按时 Visual Studio 的代码覆盖率

Question

我在 Visual Studio 2013 年编写单元测试，但在我的代码覆盖率分析中遇到了问题。语言是 C# 并使用默认 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 语句做了单元测试。我的第一个单元测试是成功的，它通过了所有这些并且没有抛出任何错误，然后我有三个单独的单元测试来测试每个 if 语句并抛出错误。我的问题是代码分析显示语句：

if (existingNode.StartDate != updatedNode.StartDate)

只进行了部分测试，我不明白为什么。这是因为它处理时间吗？

以下代码也是如此，其中抛出被代码覆盖，但所有 if 语句都被代码部分覆盖。

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。以下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 'if' 测试时，您应该考虑所有组合的所有可能情况。如果您不确定 if 的哪一部分未被正确测试，请尝试将它们分开，请查看哪个 'if' 语句未针对两个值进行测试。

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

关键是测试每条逻辑路径。

当你有一个 "if" 语句时，你必须同时测试 if == true 和 if == false 场景，以获得完整的代码覆盖率。

当您有一个 "switch" 语句时，您必须测试所有可能的情况，包括默认情况。

按时 Visual Studio 的代码覆盖率

Code Coverage in Visual Studio on Time

c#

datetime

unit-testing

visual-studio