按時在Visual Studio中覆蓋代碼

Question

我在Visual Studio 2013中編寫單元測試，但代碼覆蓋率分析遇到問題。 語言為C＃，並使用默認的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");
    }
}

我已經為每個if語句進行了單元測試。 我的第一個成功的單元測試通過了所有這些測試，並且沒有引發錯誤，然后我有三個單獨的單元測試，分別測試每個if語句並引發錯誤。 我的問題是代碼分析顯示以下語句：

if (existingNode.StartDate != updatedNode.StartDate)

因為僅進行了部分測試，我無法理解為什么。 這是因為它需要時間嗎？

在下面的代碼中也是如此，其中代碼覆蓋了引發，但是部分if語句覆蓋了所有代碼。

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."));
    }

有人要求提供單元測試的一些示例。 接下來是與第一種情況有關的兩個。 如果您在其他情況下需要它們，請告訴我。

[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

在進行“如果”測試時，您應該考慮所有組合可能出現的所有情況。 如果不確定if的哪一部分未正確測試，請嘗試將其分開，請查看未對兩個值都測試過的'if'語句。

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

關鍵是測試每個邏輯路徑。

如果具有“ if”語句，則必須測試if == true和if == false方案，以具有完整的代碼覆蓋率。

當您具有“ switch”語句時，必須測試所有可能的情況，包括默認情況。