按时在Visual Studio中覆盖代码

Question

我在Visual Studio 2013中编写单元测试，但代码覆盖率分析遇到问题。 语言为C＃，并使用默认的Microsoft.VisualStudio.TestTools.UnitTesting。

if (exsistingNode.NodeState > NodeState.Edit)
{
    if (existingNode.NodeName != updatedNode.NodeName)
    {
        throw m_Diagnostics.ThrowCannotUpdateAfterEditState(subject, existingNode.NodeId, "NodeName");
    }
    if (existingNode.StartDate != updatedNode.StartDate)
    {
        throw m_Diagnostics.ThrowCannotUpdateAfterEditState(subject, existingNode.NodeId, "StartDate");
    }
    if (existingNode.Description != updatedNode.Description)
    {
        throw m_Diagnostics.ThrowCannotUpdateAfterEditState(subject, existingNode.NodeId, "Description");
    }
}

我已经为每个if语句进行了单元测试。 我的第一个成功的单元测试通过了所有这些测试，并且没有引发错误，然后我有三个单独的单元测试，分别测试每个if语句并引发错误。 我的问题是代码分析显示以下语句：

if (existingNode.StartDate != updatedNode.StartDate)

因为仅进行了部分测试，我无法理解为什么。 这是因为它需要时间吗？

在下面的代码中也是如此，其中代码覆盖了引发，但是部分if语句覆盖了所有代码。

if (updatedNode.StartDate != existingNode.StartDate)
{
    if (updatedNode.StartDate.HasValue && updatedNode.StartDate < DateTime.Now)
    {
        throw m_Diagnostics.ThrowUpdateNodeException(subject, existingNode.NodeId, new InvalidOperationException("Cannot set the start date less than now."));
    }

    if (updatedNode.StartDate.HasValue && updatedNode.EndDate.HasValue && updatedNode.EndDate < updatedNode.StartDate)
    {
        throw m_Diagnostics.ThrowUpdateNodeException(subject, existingNode.NodeId, new InvalidOperationException("Cannot set the end date less than the start date."));
    }
}

if (updatedNode.EndDate != existingNode.EndDate)
{
    if (updatedNode.EndDate.HasValue && updatedNode.EndDate < DateTime.Now)
    {
        throw m_Diagnostics.ThrowUpdateNodeException(subject,  existingNode.NodeId, new InvalidOperationException("Cannot set the end date lessthan now."));
    }

有人要求提供单元测试的一些示例。 接下来是与第一种情况有关的两个。 如果您在其他情况下需要它们，请告诉我。

[TestMethod] // Start Date Test that is only Partially covered
[ExpectedException(typeof(Exception))]
public void ChangeStartDate() // Unit Test where the Start Date is changed when not in Edit Mode
{
    //Arrange
    Node nodeToUpdate = new Node
    {
        NodeName = "nodeName",
        StartDate = DateTime.Now.AddDays(1),
        NodeState = NodeState.Open
    };
    collectionNode.Add(nodeToUpdate);

    Node updatedNode = new Node
    {
        NodeName = "nodeName",
        StartDate = DateTime.Now.AddDays(2),
        NodeState = NodeState.Open
    };

    INodeStore stubNodeStore = new CENSORED.StubINodeStore
    {
        GetNodeString = (NodeId) =>
        {
            return nodeToUpdate;
        }
    };
    server.NodeStoreStubs = stubNodeStore;

    INodePrivilegeStore stubNodePrivilegeStore = new CENSORED.StubINodePrivilegeStore
    {
        GetPrivilegeStringString = (NodeId, subject) =>
        {
            return new NodePrivilege
            {
                Permissions = NodePermissions.Administrator
            };
        }
    };
    server.NodePrivilegeStoreStubs = stubNodePrivilegeStore;

    m_NodeManager = ThrowHelper.GetServiceOrThrow<INodeManager>(server);
    //Act
    m_NodeManager.UpdateNode(updatedNode);
    //Assert
}

[TestMethod] // Unit Test that is fully covered
[ExpectedException(typeof(Exception))]
public void ChangeStartDate() // Unit Test where the Start Date is changed when not in Edit Mode
{
    //Arrange
    Node nodeToUpdate = new Node
    {
        NodeName = "nodeName",
        StartDate = DateTime.Now.AddDays(1),
        Description = "description,
        NodeState = NodeState.Open
    };
    collectionNode.Add(nodeToUpdate);

    Node updatedNode = new Node
    {
        NodeName = "nodeName",
        StartDate = DateTime.Now.AddDays(1),
        Description = "updatedDescription"
        NodeState = NodeState.Open
    };

    INodeStore stubNodeStore = new CENSORED.StubINodeStore
    {
        GetNodeString = (NodeId) =>
        {
            return nodeToUpdate;
        }
    };
    server.NodeStoreStubs = stubNodeStore;

    INodePrivilegeStore stubNodePrivilegeStore = new CENSORED.StubINodePrivilegeStore
    {
        GetPrivilegeStringString = (NodeId, subject) =>
        {
            return new NodePrivilege
            {
                Permissions = NodePermissions.Administrator
            };
        }
    };
    server.NodePrivilegeStoreStubs = stubNodePrivilegeStore;

    m_NodeManager = ThrowHelper.GetServiceOrThrow<INodeManager>(server);
    //Act
    m_NodeManager.UpdateNode(updatedNode);
    //Assert
}

Answer 1

在进行“如果”测试时，您应该考虑所有组合可能出现的所有情况。 如果不确定if的哪一部分未正确测试，请尝试将其分开，请查看未对两个值都测试过的'if'语句。

public bool IsTimeBeforeNow(Nullable<DateTime> time)
{
    if (time.HasValue && time.Value < DateTime.Now)
        return true;
    return false;
}

[TestMethod]
public void TestIsTimeBeforeNow()
{
    //test time.HasValue with null
    Assert.AreEqual(false, this.IsTimeBeforeNow(null));
    //test time.HasValue with true
    //and test time.Value > DateTime.Now            
    Assert.AreEqual(false, this.IsTimeBeforeNow(DateTime.Now.AddDays(1)));
    //test time.HasValue with true
    //and test time.Value < DateTime.Now
    Assert.AreEqual(true, this.IsTimeBeforeNow(DateTime.Now.AddDays(-1)));
}

Answer 2

关键是测试每个逻辑路径。

如果具有“ if”语句，则必须测试if == true和if == false方案，以具有完整的代码覆盖率。

当您具有“ switch”语句时，必须测试所有可能的情况，包括默认情况。