Unittest document(#1763)

docs/README.md

@@ -13,8 +13,8 @@ At present, the guide is composed of the following parts:
     1. [Install toolchain](toolchain.md)
     2. [Get the code, build and run](build-and-run.md)
     3. Set up an IDE
-    4. Write and run unit tests
-    5. Debug and profile
+    4. [Write and run unit tests](unittest.md)
+    5. [Debug](debug.md)
     6. Commit code and submit a pull request
 2. **Contribute to OceanBase**: helps you quickly get involved in the OceanBase community, which illustrates what contributions you can make and how to quickly make one.
 

docs/unittest.md

@@ -0,0 +1,102 @@
+# Write and run unittest
+
+## How to build and run all unittest?
+
+[OceanBase](https://github.com/oceanbase/oceanbase) has two unittest directories.
+
+- `unittest` . These are the main unittest cases, and it tests the code in the `src` directory.
+
+- `deps/oblib/unittest`. Cases for oblib.
+
+First, you should build `unittest`. You should enter the `unittest` directory in the build directory and build explicitly. When you build the oceanbase project, it does't build the unittest in default. For example:
+
+```bash
+bash build.sh --init --make # init and build a debug mode project
+cd build_debug/unittest  # or cd build_debug/deps/oblib/unittest
+make -j4 # build unittest
+```
+
+Then you can execute the script file `run_tests.sh` to run all test cases.
+
+## How to build and run a single unittest
+
+You can also build and test a single unittest case. You can enter the `build_debug` directory, and execute `make case-name` to build the specific case and run the binary file built. For example:
+
+```bash
+cd build_debug
+# **NOTE**: don't enter the unittest directory
+make -j4 test_chunk_row_store
+find . -name "test_chunk_row_store"
+# got ./unittest/sql/engine/basic/test_chunk_row_store
+./unittest/sql/engine/basic/test_chunk_row_store
+```
+
+## How to write unittest
+
+As a C++ project, [OceanBase](https://github.com/oceanbase/oceanbase) uses [google test](https://github.com/google/googletest) as the unittest framework. 
+
+OceanBase use `test_xxx.cpp` as the unittest file name. You can create a `test_xxx.cpp` file and add the file name into the specific `CMakeLists.txt` file.
+
+In the `test_xxx.cpp` file, you should add a header file `#include <gtest/gtest.h>` and the main function below.
+
+```cpp
+int main(int argc, char **argv)
+{
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
+```
+
+You can then add some functions to test different scenarios. Below is an example from `test_ra_row_store_projector.cpp`.
+
+```cpp
+///
+/// TEST is a google test macro. 
+/// You can use it to create a new test function
+///
+/// RARowStore is the test suite name and alloc_project_fail
+/// is the test name.
+///
+TEST(RARowStore, alloc_project_fail)
+{
+  ObEmptyAlloc alloc;
+  ObRARowStore rs(&alloc, true);
+
+  /// ASSERT_XXX are some testing macros help us decide the results are 
+  /// expected, and it will terminate the test if failed.
+  ///
+  /// There are some other testing macros begin with `EXPECT_` which 
+  /// don't terminate the test if failed.
+  ///
+  ASSERT_EQ(OB_SUCCESS, rs.init(100 << 20));
+  const int64_t OBJ_CNT = 3;
+  ObObj objs[OBJ_CNT];
+  ObNewRow r;
+  r.cells_ = objs;
+  r.count_ = OBJ_CNT;
+  int64_t val = 0;
+  for (int64_t i = 0; i < OBJ_CNT; i++) {
+    objs[i].set_int(val);
+    val++;
+  }
+
+  int32_t projector[] = {0, 2};
+  r.projector_ = projector;
+  r.projector_size_ = ARRAYSIZEOF(projector);
+
+  ASSERT_EQ(OB_ALLOCATE_MEMORY_FAILED, rs.add_row(r));
+}
+```
+
+Please refer to [google test document](https://google.github.io/googletest/) to get more details about `TEST`, `ASSERT` and `EXPECT`.
+
+
+## Unittest on GitHub CI
+
+Before a pull request is merged, the CI will test your pull request. The `Farm` will test the `mysql test` and `unittest`. You can see the details follow the `Details` link like below.
+
+![github ci](images/unittest-github-ci.png)
+
+![github ci farm details](images/unittest-ci-details.png)
+
+![Farm unittest](images/unittest-unittest.png)