diff --git a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Common/DeploymentParameters.cs b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Common/DeploymentParameters.cs
index 27640090c8..d61d266085 100644
--- a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Common/DeploymentParameters.cs
+++ b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Common/DeploymentParameters.cs
@@ -44,7 +44,7 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
             ApplicationName = new DirectoryInfo(ApplicationPath).Name;
             ServerType = serverType;
             RuntimeFlavor = runtimeFlavor;
-            EnvironmentVariables.Add(new KeyValuePair<string, string>("ASPNETCORE_DETAILEDERRORS", "true"));
+            EnvironmentVariables["ASPNETCORE_DETAILEDERRORS"] = "true";
         }
 
         public ServerType ServerType { get; }
@@ -103,12 +103,12 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
         /// Environment variables to be set before starting the host.
         /// Not applicable for IIS Scenarios.
         /// </summary>
-        public List<KeyValuePair<string, string>> EnvironmentVariables { get; } = new List<KeyValuePair<string, string>>();
+        public IDictionary<string, string> EnvironmentVariables { get; } = new Dictionary<string, string>();
 
         /// <summary>
         /// Environment variables used when invoking dotnet publish.
         /// </summary>
-        public List<KeyValuePair<string, string>> PublishEnvironmentVariables { get; } = new List<KeyValuePair<string, string>>();
+        public IDictionary<string, string> PublishEnvironmentVariables { get; } = new Dictionary<string, string>();
 
         /// <summary>
         /// For any application level cleanup to be invoked after performing host cleanup.
@@ -126,4 +126,4 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
                     PublishApplicationBeforeDeployment);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/ApplicationDeployer.cs b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/ApplicationDeployer.cs
index 6ec210ba07..d2370c9e27 100644
--- a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/ApplicationDeployer.cs
+++ b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/ApplicationDeployer.cs
@@ -139,7 +139,7 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
             }
         }
 
-        protected void AddEnvironmentVariablesToProcess(ProcessStartInfo startInfo, List<KeyValuePair<string, string>> environmentVariables)
+        protected void AddEnvironmentVariablesToProcess(ProcessStartInfo startInfo, IDictionary<string, string> environmentVariables)
         {
             var environment = startInfo.Environment;
             SetEnvironmentVariable(environment, "ASPNETCORE_ENVIRONMENT", DeploymentParameters.EnvironmentName);
diff --git a/test/Microsoft.AspNetCore.Hosting.FunctionalTests/ShutdownTests.cs b/test/Microsoft.AspNetCore.Hosting.FunctionalTests/ShutdownTests.cs
index d9a17b70e7..341366bd8a 100644
--- a/test/Microsoft.AspNetCore.Hosting.FunctionalTests/ShutdownTests.cs
+++ b/test/Microsoft.AspNetCore.Hosting.FunctionalTests/ShutdownTests.cs
@@ -44,7 +44,7 @@ namespace Microsoft.AspNetCore.Hosting.FunctionalTests
                     PublishApplicationBeforeDeployment = true
                 };
 
-                deploymentParameters.EnvironmentVariables.Add(new KeyValuePair<string, string>("ASPNETCORE_STARTMECHANIC", "Run"));
+                deploymentParameters.EnvironmentVariables["ASPNETCORE_STARTMECHANIC"] = "Run";
 
                 using (var deployer = new SelfHostDeployer(deploymentParameters, loggerFactory))
                 {
@@ -92,7 +92,7 @@ namespace Microsoft.AspNetCore.Hosting.FunctionalTests
                     PublishApplicationBeforeDeployment = true
                 };
 
-                deploymentParameters.EnvironmentVariables.Add(new KeyValuePair<string, string>("ASPNETCORE_STARTMECHANIC", "WaitForShutdown"));
+                deploymentParameters.EnvironmentVariables["ASPNETCORE_STARTMECHANIC"] = "WaitForShutdown";
 
                 using (var deployer = new SelfHostDeployer(deploymentParameters, loggerFactory))
                 {