Fix code coverage in trigger branch (#880)

* run only csharp test task

* comment out trigger tests

* don't start func hosts in the beginning

* start three functions in beginning

* start only csharp host

* fix build error

* start both csharp and java hosts

* start only csharp and oop hosts

* add logging for disposefunctionhosts

* start only csharp host

* revert commented out code

* add comment

Author: lucyzhang929

test/Integration/IntegrationTestFixture.cs

@@ -9,6 +9,7 @@
 using Microsoft.Azure.WebJobs.Extensions.Sql.Tests.Common;
 using Xunit;
 using static Microsoft.Azure.WebJobs.Extensions.Sql.Telemetry.Telemetry;
+using System.Linq;
 
 namespace Microsoft.Azure.WebJobs.Extensions.Sql.Tests.Integration
 {
@@ -47,7 +48,6 @@ public class IntegrationTestFixture : IDisposable
         /// </summary>
         private readonly List<string> TestFunctions = new() { "GetProductsColumnTypesSerialization", "AddProductColumnTypes", "AddProductExtraColumns", "AddProductMissingColumns", "AddProductMissingColumnsExceptionFunction", "AddProductsNoPartialUpsert", "AddProductIncorrectCasing", "AddProductDefaultPKAndDifferentColumnOrder" };
 
-
         /// <summary>
         /// Host processes for Azure Function CLI.
         /// </summary>
@@ -66,7 +66,11 @@ public IntegrationTestFixture()
         private void StartFunctionHosts()
         {
             string binPath = TestUtils.GetPathToBin();
-            foreach (SupportedLanguages lang in Enum.GetValues(typeof(SupportedLanguages)))
+            // Only start CSharp host for CSharp only tests task to ensure code coverage shows in pipeline.
+            string languages = Environment.GetEnvironmentVariable("LANGUAGES_TO_TEST");
+            SupportedLanguages[] supportedLanguages = languages == null ? (SupportedLanguages[])Enum.GetValues(typeof(SupportedLanguages))
+                : languages.Split(',').Select(l => (SupportedLanguages)Enum.Parse(typeof(SupportedLanguages), l)).ToArray();
+            foreach (SupportedLanguages lang in supportedLanguages)
             {
                 if (lang == SupportedLanguages.CSharp)
                 {