C#: Minor re-write to enable OS independant testing of dependabot proxy object creation.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependabotProxy.cs

@@ -76,9 +76,7 @@ private DependabotProxy(IDependabotProxyConfiguration config, ILogger logger, Te
             }
         }
 
-
-        internal static IDependabotProxy? GetDependabotProxy(
-            ILogger logger, IDiagnosticsWriter diagnosticsWriter, TemporaryDirectory tempWorkingDirectory)
+        internal static IDependabotProxy? Make(ILogger logger, IDiagnosticsWriter diagnosticsWriter, TemporaryDirectory tempWorkingDirectory)
         {
             // Setting HTTP(S)_PROXY and SSL_CERT_FILE have no effect on Windows or macOS,
             // but we would still end up using the Dependabot proxy to check for feed reachability.
@@ -90,8 +88,12 @@ private DependabotProxy(IDependabotProxyConfiguration config, ILogger logger, Te
                 return null;
             }
 
-            var proxyConfig = new DependabotProxyConfiguration();
+            return MakeAux(new DependabotProxyConfiguration(), logger, diagnosticsWriter, tempWorkingDirectory);
+        }
 
+        internal static IDependabotProxy? MakeAux(
+            IDependabotProxyConfiguration proxyConfig, ILogger logger, IDiagnosticsWriter diagnosticsWriter, TemporaryDirectory tempWorkingDirectory)
+        {
             if (string.IsNullOrWhiteSpace(proxyConfig.Host) || string.IsNullOrWhiteSpace(proxyConfig.Port))
             {
                 logger.LogInfo("No Dependabot proxy credentials are configured.");

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs

@@ -106,7 +106,7 @@ void exitCallback(int ret, string msg, bool silent)
                 return BuildScript.Success;
             }).Run(SystemBuildActions.Instance, startCallback, exitCallback);
 
-            dependabotProxy = DependabotProxy.GetDependabotProxy(logger, diagnosticsWriter, tempWorkingDirectory);
+            dependabotProxy = DependabotProxy.Make(logger, diagnosticsWriter, tempWorkingDirectory);
 
             try
             {