diff --git a/docs/05_Mock_tests.md b/docs/05_Mock_tests.md new file mode 100644 index 0000000..cb43525 --- /dev/null +++ b/docs/05_Mock_tests.md @@ -0,0 +1,57 @@ +# Mock Tests + +A web crawler is by nature dependant on the external service which it is crawling. +In order to have a reliable CI pipeline, this external dependency needs to be removed. +For this there is a system in place to automatically save the requests made to a service and their responses. +These can then be used in CI to reliably test changes made to the Extractor and not have test failures due to API changes on the side of the service. + +## Multiple downloader implementations + +There are multiple implementations of the abstract class `Downloader` + +1. `DownloaderTestImpl` is used for running the test against the actual service. +2. `RecordingDownloader` is used the save the request and response to the disk, thus creating the mock. +3. `MockDownloader` is used to answer requests with the saved mocks. + +### Usage + +There are 2 ways to specify which downloader should be used. + +First one is passing the `-Ddownloader=` argument from the command line, where `value` can be one of +[DownloaderType](https://github.com/TeamNewPipe/NewPipeExtractor/blob/dev/extractor/src/test/java/org/schabi/newpipe/downloader/DownloaderType.java) +. The main usecase is in the CI pipeline like this: `./gradlew check --stacktrace -Ddownloader=MOCK`. +Other than that it can also be used to mass generate mocks by specifying which package should be tested. As example if +one wanted to update all YouTube mocks: +`gradle clean test --tests 'org.schabi.newpipe.extractor.services.youtube.*' -Ddownloader=RECORDING` + +The second way is changing the field `DownloaderFactory.DEFAULT_DOWNLOADER`. +The default value is `DownloaderType.REAL` which should be changed on the master branch. +Locally one can change this to `DownloaderType.RECORDING`, run the tests and commit +the generated mocks. +This is the main use case for when developing locally. + +### Mock only tests + +There are some things which cannot ever be tested reliably against an actual service. +For example tests for an upcoming livestream would fail, after the livestream was started. + +For this there is a marker interface `MockOnly` and a custom TestRule `MockOnlyRule`. +It skips the tests in the CI pipeline if they are not run with mocks. + +See `MockOnlyRule` for further details. + +Example usage: + +``` java +public static class TestClass { + + @Rule + public MockOnlyRule rule = new MockOnlyRule(); + + @MockOnly + @Test + public void myTest() throws Exception { + //assertions + } +} +``` \ No newline at end of file diff --git a/docs/05_releasing.md b/docs/06_releasing.md similarity index 100% rename from docs/05_releasing.md rename to docs/06_releasing.md diff --git a/docs/06_documentation.md b/docs/07_documentation.md similarity index 100% rename from docs/06_documentation.md rename to docs/07_documentation.md diff --git a/docs/07_maintainers_view.md b/docs/08_maintainers_view.md similarity index 100% rename from docs/07_maintainers_view.md rename to docs/08_maintainers_view.md