扩展规格

让我们直接开始。

import org.specs._

object ArithmeticSpec extends Specification {
  "Arithmetic" should {
    "add two numbers" in {
      1 + 1 mustEqual 2
    }
    "add three numbers" in {
      1 + 1 + 1 mustEqual 3
    }
  }
}

Arithmetic（算术） 是一个 规范约束下的系统

add（加） 是一个上下文。

add two numbers（两个数相加），和 add three numbers（三个数字相加） 是例子。

mustEqual 表示 预期

1 mustEqual 1 是编写实际测试前使用的一种常见的预期占位符。所有的测试用例都应该至少有一个预期。

复制

注意到两个测试都是怎样将 add 加在其名称中的吗？我们可以通过嵌套预期摆脱这种重复。

import org.specs._

object ArithmeticSpec extends Specification {
  "Arithmetic" should {
    "add" in {
      "two numbers" in {
        1 + 1 mustEqual 2
      }
      "three numbers" in {
        1 + 1 + 1 mustEqual 3
      }
    }
  }
}

object ExecSpec extends Specification {
  "Mutations are isolated" should {
    var x = 0
    "x equals 1 if we set it." in {
      x = 1
      x mustEqual 1
    }
    "x is the default value if we don't change it" in {
      x mustEqual 0
    }
  }
}

Setup, Teardown

doBefore & doAfter

"my system" should {
  doBefore { resetTheSystem() /** user-defined reset function */ }
  "mess up the system" in {...}
  "and again" in {...}
  doAfter { cleanThingsUp() }
}

doFirst & doLast

doFirst/doLast 用来做一次性的设置。（需要例子，我不使用这个）

"Foo" should {
  doFirst { openTheCurtains() }
  "test stateless methods" in {...}
  "test other stateless methods" in {...}
  doLast { closeTheCurtains() }
}

Matchers

你有数据，并且想要确保它是正确的。让我们看看最常用的匹配器是如何帮助你的。

mustEqual

我们已经看到几个 mustEqual 的例子了。

1 mustEqual 1

"a" mustEqual "a"

引用相等，值相等。

序列中的元素

val numbers = List(1, 2, 3)

numbers must contain(1)
numbers must not contain(4)

numbers must containAll(List(1, 2, 3))
numbers must containInOrder(List(1, 2, 3))

List(1, List(2, 3, List(4)), 5) must haveTheSameElementsAs(List(5, List(List(4), 2, 3), 1))

映射中的元素

map must haveKey(k)
map must notHaveKey(k)

map must haveValue(v)
map must notHaveValue(v)

数字

a must beGreaterThan(b)
a must beGreaterThanOrEqualTo(b)

a must beLessThan(b)
a must beLessThanOrEqualTo(b)

a must beCloseTo(b, delta)

Options

a must beNone

a must beSome[Type]

a must beSomething

a must beSome(value)

throwA

a must throwA[WhateverException]

这是一个针对try\catch块中有异常抛出的用例的简写。

您也可以期望一个特定的消息

a must throwA(WhateverException("message"))

a must throwA(new Exception) like {
  case Exception(m) => m.startsWith("bad")
}

编写你自己的匹配器

import org.specs.matcher.Matcher

"A matcher" should {
  "be created as a val" in {
    val beEven = new Matcher[Int] {
      def apply(n: => Int) = {
        (n % 2 == 0, "%d is even".format(n), "%d is odd".format(n))
      }
    }
    2 must beEven
  }
}

契约是返回一个包含三个值的元组，分别是期望是否为真、为真时的消息和为假时的消息。

作为一个样本类

case class beEven(b: Int) extends Matcher[Int]() {
  def apply(n: => Int) =  (n % 2 == 0, "%d is even".format(n), "%d is odd".format(n))
}

Mocks

import org.specs.Specification
import org.specs.mock.Mockito

class Foo[T] {
  def get(i: Int): T
}

object MockExampleSpec extends Specification with Mockito {
  val m = mock[Foo[String]]

  m.get(0) returns "one"

  m.get(0)

  there was one(m).get(0)

  there was no(m).get(1)
}

参考 Using Mockito

Spies

Spies（间谍）可以对真正的对象做一些“局部 mocking”：

val list = new LinkedList[String]
val spiedList = spy(list)

// methods can be stubbed on a spy
spiedList.size returns 100

// other methods can also be used
spiedList.add("one")
spiedList.add("two")

// and verification can happen on a spy
there was one(spiedList).add("one")

// if the list is empty, this will throws an IndexOutOfBoundsException
spiedList.get(0) returns "one"

doReturn("one").when(spiedList).get(0)

在 sbt 中运行单个 specs

> test-only com.twitter.yourservice.UserSpec

> ~ test-only com.twitter.yourservice.UserSpec