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我目前正在尝试习惯 TDD，并且在我正在从事的当前项目中，我正在尝试利用 AWS 的 Go SDK。这一切都很好，花花公子，我以前用过它，但我目前正在尝试模拟*ec2.DescribeVolumesOutput发送的值。

深入研究代码，我认为这是返回的内容*ec2.DescribeVolumesOutput：

type DescribeVolumesOutput struct {
    _ struct{} `type:"structure"`

    // The NextToken value to include in a future DescribeVolumes request. When
    // the results of a DescribeVolumes request exceed MaxResults, this value can
    // be used to retrieve the next page of results. This value is null when there
    // are no more results to return.
    NextToken *string `locationName:"nextToken" type:"string"`

    // Information about the volumes.
    Volumes []*Volume `locationName:"volumeSet" locationNameList:"item" type:"list"`
}

好的..这很酷，但是我想模拟的输出必须存在于Volumes []*VolumelocationName:"volumeSet" locationNameList:"item" type:"list"` 所以让我们再深入一点，看看那是什么......

type Volume struct {
    _ struct{} `type:"structure"`

    // Information about the volume attachments.
    Attachments []*VolumeAttachment `locationName:"attachmentSet" locationNameList:"item" type:"list"`

    // The Availability Zone for the volume.
    AvailabilityZone *string `locationName:"availabilityZone" type:"string"`

    // The time stamp when volume creation was initiated.
    CreateTime *time.Time `locationName:"createTime" type:"timestamp"`

    // Indicates whether the volume will be encrypted.
    Encrypted *bool `locationName:"encrypted" type:"boolean"`

    // The number of I/O operations per second (IOPS) that the volume supports.
    // For Provisioned IOPS SSD volumes, this represents the number of IOPS that
    // are provisioned for the volume. For General Purpose SSD volumes, this represents
    // the baseline performance of the volume and the rate at which the volume accumulates
    // I/O credits for bursting. For more information, see Amazon EBS Volume Types
    // (https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html)
    // in the Amazon Elastic Compute Cloud User Guide.
    //
    // Constraints: Range is 100-16,000 IOPS for gp2 volumes and 100 to 64,000IOPS
    // for io1 volumes, in most Regions. The maximum IOPS for io1 of 64,000 is guaranteed
    // only on Nitro-based instances (https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html#ec2-nitro-instances).
    // Other instance families guarantee performance up to 32,000 IOPS.
    //
    // Condition: This parameter is required for requests to create io1 volumes;
    // it is not used in requests to create gp2, st1, sc1, or standard volumes.
    Iops *int64 `locationName:"iops" type:"integer"`

    // The full ARN of the AWS Key Management Service (AWS KMS) customer master
    // key (CMK) that was used to protect the volume encryption key for the volume.
    KmsKeyId *string `locationName:"kmsKeyId" type:"string"`

    // The size of the volume, in GiBs.
    Size *int64 `locationName:"size" type:"integer"`

    // The snapshot from which the volume was created, if applicable.
    SnapshotId *string `locationName:"snapshotId" type:"string"`

    // The volume state.
    State *string `locationName:"status" type:"string" enum:"VolumeState"`

    // Any tags assigned to the volume.
    Tags []*Tag `locationName:"tagSet" locationNameList:"item" type:"list"`

    // The ID of the volume.
    VolumeId *string `locationName:"volumeId" type:"string"`

    // The volume type. This can be gp2 for General Purpose SSD, io1 for Provisioned
    // IOPS SSD, st1 for Throughput Optimized HDD, sc1 for Cold HDD, or standard
    // for Magnetic volumes.
    VolumeType *string `locationName:"volumeType" type:"string" enum:"VolumeType"`
}

好的！这看起来像一些我想模拟其值的数据！

但在过去的几天里，我没有真正嘲笑这些价值观。他们是否如此嵌套以至于这种类型的嘲笑不值得努力？即使尝试使用github.com/aws/aws-sdk-go/service/ec2/ec2iface似乎也无法帮助我理解如何正确打包一些模拟值返回以进行测试。我在 TDD 上错了吗？我错过了一些非常明显的东西吗？我真的没有示例代码可以显示，因为我现在不再了解我想要做什么。

有没有人可能有一个他们如何嘲笑这个的例子？

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1 回答 1

3

无法模拟类型，您只能模拟接口的实现。在您的情况下，我假设您正在尝试调用DescribeVolumes并在响应中获取您构造的值。
为此，您需要创建一个模拟

type MockEC2API struct {
    ec2iface.EC2API // embedding of the interface is needed to skip implementation of all methods
    DescribeVolumesMethod func(*ec2.DescribeVolumesInput) (*ec2.DescribeVolumesOutput, error)
}

func (m *MockEC2API) DescribeVolumes(in *ec2.DescribeVolumesInput) (*ec2.DescribeVolumesOutput, error) {
    if m.DescribeVolumesMethod != nil {
        return m.DescribeVolumesMethod(in)
    }
    return nil, nil // return any value you think is good for you
}

在测试中创建实例MockEC2API而不是真实实例，ec2.EC2并为其提供将被调用并返回您准备好的ec2.DescribeVolumesOutput结果的函数

...
ec2 := &MockEC2API{
    DescribeVolumesMethod: func(*ec2.DescribeVolumesInput) (*ec2.DescribeVolumesOutput, error) {
        return &ec2.DescribeVolumesOutput{...your initialization...}, nil
    }
}
...
output, err := ec2.DescribeVolumes(in) // this output will be your prepared initialization
于 2019-05-29T21:37:50.433 回答