[易学易懂系列|rustlang语言|零基础|快速入门|（29）|实战6：BDD工具cucumber_rust]

项目实战

实战6：BDD工具cucumber_rust

今天我们来学习下BDD行为驱动测试工具cucumber_rust。

关于BDD,可以简单看看这些介绍：

https://www.cnblogs.com/superhin/p/11454716.html\#bdd%E4%BB%8B%E7%BB%8D

https://www.jianshu.com/p/0389360ac58f

https://www.infoq.cn/article/2011/02/BDD-ATDD

简单来说，BDD是一种更好，更直观的一种测试驱动开发方法 。

它也是TDD的一种。

它也是遵守如下开发流程：

我们今天要学习的cucumber_rust,是BDD的rust语言版本：

好吧，我们现在开始。

先用命令创建工程：

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1cargo new bdd_with_cucumber

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然后，我们在文件Cargo.toml加入依赖:

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1[[test]]

2name = "cucumber"

3harness = false # Allows Cucumber to print output instead of libtest

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5[dev-dependencies]

6cucumber = { package = "cucumber_rust", version = "^0.6.0" } 

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在当前工程目录下创建目录：tests和features,目录结构如下 ：

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1bdd_with_cucumber

2├── Cargo.lock

3├── Cargo.toml

4├── tests

5├── features

6├── src

7│   └── main.rs

8└── target

9    └── debug

10        └── ...

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我们在tests目录下，创建文件：cucumber.rs,加入如下代码：

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1use cucumber::{cucumber, steps, before, after};

2

3pub struct MyWorld {

4    // You can use this struct for mutable context in scenarios.

5    foo: String

6}

7

8impl cucumber::World for MyWorld {}

9impl std::default::Default for MyWorld {

10    fn default() -> MyWorld {

11        // This function is called every time a new scenario is started

12        MyWorld { 

13            foo: "a default string".to_string()

14        }

15    }

16}

17

18mod example_steps {

19    use cucumber::steps;

20    

21    // Any type that implements cucumber::World + Default can be the world

22    steps!(crate::MyWorld => {

23        given "I am trying out Cucumber" |world, step| {

24            world.foo = "Some string".to_string();

25            // Set up your context in given steps

26        };

27

28        when "I consider what I am doing" |world, step| {

29            // Take actions

30            let new_string = format!("{}.", &world.foo);

31            world.foo = new_string;

32        };

33

34        then "I am interested in ATDD" |world, step| {

35            // Check that the outcomes to be observed have occurred

36            assert_eq!(world.foo, "Some string.");

37        };

38

39        then regex r"^we can (.*) rules with regex$" |world, matches, step| {

40            // And access them as an array

41            assert_eq!(matches[1], "implement");

42        };

43

44        then regex r"^we can also match (\d+) (.+) types$" (usize, String) |world, num, word, step| {

45            // `num` will be of type usize, `word` of type String

46            assert_eq!(num, 42);

47            assert_eq!(word, "olika");

48        };

49

50        then "we can use data tables to provide more parameters" |world, step| {

51            let table = step.table().unwrap().clone();

52

53            assert_eq!(table.header, vec!["key", "value"]);

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55            let expected_keys = table.rows.iter().map(|row| row[0].to_owned()).collect::<Vec<_>>();

56            let expected_values = table.rows.iter().map(|row| row[1].to_owned()).collect::<Vec<_>>();

57

58            assert_eq!(expected_keys, vec!["a", "b"]);

59            assert_eq!(expected_values, vec!["fizz", "buzz"]);

60        };

61    });

62}

63

64// Declares a before handler function named `a_before_fn`

65before!(a_before_fn => |scenario| {

66

67});

68

69// Declares an after handler function named `an_after_fn`

70after!(an_after_fn => |scenario| {

71

72});

73

74// A setup function to be called before everything else

75fn setup() {

76    

77}

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79cucumber! {

80    features: "./features", // Path to our feature files

81    world: crate::MyWorld, // The world needs to be the same for steps and the main cucumber call

82    steps: &[

83        example_steps::steps // the `steps!` macro creates a `steps` function in a module

84    ],

85    setup: setup, // Optional; called once before everything

86    before: &[

87        a_before_fn // Optional; called before each scenario

88    ], 

89    after: &[

90        an_after_fn // Optional; called after each scenario

91    ] 

92}

93

然后，我们在目录：features下创建文件：example.feature，加入如下代码：

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1Feature: Example feature

2

3    Scenario: An example scenario

4        Given I am trying out Cucumber

5        When I consider what I am doing

6        Then I am interested in ATDD

7        And we can implement rules with regex

8

然后，我们运行命令：

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1cargo test --test cucumber

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运行结果如下：

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1

2Feature: Example feature

3 \\?\E:\code\rustProject\bdd_with_cucumber_rust\features\example.feature:1:1

4

5 Scenario: An example scenario

6 \\?\E:\code\rustProject\bdd_with_cucumber_rust\features\example.feature:3:15

7  ✔ Given I am trying out Cucumber

8 \\?\E:\code\rustProject\bdd_with_cucumber_rust\features\example.feature:4:9

9  ✔ When I consider what I am doing

10 \\?\E:\code\rustProject\bdd_with_cucumber_rust\features\example.feature:5:9

11  ✔ Then I am interested in ATDD

12 \\?\E:\code\rustProject\bdd_with_cucumber_rust\features\example.feature:6:9

13  ✔ And we can implement rules with regex

14 \\?\E:\code\rustProject\bdd_with_cucumber_rust\features\example.feature:7:9

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161 features

171 scenarios (1 passed)

184 steps (4 passed)

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以上，希望对你有用。

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1如果遇到什么问题，欢迎加入：rust新手群，在这里我可以提供一些简单的帮助，加微信：360369487，注明：博客园+rust

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github地址：https://github.com/gyc567/bdd_with_cucumber_rust/tree/master

https://blog.testlodge.com/what-is-bdd/

https://cucumber.io/

https://www.agilealliance.org/glossary/bdd/