本篇會簡單講述使用 Coverlet 為專案取得測試覆蓋率。

首先，先在測試專案中，新增 coverlet.msbuild 套件：

# Location: ~/dotnet-sln
$ cd WebProj.Tests

# Location: ~/dotnet-sln/WebProj.Tests
$ dotnet add package coverlet.msbuild
Writing /var/folders/hx/lgdjx1l93pq08s35hhwb0py40000gn/T/tmpP3owm8.tmp
info : Adding PackageReference for package 'coverlet.msbuild' into project '/Users/ironman/dotnet-sln/WebProj.Tests/WebProj.Tests.csproj'.
info : Restoring packages for /Users/ironman/dotnet-sln/WebProj.Tests/WebProj.Tests.csproj...
info :   GET https://api.nuget.org/v3-flatcontainer/coverlet.msbuild/index.json
info :   OK https://api.nuget.org/v3-flatcontainer/coverlet.msbuild/index.json 1305ms
info : Package 'coverlet.msbuild' is compatible with all the specified frameworks in project '/Users/ironman/dotnet-sln/WebProj.Tests/WebProj.Tests.csproj'.
info : PackageReference for package 'coverlet.msbuild' version '2.7.0' added to file '/Users/ironman/dotnet-sln/WebProj.Tests/WebProj.Tests.csproj'.
info : Committing restore...
info : Generating MSBuild file /Users/ironman/dotnet-sln/WebProj.Tests/obj/WebProj.Tests.csproj.nuget.g.props.
info : Generating MSBuild file /Users/ironman/dotnet-sln/WebProj.Tests/obj/WebProj.Tests.csproj.nuget.g.targets.
info : Writing assets file to disk. Path: /Users/ironman/dotnet-sln/WebProj.Tests/obj/project.assets.json
log  : Restore completed in 1.79 sec for /Users/ironman/dotnet-sln/WebProj.Tests/WebProj.Tests.csproj.

接著搭配 -p:CollectCoverage=true 參數去執行 dotnet test。

$ dotnet test -p:CollectCoverage=true
Test run for /Users/ironman/dotnet-sln/WebProj.Tests/bin/Debug/netcoreapp2.2/WebProj.Tests.dll(.NETCoreApp,Version=v2.2)
Microsoft (R) Test Execution Command Line Tool Version 16.2.0-preview-20190606-02
Copyright (c) Microsoft Corporation.  All rights reserved.

Starting test execution, please wait...

Test Run Successful.
Total tests: 1
     Passed: 1
 Total time: 1.3340 Seconds

Calculating coverage result...
  Generating report '/Users/ironman/dotnet-sln/WebProj.Tests/coverage.json'

+---------------+------+--------+--------+
| Module        | Line | Branch | Method |
+---------------+------+--------+--------+
| WebProj.Views | 0%   | 0%     | 0%     |
+---------------+------+--------+--------+
| WebProj       | 0%   | 0%     | 0%     |
+---------------+------+--------+--------+

+---------+------+--------+--------+
|         | Line | Branch | Method |
+---------+------+--------+--------+
| Total   | 0%   | 0%     | 0%     |
+---------+------+--------+--------+
| Average | 0%   | 0%     | 0%     |
+---------+------+--------+--------+

Tada！Line Coverage、Branch Coverage、Method Coverage 的數據就出現在命令列介面中啦！但是我目前這個專案沒有寫任何單元測試，所以都還是 0%。

To Do

• 講述 Line Coverage、Branch Coverage、Method Coverage 。
• 使用有測試案例的專案執行作為示範。
• 產生視覺化的報告。
• 搭配 Gitlab CI，並且產生 badge 放在 README.md 中。