ADD: add docs

Author: T-K-233

tests/README.md

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+# Chipyard Tests
+
+To build the tests, we do the following procedure.
+
+## Clean the previous build
+
+First, we clean the previous build. This step is recommended when any changes are made to the CMake build flow. This is equivalent to running `make clean` to the CMake build system.
+
+```bash
+cd $chipyard/tests/
+rm -rf ./build/
+```
+
+
+## Configure the CMake build system
+
+Then, we configure the cmake to build with the following settings. This step only needs to be done once when the build directory is not created.
+
+```bash
+cmake -S ./ -B ./build/ -D CMAKE_BUILD_TYPE=Debug
+```
+
+`-S` specifies the source directory, which is the current directory.
+
+`-B` specifies the build directory, which is `./build/`.
+
+`-D CMAKE_BUILD_TYPE=Debug` specifies the build type, which is debug.
+
+
+## Build the tests
+
+Then, we build the tests with the following command.
+
+By default, the target is `all`, which builds all the tests.
+
+```bash
+cmake --build ./build/ --target all
+```
+
+If only specific tests are needed, we can specify the tests by adding the test name after `--target`.
+
+For example, to build the `hello` test, we can run the following command.
+
+```bash
+cmake --build ./build/ --target hello
+``` 
+
+
+## Generating disassembly of the tests
+
+To dump the disassembly of the tests, we can run the following command.
+
+```bash
+cmake --build ./build/ --target dump
+``` 
+
+To dump the disassembly of the `hello` test, we can run the following command.
+
+```bash
+cmake --build ./build/ --target hello_dump
+``` 
+
+## Clean the previous build
+
+To clean the previous build, we can run the following command.
+
+```bash
+cmake --build ./build/ --target clean
+```