get started: add some docs for tidb's integration test

src/get-started/introduction.md

@@ -7,4 +7,5 @@ Let's start your TiDB journey! There's a lot to learn, but every journey starts
 * [Setup an IDE](setup-an-ide.md)
 * [Write and run unit tests](write-and-run-unit-tests.md)
 * [Debug and profile](debug-and-profile.md)
+* [Run and debug integration tests](run-and-debug-integration-tests.md)
 * [Commit code and submit a pull request](commit-code-and-submit-a-pull-request.md)

src/get-started/run-and-debug-integration-tests.md

@@ -0,0 +1,41 @@
+# Run and debug integration tests
+
+TiDB now has some integration tests inside the folder `tests/integrationtest`. Those tests are simply organized as SQL files. The test inputs are put in the folder `t/` and the pre-stored result files are in the folder `r/`.
+
+# How to run integration tests
+
+Once you have built a TiDB binary. You can go to the folder `tests/integrationtest` and run `./run-tests.sh -s ../../bin/tidb-server` to run all the integration tests.
+
+And you can use `-t` to specify a test file to test. If you run `./run-tests.sh -s ../../bin/tidb-server -t executor/simple`, the scripts will run the tests inside the file `t/executor/simple.test`.(It's corresponding result file is `r/executor/simple.result`)
+
+If you find out that the changes of tests are expected, you can pass `-r` to re-generate the result file. If you run `./run-tests.sh -s ../../bin/tidb-server -r executor/simple`, it will overwirte the `r/executor/simple.test` by the new binary.
+
+# How to debug integration tests
+
+Sometimes you will need to debug the test when you find out that some changes are not expected. You will need to do some preparation before attach to `dlv` if you prefer to use `dlv` to do live debugging.
+
+We use some build tags to inject some check in the testing environment. Those tags are `intest,deadlock,integrationtest`, so you need to pass `--tags intest,deadlock,integrationtest` when you're building the binary. Or you can directly run `make server_check` to build the needed binary and then use `dlv` to do the debugging.
+
+After you build the correct binary, you can follow the descriptions in [Use delve for debugging](./debug-and-profile.md#use-delve-for-debugging) to debug TiDB.
+
+## How to use IDE to debug
+
+If you're using IDEs, you'll need to create a special build file for it.
+
+### Visual Studio Code
+
+Find the `Run and Debug` in the left sidebar. If you haven't created any config, click the `create a launch.json file.`
+
+![VS Code create debug file](../img/vscode-go-to-edit.png)
+
+And then you are able to create different run&debug configurations.
+
+![VS Code config sample](../img/vscode-debug-config.png)
+
+The above image shows some samples of the configuration. And the `tidb-on-2432-integration-test` is the one enabling build tags.
+
+Then you just need to click the run button, VS Code will build the binary and then use `dlv` to attach on it.
+
+![VS Code begin debugging](../img/vscode-debug-binary.png)
+
+You can find more about VS Code's debugging on its official documents.

src/get-started/write-and-run-unit-tests.md

@@ -269,3 +269,4 @@ If a test case takes longer, its failure report looks like:
 [2021-08-09T03:33:57.661Z] PASS: tidb_test.go:874: tidbTestSerialSuite.TestTLS  7.388s
 [2021-08-09T03:33:57.661Z] --- PASS: TestCluster (5.20s)
 ```
+And for integration tests, please refer to [Run and debug integration tests](./run-and-debug-integration-tests.md)