<h2>ch11. Testing</h2> - HackMD

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width: 34px !important; height: 21px !important; border: none !important; float: right; margin-top: -7px; margin-right: -10px; } .my-icon-css { width: 100%; height: 200px; background-position:center; background-repeat: no-repeat; background-image:url('https://mir-s3-cdn-cf.behance.net/project_modules/disp/fe36cc42774743.57ee5f329fae6.gif'); } </style>  # <h2>ch11. Testing</h2> <div class="my-icon-css"></div> @Kais(VagrantPi) ###### tags: `Rust`, `簡報`, `Rust 讀書會` ---  ## Agenda - Writing tests - Runung tests - Test Organization ---  ## Writing tests ---- ### assert_eq!、assert_ne!  ```rust #[cfg(test)] mod tests { #[test] fn it_works() { assert_eq!(2 + 2, 4); } } ``` ----  ``` $ cargo test Compiling adder v0.1.0 (file:///projects/adder) Finished dev [unoptimized + debuginfo] target(s) in 0.22 secs Running target/debug/deps/adder-ce99bcc2479f4607 running 1 test test tests::it_works ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out Doc-tests adder running 0 tests test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ``` ----  ``` test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ``` - passed: 通過測試 - failed: 未通過 - ignored: 忽略 - measured: 性能測試（benchmark tests），目前只有 Rust 開發版（nightly Rust）才有 - filtered out: 過濾、忽略的 ----  ### assert! ```rust #[derive(Debug)] pub struct Rectangle { length: u32, width: u32, } impl Rectangle { pub fn can_hold(&self, other: &Rectangle) -> bool { self.length > other.length && self.width > other.width } } #[cfg(test)] mod tests { // tests mod 如需測試外部 mod 就需要引入，這裡選擇全局導入 // 以便使用全部外部 mod 定義的內容 use super::*; #[test] fn larger_can_hold_smaller() { let larger = Rectangle { length: 8, width: 7 }; let smaller = Rectangle { length: 5, width: 1 }; assert!(larger.can_hold(&smaller)); } #[test] fn smaller_cannot_hold_larger() { let larger = Rectangle { length: 8, width: 7 }; let smaller = Rectangle { length: 5, width: 1 }; assert!(!smaller.can_hold(&larger)); } } ``` ``` running 2 tests test tests::smaller_cannot_hold_larger ... ok test tests::larger_can_hold_smaller ... ok test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ``` ----  ### 自訂錯誤訊息 ```diff pub fn greeting(name: &str) -> String { - format!("Hello {}!", name) + String::from("Hello!") } #[cfg(test)] mod tests { use super::*; #[test] fn greeting_contains_name() { let result = greeting("Carol"); assert!(result.contains("Carol")); } } ``` ----  ``` running 1 test test tests::greeting_contains_name ... FAILED failures: ---- tests::greeting_contains_name stdout ---- thread 'tests::greeting_contains_name' panicked at 'assertion failed: result.contains("Carol")', src/lib.rs:12:8 note: Run with `RUST_BACKTRACE=1` for a backtrace. failures: tests::greeting_contains_name ``` ----  ```rust #[test] fn greeting_contains_name() { let result = greeting("Carol"); assert!( result.contains("Carol"), "Greeting did not contain name, value was `{}`", result ); } ``` ----  ``` ---- tests::greeting_contains_name stdout ---- thread 'tests::greeting_contains_name' panicked at 'Greeting did not contain name, value was `Hello!`', src/lib.rs:12:8 note: Run with `RUST_BACKTRACE=1` for a backtrace. ``` ----  ### should_panic ```rust pub struct Guess { value: u32, } impl Guess { pub fn new(value: u32) -> Guess { if value < 1 || value > 100 { panic!("Guess value must be between 1 and 100, got {}.", value); } Guess { value } } } #[cfg(test)] mod tests { use super::*; #[test] #[should_panic] fn greater_than_100() { Guess::new(200); } } ``` ``` running 1 test test tests::greater_than_100 ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ``` ----  ### should_panic(expected="...") ```rust pub struct Guess { value: u32, } impl Guess { pub fn new(value: u32) -> Guess { if value < 1 { panic!("Guess value must be greater than or equal to 1, got {}.", value); } else if value > 100 { panic!("Guess value must be less than or equal to 100, got {}.", value); } Guess { value } } } #[cfg(test)] mod tests { use super::*; #[test] #[should_panic(expected = "Guess value must be less than or equal to 100")] fn greater_than_100() { Guess::new(200); } #[test] #[should_panic(expected = "Guess value must be greater than or equal to 1")] fn less_than_1() { Guess::new(0); } } ``` ---  ## Runung tests ----  ## 並行執行 ``` $ cargo test -- --test-threads=1 ``` ----  ## 顯示函示輸出 ```rust fn prints_and_returns_10(a: i32) -> i32 { println!("I got the value {}", a); 10 } #[cfg(test)] mod tests { use super::*; #[test] fn this_test_will_pass() { let value = prints_and_returns_10(4); assert_eq!(10, value); } #[test] fn this_test_will_fail() { let value = prints_and_returns_10(8); assert_eq!(5, value); } } ``` ----  ``` running 2 tests test tests::this_test_will_pass ... ok test tests::this_test_will_fail ... FAILED failures: ---- tests::this_test_will_fail stdout ---- I got the value 8 thread 'tests::this_test_will_fail' panicked at 'assertion failed: `(left == right)` left: `5`, right: `10`', src/lib.rs:19:8 note: Run with `RUST_BACKTRACE=1` for a backtrace. failures: tests::this_test_will_fail test result: FAILED. 1 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out ``` 如果連成功的都要輸出，可以使用 ``` $ cargo test -- --nocapture ``` ----  ### 只跑單個測試 ```rust pub fn add_two(a: i32) -> i32 { a + 2 } #[cfg(test)] mod tests { use super::*; #[test] fn add_two_and_two() { assert_eq!(4, add_two(2)); } #[test] fn add_three_and_two() { assert_eq!(5, add_two(3)); } #[test] fn one_hundred() { assert_eq!(102, add_two(100)); } } ``` ----  ``` $ cargo test one_hundred Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs Running target/debug/deps/adder-06a75b4a1f2515e9 running 1 test test tests::one_hundred ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 2 filtered out ``` ----  ### 只跑過濾過的多個測試 ``` $ cargo test add Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs Running target/debug/deps/adder-06a75b4a1f2515e9 running 2 tests test tests::add_two_and_two ... ok test tests::add_three_and_two ... ok test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 1 filtered out ``` ----  ### 忽略某些測試 ```rust #[test] fn it_works() { assert_eq!(2 + 2, 4); } #[test] #[ignore] fn expensive_test() { // code that takes an hour to run } ``` ----  ``` $ cargo test Compiling adder v0.1.0 (file:///projects/adder) Finished dev [unoptimized + debuginfo] target(s) in 0.24 secs Running target/debug/deps/adder-ce99bcc2479f4607 running 2 tests test expensive_test ... ignored test it_works ... ok test result: ok. 1 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out ``` ----  也可以只跑 ignored 的測試 ``` $ cargo test -- --ignored Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs Running target/debug/deps/adder-ce99bcc2479f4607 running 1 test test expensive_test ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 1 filtered out ``` ---  ## Test Organization ----  ## 單元測試（unit tests） ----  ### 測試 module 與 cfg(test) - `#[cfg(test)]` 註解用來告訴 Rust 只在執行 `cargo test` 時才測試，在 `cargo build` 不會做 - cfg 属性代表 configuration，用來告訴 Rust 編譯或執行時的設定 ----  ### 測試私有函數 src/lib.rs ```rust pub fn add_two(a: i32) -> i32 { internal_adder(a, 2) } fn internal_adder(a: i32, b: i32) -> i32 { a + b } #[cfg(test)] mod tests { use super::*; #[test] fn internal() { assert_eq!(4, internal_adder(2, 2)); } } ``` ----  ## 整合測試（integration tests） ----  需要在專案根目錄建立 `tests` 目錄 tests/integration_test.rs ```rust // adder 為整個專案的名稱 // 在單元測試中不用寫，不過整合測試中 // 每個 tests 底下的測試檔案都是獨立的 crate // 所以需要將所每一個檔案都引入 extern crate adder; // 這裡不需要 #[cfg(test)] #[test] fn it_adds_two() { assert_eq!(4, adder::add_two(2)); } ``` ----  ``` $ cargo test Compiling adder v0.1.0 (file:///projects/adder) Finished dev [unoptimized + debuginfo] target(s) in 0.31 secs Running target/debug/deps/adder-abcabcabc running 1 test test tests::internal ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out Running target/debug/deps/integration_test-ce99bcc2479f4607 running 1 test test it_adds_two ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out Doc-tests adder running 0 tests test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ``` 輸出的三個部分分別為：單元測試、整合測試、文件測試 ----  ### 只執行指定的整合測試只跑 tests/integration_test.rs 中的測試 ``` $ cargo test --test integration_test Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs Running target/debug/integration_test-952a27e0126bb565 running 1 test test it_adds_two ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ``` ----  ### 整合測試中的子 module tests/common.rs ```rust pub fn setup() { // setup code specific to your library's tests would go here } ``` ----  ``` running 1 test test tests::internal ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out Running target/debug/deps/common-b8b07b6f1be2db70 running 0 tests test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out Running target/debug/deps/integration_test-d993c68b431d39df running 1 test test it_adds_two ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out Doc-tests adder running 0 tests test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ``` ``` 測試時不希望測試到 common.rs，我們只希望在其他整合測試時用到它 tests/common.rs -> tests/common/mod.rs ``` ----  tests/integration_test.rs ```rust extern crate adder; mod common; #[test] fn it_adds_two() { common::setup(); assert_eq!(4, adder::add_two(2)); } ``` ---  ## Thanks for listening ~