en/A0_Tests.ipynb

{"cells": [{"cell_type": "markdown", "metadata": {}, "source": ["##"]}, {"attachments": {}, "cell_type": "markdown", "metadata": {}, "source": ["## Tests\n", "\n", "Every program has to be tested to confirm that it does what you say it does. One way to do this is to run the entire program each time a significant change is made. This working model is clearly very expensive, particularly in the time it takes to perform this procedure over and over again, and it becomes unmanageable as the application grows in complexity.\n", "\n", "For that there are [different types of tests or _tests_](https://programacionymas.com/blog/tipos-de-testing-en-desarrollo-de-software) that can be programmed so that the computer performs them automatically.\n", "\n", "A test essentially consists of running a part of the code with certain data (which can be real or synthetic),\n", "and compare the result of that run with a known one.\n", "\n", "Some of the types of tests used are:\n", "\n", "- Unit tests: where each part of the program is tested in isolation, evaluating different functions, for example.\n", "- Integration test: where the workflow between different components of the system is verified.\n", "- End-to-end test: where the complete user experience is evaluated, defined from the different use cases of the application.\n", "\n", "Modern programming languages \u200b\u200boffer different libraries to be able to write tests. In particular, in the .NET [there are several options](https://learn.microsoft.com/en-us/dotnet/core/testing/) ecosystem:\n", "\n", "- xUnit\n", "- NUnit\n", "- MSTest\n", "- [wait](https://www.codit.eu/blog/the-beautiful-f-expecto-paradigm-think-in-tests-not-frameworks/)\n", "\n", "Next we will see how to add unit tests to our `HelloWorld` example.\n", "\n", "### NUnit\n", "\n", "We will use NUnit to write our tests. To begin with, we create a `tests` directory in the directory where our test is located.\n", "solution:\n", "\n", "```bash\n", "mkdir tests\n", "cd tests \n", "```\n", "> It's not required, but it's good practice for tests to be in their own directory.\n", ">\n", "\n", "with which, our directory structure would look like this:\n", "\n", "```bash\n", ".\n", "\u2514\u2500\u2500 HolaMundo/\n", "    \u251c\u2500\u2500 src/\n", "    \u2502   \u251c\u2500\u2500 MyProject/\n", "    \u2502   \u2514\u2500\u2500 MyLibrary/    \u2502           \n", "    \u2514\u2500\u2500 tests/\n", "    \u2514\u2500\u2500 HolaMundo.sln \n", "```\n", "\n", "Now let's create a NUnit project using:\n", "\n", "```bash\n", "dotnet new nunit -lang F# -o tests/MyTests\n", "```\n", "with which we will have:\n", "```bash\n", ".\n", "\u2514\u2500\u2500 HolaMundo/\n", "    \u251c\u2500\u2500 src/\n", "    \u2502   \u251c\u2500\u2500 MyProject/\n", "    \u2502   \u2514\u2500\u2500 MyLibrary/         \n", "    \u2514\u2500\u2500 tests/\n", "    \u2502   \u2514\u2500\u2500 MyTests/    \n", "    \u2514\u2500\u2500 HolaMundo.sln \n", "```\n", "\n", "> It is possible that initially the test creation takes time, because `dotnet` performs the _restore_ operation. restore\n", "> takes care of updating project dependencies, which may involve searching the cloud for modules that\n", "> are not installed locally.\n", "\n", "Then we can add the test project to the solution:\n", "\n", "```bash\n", "dotnet sln add tests/MyTests/MyTests.fsproj\n", "```\n", "\n", "Like all _templates_, `dotnet` provides us with minimal but functional code when creating the `MyTests` project. If we do\n", "\n", "```bash\n", "/HolaMundo> dotnet test \n", "```\n", "It will run the trivial test proposed by the _template_:\n", "\n", "```fsharp\n", "[<Test>]\n", "let Test1 () =\n", "    Assert.Pass()\n", "```\n", "\n", "You can run `dotnet test` with the `-t` option to see which tests to run:\n", "```bash\n", "/HolaMundo> dotnet test -t\n", "  Determining projects to restore...\n", "  All projects are up-to-date for restore.\n", "  MyLibrary -> /Users/flavioc/Codes/GitHub/HolaMundo/src/MyLibrary/bin/Debug/net7.0/MyLibrary.dll\n", "  MyTests -> /Users/flavioc/Codes/GitHub/HolaMundo/tests/MyTests/bin/Debug/net7.0/MyTests.dll\n", "Test run for /Users/flavioc/Codes/GitHub/HolaMundo/tests/MyTests/bin/Debug/net7.0/MyTests.dll (.NETCoreApp,Version=v7.0)\n", "Microsoft (R) Test Execution Command Line Tool Version 17.4.0 (x64)\n", "Copyright (c) Microsoft Corporation.  All rights reserved.\n", "\n", "The following Tests are available:\n", "    Test1\n", "```\n", "\n", "\n", "As an example, we are going to test some function of our library `MyLibrary`. To do this, we have to notify the project\n", "`MyTests` for library existence:\n", "\n", "```bash\n", "dotnet add tests/MyTests/MyTests.fsproj reference src/MyLibrary/MyLibrary.fsproj \n", "```\n", "\n", "We can write some tests, for example:\n", "\n", "```fsharp\n", "[<Test>]\n", "let ``Suma 2 mas 2`` () = \n", "    let expected = 4\n", "    let actual = add 2 2 \n", "\n", "    Assert.That(expected, Is.EqualTo(actual))\n", "```\n", "\n", "To go beyond case-by-case testing, one can do [property-based tests](https://fsharpforfunandprofit.com/pbt/).\n", "\n"]}], "metadata": {"language_info": {"name": "python"}, "orig_nbformat": 4}, "nbformat": 4, "nbformat_minor": 2}