diff --git a/src/Core/WinSWCore/Util/ProcessHelper.cs b/src/Core/WinSWCore/Util/ProcessHelper.cs
index fd4fdc1..3836afa 100644
--- a/src/Core/WinSWCore/Util/ProcessHelper.cs
+++ b/src/Core/WinSWCore/Util/ProcessHelper.cs
@@ -118,7 +118,6 @@ namespace winsw.Util
             }
         }
 
-        //TODO: generalize API
         /// <summary>
         /// Starts a process and asynchronosly waits for its termination.
         /// Once the process exits, the callback will be invoked.
@@ -129,24 +128,27 @@ namespace winsw.Util
         /// <param name="envVars">Additional environment variables</param>
         /// <param name="workingDirectory">Working directory</param>
         /// <param name="priority">Priority</param>
-        /// <param name="callback">Completion callback</param>
-        public static void StartProcessAndCallbackForExit(Process processToStart, String executable, string arguments, Dictionary<string, string> envVars,
-            string workingDirectory, ProcessPriorityClass priority, ProcessCompletionCallback callback)
+        /// <param name="callback">Completion callback. If null, the completion won't be monitored</param>
+        public static void StartProcessAndCallbackForExit(Process processToStart, String executable = null, string arguments = null, Dictionary<string, string> envVars = null,
+            string workingDirectory = null, ProcessPriorityClass? priority = null, ProcessCompletionCallback callback = null)
         {
             var ps = processToStart.StartInfo;
-            ps.FileName = executable;
-            ps.Arguments = arguments;
-            ps.WorkingDirectory = workingDirectory;
+            ps.FileName = executable ?? ps.FileName;
+            ps.Arguments = arguments ?? ps.Arguments;
+            ps.WorkingDirectory = workingDirectory ?? ps.WorkingDirectory;
             ps.CreateNoWindow = false;
             ps.UseShellExecute = false;
             ps.RedirectStandardInput = true; // this creates a pipe for stdin to the new process, instead of having it inherit our stdin.
             ps.RedirectStandardOutput = true;
             ps.RedirectStandardError = true;
 
-            foreach (string key in envVars.Keys)
+            if (envVars != null)
             {
-                Environment.SetEnvironmentVariable(key, envVars[key]);
-                // ps.EnvironmentVariables[key] = envs[key]; // bugged (lower cases all variable names due to StringDictionary being used, see http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=326163)
+                foreach (string key in envVars.Keys)
+                {
+                    Environment.SetEnvironmentVariable(key, envVars[key]);
+                    // ps.EnvironmentVariables[key] = envs[key]; // bugged (lower cases all variable names due to StringDictionary being used, see http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=326163)
+                }
             }
 
             //TODO: move outside, stubbed to reproduce the issue
@@ -157,15 +159,20 @@ namespace winsw.Util
             processToStart.Start();
             Logger.Info("Started process " + processToStart.Id);
 
-            if (priority != ProcessPriorityClass.Normal)
-                processToStart.PriorityClass = priority;
+            if (priority != null && priority.Value != ProcessPriorityClass.Normal) 
+            { 
+                processToStart.PriorityClass = priority.Value;
+            }
 
             // monitor the completion of the process
-            StartThread(delegate
+            if (callback != null)
             {
-                processToStart.WaitForExit();
-                callback(processToStart);
-            });
+                StartThread(delegate
+                {
+                    processToStart.WaitForExit();
+                    callback(processToStart);
+                });
+            }
         }
 
         /// <summary>
diff --git a/src/Test/winswTests/Util/FilesystemTestHelper.cs b/src/Test/winswTests/Util/FilesystemTestHelper.cs
new file mode 100644
index 0000000..63c1fb3
--- /dev/null
+++ b/src/Test/winswTests/Util/FilesystemTestHelper.cs
@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+
+namespace winswTests.Util
+{
+    class FilesystemTestHelper
+    {
+        /// <summary>
+        /// Creates a temporary directory for testing.
+        /// </summary>
+        /// <returns>tmp Dir</returns>
+        public static string CreateTmpDirectory(String testName = null)
+        {
+            string tempDirectory = Path.Combine(Path.GetTempPath(), "winswTests_" + (testName ?? "") + Path.GetRandomFileName());
+            Directory.CreateDirectory(tempDirectory);
+            Console.Out.WriteLine("Created the temporary directory: {0}", tempDirectory);
+            return tempDirectory;
+        }
+
+        /// <summary>
+        /// Parses output of the "set" command from the file
+        /// </summary>
+        /// <param name="filePath">File path</param>
+        /// <returns>Dictionary of the strings.</returns>
+        public static Dictionary<string, string> parseSetOutput(string filePath)
+        {
+            Dictionary<string, string> res = new Dictionary<string, string>();
+            var lines = File.ReadAllLines(filePath);
+            foreach(var line in lines) {
+                line.Split("=".ToCharArray(), 2);
+            }
+            return res;
+        }
+    }
+}
diff --git a/src/Test/winswTests/Util/ProcessHelperTest.cs b/src/Test/winswTests/Util/ProcessHelperTest.cs
new file mode 100644
index 0000000..d537e26
--- /dev/null
+++ b/src/Test/winswTests/Util/ProcessHelperTest.cs
@@ -0,0 +1,48 @@
+using System;
+using System.Diagnostics;
+using NUnit.Framework;
+using winsw;
+using System.IO;
+using winsw.Util;
+
+namespace winswTests.Util
+{
+
+    [TestFixture]
+    class ProcessHelperTest
+    {
+        /// <summary>
+        /// Also reported as <a href="https://issues.jenkins-ci.org/browse/JENKINS-42744">JENKINS-42744</a>
+        /// </summary>
+        [Test]
+        public void ShouldPropagateVariablesInUppercase()
+        {
+            var tmpDir = FilesystemTestHelper.CreateTmpDirectory();
+            String envFile = Path.Combine(tmpDir, "env.properties");
+            String scriptFile = Path.Combine(tmpDir, "printenv.bat");
+            File.WriteAllText(scriptFile, "set > " + envFile);
+
+
+            Process proc = new Process();
+            var ps = proc.StartInfo;
+            ps.FileName = scriptFile;
+
+            ProcessHelper.StartProcessAndCallbackForExit(proc);
+            var exited = proc.WaitForExit(5000);
+            if (!exited)
+            {
+                Assert.Fail("Process " + proc + " didn't exit after 5 seconds");
+            }
+
+            // Check several veriables, which are expected to be in Uppercase
+            var envVars = FilesystemTestHelper.parseSetOutput(envFile);
+            Assert.That(envVars.ContainsKey("PROCESSOR_ARCHITECTURE"), "No PROCESSOR_ARCHITECTURE in the injected vars");
+            Assert.That(envVars.ContainsKey("COMPUTERNAME"), "No COMPUTERNAME in the injected vars");
+            Assert.That(envVars.ContainsKey("PATHEXT"), "No PATHEXT in the injected vars");
+            
+            // And just ensure that the parsing logic is case-sensitive
+            Assert.That(!envVars.ContainsKey("computername"), "Test error: the environment parsing logic is case-insensitive");
+
+        }
+    }
+}
diff --git a/src/Test/winswTests/winswTests.csproj b/src/Test/winswTests/winswTests.csproj
index 7292731..27f3c39 100644
--- a/src/Test/winswTests/winswTests.csproj
+++ b/src/Test/winswTests/winswTests.csproj
@@ -60,6 +60,8 @@
     <Compile Include="Extensions\RunawayProcessKillerTest.cs" />
     <Compile Include="Extensions\SharedDirectoryMapperTest.cs" />
     <Compile Include="MainTest.cs" />
+    <Compile Include="Util\FilesystemTestHelper.cs" />
+    <Compile Include="Util\ProcessHelperTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ServiceDescriptorTests.cs" />
     <Compile Include="Util\CLITestHelper.cs" />