add readme

Author: ShuiRuTian

editors/code/src/test_explorer/README.md

@@ -45,7 +45,7 @@ For example
 |    |  // omit cargo file
 |    |-tests
 |        |-foo-bar.rs
-|    
+|
 |
 |-package2
 |    |  // omit cargo file
@@ -107,3 +107,122 @@ When you want to run `mod1::foo`(module), the cause will be matched too.
 8. As mentioned in 2 point, "run all" does not work for workspace level for now.
 
 9. Debug will not update the state of test item.(could provide better experience for Linux)
+
+
+###
+
+Init
+
+``` mermaid
+sequenceDiagram
+    participant U as User
+    participant VSC as VSCode
+    participant C as VSCode extension
+    participant RA as Rust Analyzer
+
+    U->>+VSC: Open testing explorer
+    VSC->>+C: resolver sends init request
+    C->>+RA: get cargo project info
+    RA->>-C: back cargo project info
+    C->>C: construct Ideal tree about workspace and package part
+    loop until all targets are got
+    C->>+RA: request test infos for target root files (repeat many times)
+    RA->>-C: request test infos for target root files
+    end
+    C->>C: construct Ideal tree about target root files part
+    C->>C: construct TestItem tree By Ideal tree
+    C->>-VSC: VSCode got the Test Item tree
+    VSC->>-U: Render Test Explorer
+```
+
+Change avtive file
+``` mermaid
+sequenceDiagram
+    participant U as User
+    participant VSC as VSCode
+    participant C as VSCode extension
+    participant RA as Rust Analyzer
+
+    U->>+VSC: Change active document
+    VSC->>+C: trigger event
+    C->>C: check whether the file is already loaded
+    alt is already loaded
+    C->>VSC: nothing changed
+    VSC->>U: nothing changed
+    else file is not loaed
+    Note over C: Load the file, but we might need to load its parent
+    loop until the module is loaded
+    C->>C: find nearest parent of the file module in ideal tree
+    C->>RA: get module info of the file
+    RA->>C: return module info of the file
+    C->>C: add new nodes to ideal tree
+    end
+    C->>C: construct TestItem tree By Ideal tree
+    C->>-VSC: VSCode got the Test Item tree
+    VSC->>-U: Render Test Explorer
+    end
+```
+
+Add file
+Change file
+Delete file
+``` mermaid
+sequenceDiagram
+    participant U as User
+    participant VSC as VSCode
+    participant C as VSCode extension
+    participant RA as Rust Analyzer
+
+    U->>+VSC: Add/Delete/Change file
+    VSC->>+C: trigger event
+    C->>RA: request test info in file
+    RA->>C: back test info in file
+    C->>C: update ideal tree
+    Note over C: This is different for different operations
+    C->>C: construct TestItem tree By Ideal tree
+    C->>-VSC: VSCode got the Test Item tree
+    VSC->>-U: Render Test Explorer
+```
+
+
+Debug
+``` mermaid
+sequenceDiagram
+    participant U as User
+    participant VSC as VSCode
+    participant C as VSCode extension
+    participant LLDB as LLDB extension
+
+    U->>+VSC: Click run/debug button
+    VSC->>+C: testing API trigger event
+    C->>C: compute VSCode Debug configuration(LLDB)
+    C->>C: Set test status for test items
+    C->>VSCode: Start debug
+    VSCode->>LLDB: Debugger protocal
+    LLDB->>VSCode: Debugger protocal
+    VSCode->>C: debug session
+    C->>C: Analytics test output from rustc and update status of test items
+    C->>C: Attach info to test items(if any)
+    C->>-VSC:
+    VSC->>-U:
+```
+
+Run
+``` mermaid
+sequenceDiagram
+    participant U as User
+    participant VSC as VSCode
+    participant C as VSCode extension
+    participant Cargo as Cargo
+
+    U->>+VSC: Click run/debug button
+    VSC->>+C: testing API trigger event
+    C->>C: compute Cargo command
+    C->>C: Set test status for test items
+    C->>Cargo: execute commands
+    Cargo->>C: run tests
+    C->>C: Analytics test output from rustc and update status of test items
+    C->>C: Attach info to test items(if any)
+    C->>-VSC:
+    VSC->>-U:
+```