C#: Add integration test.

Author: michaelnebel

csharp/ql/integration-tests/posix-only/dotnet_test/dotnet_test.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
     <Nullable>enable</Nullable>
-
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
@@ -14,4 +13,9 @@
     <PackageReference Include="coverlet.collector" Version="3.2.0" />
   </ItemGroup>
 
+  <Target Name="DeleteBinObjFolders" BeforeTargets="Clean">
+    <RemoveDir Directories=".\bin" />
+    <RemoveDir Directories=".\obj" />
+    <RemoveDir Directories=".\myout" />
+  </Target>
 </Project>

csharp/ql/integration-tests/posix-only/dotnet_test/test.py

@@ -8,3 +8,8 @@
 # Explicitly build and then run tests.
 run_codeql_database_create(['dotnet clean', 'rm -rf test-db', 'dotnet build -o myout', 'dotnet test myout/dotnet_test.dll'], test_db="test2-db", lang="csharp")
 check_diagnostics(test_db="test2-db")
+
+thisDir = os.path.abspath(os.getcwd())
+# Explicit build and then run tests using the absolute path.
+run_codeql_database_create(['dotnet clean', 'rm -rf test2-db', 'dotnet build -o myout', f'dotnet test {thisDir}/myout/dotnet_test.dll'], test_db="test3-db", lang="csharp")
+check_diagnostics(test_db="test3-db")