diff --git a/tests/unit/core.tests.ps1 b/tests/unit/core.tests.ps1
index ac81676..89d8cfa 100644
--- a/tests/unit/core.tests.ps1
+++ b/tests/unit/core.tests.ps1
@@ -6,23 +6,36 @@ Describe 'CallRestUri' {
     InModuleScope Qlik-Cli {
         Describe 'when uploading or downloading files' {
             BeforeAll {
-                Mock Invoke-WebRequest -Verifiable { return $UseBasicParsing }
+                Mock Invoke-WebRequest -Verifiable {
+                    $script:webSessionContainer = @{ Headers = $Headers }
+                    return @{
+                        UseBasicParsing = $UseBasicParsing
+                        TransferEncodingHeader = $Headers.ContainsKey('Transfer-Encoding')
+                    }
+                }
                 Mock Invoke-RestMethod { throw 'Invoke-RestMethod should not be used for file transfers' }
                 $script:prefix = 'https://localhost'
                 $script:api_params = @{ }
                 $script:rawOutput = $true
             }
 
+            BeforeEach {
+                $script:webSessionContainer = $null
+            }
+
             It 'should use Invoke-WebRequest' {
                 CallRestUri GET /qrs/download/scriptlog @{ OutFile = 'TestDrive:\script.log' }
 
                 Assert-VerifiableMock
             }
 
-            It 'should use basic parsing' {
+            It 'should use basic parsing and transfer-encoding header for uploads' {
                 $result = CallRestUri GET /qrs/app/upload @{ InFile = 'TestDrive:\app.qvf' }
 
-                $result | Should -BeTrue
+                $result.UseBasicParsing | Should -BeTrue
+                $result.TransferEncodingHeader | Should -BeTrue
+                # Header should be present in request and removed from session after
+                $script:webSessionContainer.Headers.Keys | Should -Not -Contain 'Transfer-Encoding'
 
                 Assert-VerifiableMock
             }