Switch to @coverlet-coverage for test coverage

This is due to OpenCover generating inconsistent reports: some LOCs were
shown not covered by tests, despite actually being covered. For example,
some edge cases in Models were covered by 0846e27 — but the coverage did
not go up for some unknown reason(s).

The global CLI tool, `coverlet.console`, has been used for this project.

There are now separate scripts for generating reports and uploading test
coverage — for Windows and Unix-like platforms.

.gitignore

@@ -345,3 +345,4 @@ src/global.json
 tests/global.json
 .env
 report
+coverage*xml

appveyor.yml

@@ -9,7 +9,8 @@ init:
 
 before_build:
 - dotnet --info
-- choco install xunit opencover.portable codecov
+- choco install codecov
+- dotnet tool install --global coverlet.console
 - dotnet restore
 
 build:
@@ -27,8 +28,8 @@ artifacts:
   - path: dist
 
 test_script:
-- OpenCover.Console.exe -register:user -target:"C:/Program Files/dotnet/dotnet.exe" -targetargs:test -filter:"+[KonSchool*]* -[KonSchool.Tests*]*" -excludebyfile:".\src\Services\SchoolService.cs" -output:".\KonSchool_coverage.xml" -oldstyle
-- codecov -f "KonSchool_coverage.xml" -t %CODECOV_TOKEN%
+- coverlet tests/bin/Debug/netcoreapp3.1/KonSchool.Tests.dll --target "dotnet" --targetargs "test tests/KonSchool.Tests.csproj --no-build" --format opencover
+- codecov -f "coverage.opencover.xml" -t %CODECOV_TOKEN%
 
 deploy:
   provider: WebDeploy

scripts/generate-test-coverage-report.ps1

@@ -1,21 +1,29 @@
 # The following tools must be installed for this to work:
-# `xunit`, `opencover.portable`, `codecov`, and `dotnet-reportgenerator-globaltool`
+# `coverlet` and `dotnet-reportgenerator-globaltool`
 
 # These can be installed via the following commands:
-# choco install xunit opencover.portable codecov
+# dotnet tool install --global coverlet.console
 # dotnet tool install --global dotnet-reportgenerator-globaltool
 
-OpenCover.Console.exe `
-    -register:user `
-    -target:"C:\Program Files\dotnet\dotnet.exe" `
-    -targetargs:test `
-    -filter:"+[KonSchool*]* -[KonSchool.Tests*]*" `
-    -excludebyfile:"SchoolService.cs" `
-    -output:".\report\KonSchool_coverage.xml" `
-    -oldstyle
-
-reportgenerator -reports:.\report\KonSchool_coverage.xml -reporttypes:Html -targetdir:.\report
-dotnet serve -d .\report -p 5050
+# First, build the projects
+dotnet build
+
+# Now, let's run the tests and collect the coverage
+coverlet tests/bin/Debug/netcoreapp3.1/KonSchool.Tests.dll `
+    --target "dotnet" `
+    --targetargs "test tests/KonSchool.Tests.csproj --no-build" `
+    --format opencover
+
+reportgenerator -reports:./coverage.opencover.xml -reporttypes:Html -targetdir:./report
+
+# After generating the report, you can either open `report/index.html` file
+# directly in your browser, or you can use `dotnet-serve` tool to serve
+# the `report` directory.
+
+# You can install the tool by  the following command:
+# dotnet tool install --global dotnet-serve
+
+dotnet serve -d ./report -p 5050
 
 # The following command opens the report in the default web browser:
 # Invoke-Expression “cmd.exe /C start http://localhost:5050"

scripts/generate-test-coverage-report.sh

@@ -0,0 +1,31 @@
+# The following tools must be installed for this to work:
+# `coverlet` and `dotnet-reportgenerator-globaltool`
+
+# These can be installed via the following commands:
+# dotnet tool install --global coverlet.console
+# dotnet tool install --global dotnet-reportgenerator-globaltool
+
+# First, build the projects
+dotnet build
+
+# Now, let's run the tests and collect the coverage
+coverlet tests/bin/Debug/netcoreapp3.1/KonSchool.Tests.dll \
+    --target "dotnet" \
+    --targetargs "test tests/KonSchool.Tests.csproj --no-build" \
+    --format opencover
+
+reportgenerator -reports:./coverage.opencover.xml -reporttypes:Html -targetdir:./report
+
+# After generating the report, you can either open `report/index.html` file
+# directly in your browser, or you can use `dotnet-serve` tool to serve
+# the `report` directory.
+
+# You can install the tool by  the following command:
+# dotnet tool install --global dotnet-serve
+
+dotnet serve -d ./report -p 5050
+
+# The following command opens the report in the default web browser:
+# Invoke-Expression “cmd.exe /C start http://localhost:5050"
+
+# Or, just ctrl-click on the link above 😁

scripts/upload-test-coverage-report.ps1

@@ -0,0 +1,4 @@
+# This requires Codecov CLI tool. Install it by the following command:
+# choco install codecov
+
+codecov -f "coverage.opencover.xml" -t "token"

scripts/upload-test-coverage-report.sh

@@ -0,0 +1,2 @@
+export CODECOV_TOKEN="token"
+bash <(curl -s https://codecov.io/bash)