gridtest gridview grids.yml generate_by_min_max
{'x': 0.0}
{'x': 2.0}
{'x': 4.0}
{'x': 6.0}
{'x': 8.0}

For larger grids, it’s nice to be able to get a count. The “twovars” variant of the function above adds another variable (also with 5 values) so we get 5x5:

$ $ gridtest gridview grids.yml generate_by_min_max_twovars --count
25 lists produced.

The rest of this getting started guide will review overall functionality. You should look at tutorials if you have never done this before, and would like to walk through basic examples.

What are gridtest concepts


A gridtest is a yaml file that is executed using the software described here, GridTest. It’s called a GridTest because of the ability to define grids of tests. For example, let’s say that we want to measure the time it takes to run a function over a set of variables. We do this by way of adding an optimization, which comes down to a decorator function that will measure the value and return it to gridtest. We then might specify a range of numbers for one or more function variables. This will ultimately generate a grid of tests for the function, each with a set of results from the function itself and decorators. GridTest also will make it easy to run over a grid of different environments, although this is not developed yet.


GridTest’s main convention is that it will look for a yaml file, gridtest.yml to run tests by default. This means that if you write your testing file in the root of a repository with Python software like:

You can easily run gridtest test in the root of that folder to discover the file. This is similar to a Dockerfile, or Singularity recipe file.


Gridtest does parameterization by way of grids, which is a section of the gridtest.yml (alongside tests) that has definitions for one or more named grids. For example, if we wanted to use a function (script.get_pokemon_id) to generate a list of values for the argument pid for a test called script.generate_pokemon, we might write a recipe like this.

  filename: /home/vanessa/Desktop/Code/gridtest/examples/grid-function/
      func: script.get_pokemon_id
      count: 10

          pid: generate_pids

The reference to “generate_pids” for the argument “pid” is referenced under grids, and we know to use the scripts.get_pokemon_id, run 10 times, to generate it. We could also define arguments for the parameterization. For a simple example, see the grid-function example, or read more in the getting started templates guide.


For most testing frameworks, when you hit an error there is a flash of red across the screen, and at best you can stop execution on the first error (e.g., with pytest you would add the -x flag) or add print statements to the test to see what might be going on. You might start an interactive shell to import modules and functions needed to debug, and then need to exit and run again to re-run the test. Instead of these approaches, gridtest gives you an ability to run a test with --interactive, meaning that you can open an interactive shell at the onset of each test.

$ gridtest test examples/basic/script-tests.yml --interactive
[script.add:1/6] |=====|-----------------------------|  16.7% 

Gridtest interactive mode! Press Control+D to cycle to next test.

   func: <function add at 0x7fe4c0a44200>
 module: <module 'script' from '/home/vanessa/Desktop/Code/gridtest/examples/basic/'>
   args: {'one': 1, 'two': 2}
returns: 3

How to test
passed, error = test_types(func, args, returns)
result = func(**args)

Python 3.7.4 (default, Aug 13 2019, 20:35:49) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.8.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]:                                                                     

In the example above, we show that the function, module, and arguments for the test are loaded, and you are shown how to run the tests. If you have added any decorators (optimizations to measure) they will be applied already to the variable func. By way of having the interactive terminal, you can of course interact with functions and variables directly, and debug what might be the issue for a test. In the case of a file with multiple tests (the typical case) You can also specify the name of the test you want to interact with:

$ gridtest test examples/basic/script-tests.yml --interactive --name script.add

For the above, this would interact with all tests that start with script.add. If you want to limit to the script.add module, you might want to do:

$ gridtest test examples/basic/script-tests.yml --interactive --name script.add.

Or a specific indexed text for the module:

$ gridtest test examples/basic/script-tests.yml --interactive --name script.add.0

For a more detailed debugging example, see the debugging documentation.


This code is licensed under the Mozilla, version 2.0 or later LICENSE.

You might next want to browse tutorials available.