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在Groovy / Spock断言中，不执行调用方法

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在使用Spock的Groovy单元测试中，以下任务非常常见：

assert myResult == calculateExpectedResult() （带或不带 assert 关键字 . ）

groovy断言打印出大量关于这里发生的事情的信息，以及为什么我的断言失败了 . 但是当比较的对象非常复杂和深度时，它可能会变得棘手，所以获得未通过测试的具体属性 .

为此，我发现Javers Framework做了一个很好的工作比较对象和产生一个精确的差异 . 我创建了一个特性来做到这一点：

trait DiffTrait {

  Javers javers = JaversBuilder.javers().build()

  String diff(result, expected) {
    Diff diff = javers.compare(result, expected);
    def valueChanges = diff.getChangesByType(ValueChange)
    String message = ""
    valueChanges.each { message += "\n$it.propertyName = $it.left instead of expected: $it.right" }
    return message
  }
}

现在我可以在我的单元测试中使用它，如下所示：

def expected = calculateExpectedResult()
assert myResult == expected, diff(myResult, expected)

通过这种方式，我得到了一个很好的打印差异列表 .

但这有点冗长，因为我必须指定两次值 .

所以我改变了这样的特征：

trait DiffTrait {

  Javers javers = JaversBuilder.javers().build()

  def result

  def expected

  String diff(result, expected) {
    Diff diff = javers.compare(result, expected);
    def valueChanges = diff.getChangesByType(ValueChange)
    String message = ""
    valueChanges.each { message += "\n$it.propertyName = $it.left instead of expected: $it.right" }
    return message
  }

  String diff() {
    diff(result, expected)
  }

  def result(result) {
    this.result = result
    return result
  }

  def expected(expected) {
    this.expected = expected
    return expected
  }
}

想法是这样使用它：

def result = callTheSystemToProduceTheRealResult()
def expected = calculateExpectedResult()
assert result(myResult) == expected(expected), diff()

但令人惊讶的是，这不起作用！这两个属性为null，diff方法因NotNull-Exception而失败 . 如果我调试此代码，则永远不会调用 expected / result 方法！

如果我像这样重写代码

def result = result(callTheSystemToProduceTheRealResult())
def expected = expected(calculateExpectedResult())
assert myResult == expected, diff()

一切都按预期工作 . 正确调用方法并设置属性 .

我的问题是：为什么我不能在assert语句中调用这些方法？这两个代码片段的Groovy / Spock视角有什么区别？

这是一个包含所有代码作为运行示例的gist .

groovy spock

1 回答

  • 3

    这很容易解释 . 在断言本身之前评估断言消息 . 以下代码完美无缺，但它显示静态 diff 消息：

    import org.javers.core.Javers
import org.javers.core.JaversBuilder
import org.javers.core.diff.Diff
import org.javers.core.diff.changetype.ValueChange
import spock.lang.Specification

class LolSpec extends Specification implements DiffTrait {

    def 'lol'() {
        expect:
        def whatIGot = new Lol(l: 'a')
        def whatIExpected = new Lol(l: 'b')
        assert result(whatIGot) == expected(whatIExpected), 'diff'
    }

}

trait DiffTrait {

    Javers javers = JaversBuilder.javers().build()

    def result
    def expected

    String diff() {
        diff(result, expected)
    }

    String diff(result, expected) {
        Diff diff = javers.compare(result, expected);
        def valueChanges = diff.getChangesByType(ValueChange)
        String message = ""
        valueChanges.each { message += "\n$it.propertyName = $it.left instead of expected: $it.right" }
        return message
    }

    def result(result) {
        this.result = result
        return result
    }

    def expected(expected) {
        this.expected = expected
        return expected
    }
}

class Lol {
    String l
}

    您需要传递两次参数或更改实现，例如：

    import groovy.transform.EqualsAndHashCode
import org.javers.core.Javers
import org.javers.core.JaversBuilder
import org.javers.core.diff.changetype.ValueChange
import spock.lang.Specification

class LolSpec extends Specification {

    def 'lol'() {
        expect:
        def whatIGot = new Lol(l: 'a')
        def whatIExpected = new Lol(l: 'b')
        def diff = new Diff(result: whatIGot, expected: whatIExpected)
        assert diff.check(), diff.message()
    }

}

class Diff {

    Javers javers = JaversBuilder.javers().build()

    def result
    def expected

    String message() {
        def diff = javers.compare(result, expected);
        def valueChanges = diff.getChangesByType(ValueChange)
        String message = ""
        valueChanges.each { message += "\n$it.propertyName = $it.left instead of expected: $it.right" }
        return message
    }

    boolean check() {
        result.equals(expected)
    }

}

@EqualsAndHashCode
class Lol {
    String l
}
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