diff --git a/src/toolset/ext.rs b/src/toolset/ext.rs
index 55eb728..da80586 100644
--- a/src/toolset/ext.rs
+++ b/src/toolset/ext.rs
@@ -288,7 +288,9 @@ const COMPLUS_NS_PREFIX: &str = "complus";
 const COMPLUS_NS_URI: &str = "http://wixtoolset.org/schemas/v4/wxs/complus";
 
 const DEPENDENCY_EXT: &str = "WixToolset.Dependency.wixext";
-const DEPENDENCY_NS_PREFIX: &str = "dependency";
+/// Source of namespace prefix:
+/// https://github.com/wixtoolset/wix/blob/dd2fe20d9fe58719445411524bd730495140d02f/src/wix/test/WixToolsetTest.Converters/DependencyFixture.cs#L19
+const DEPENDENCY_NS_PREFIX: &str = "dep";
 const DEPENDENCY_NS_URI: &str = "http://wixtoolset.org/schemas/v4/wxs/dependency";
 
 const DIRECTX_EXT: &str = "WixToolset.DirectX.wixext";
@@ -296,7 +298,9 @@ const DIRECTX_NS_PREFIX: &str = "directx";
 const DIRECTX_NS_URI: &str = "http://wixtoolset.org/schemas/v4/wxs/directx";
 
 const FIREWALL_EXT: &str = "WixToolset.Firewall.wixext";
-const FIREWALL_NS_PREFIX: &str = "firewall";
+/// Source of namespace prefix:
+/// https://github.com/wixtoolset/wix/blob/dd2fe20d9fe58719445411524bd730495140d02f/src/wix/test/WixToolsetTest.Converters/FirewallExtensionFixture.cs#L19
+const FIREWALL_NS_PREFIX: &str = "fw";
 const FIREWALL_NS_URI: &str = "http://wixtoolset.org/schemas/v4/wxs/firewall";
 
 const HTTP_EXT: &str = "WixToolset.Http.wixext";
diff --git a/tests/common/pre_v4/main-2.wxs b/tests/common/pre_v4/main-2.wxs
deleted file mode 100644
index 819e5bd..0000000
--- a/tests/common/pre_v4/main-2.wxs
+++ /dev/null
@@ -1,61 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!-- Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information. -->
-
-
-
-<?include WixVer.wxi ?>
-
-<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi" xmlns:swid="http://schemas.microsoft.com/wix/TagExtension" xmlns:util="http://schemas.microsoft.com/wix/UtilExtension">
-    <Product Id="*" Name="!(loc.ShortProduct) v$(var.WixMajorMinor) Core" Language="1033" Manufacturer="!(loc.Company)"
-             Version="$(var.WixMsiProductVersion)" UpgradeCode="3618724B-2523-44F9-A908-866AA619504D">
-        <Package Compressed="yes" InstallerVersion="200" SummaryCodepage="1252" InstallScope="perMachine" />
-        <swid:Tag Regid="!(loc.Regid)" InstallDirectory="INSTALLFOLDER" />
-
-        <MajorUpgrade DowngradeErrorMessage="A later version of [ProductName] is already installed." />
-
-        <MediaTemplate CabinetTemplate="core{0}.cab" />
-
-        <Feature Id="Feature_WiX" Title="WiX Toolset" Level="1">
-            <Component Id="Licensing" Directory="INSTALLFOLDER">
-                <File Source="LICENSE.TXT" />
-            </Component>
-
-            <Component Id="ProductRegistration" Directory="INSTALLFOLDER">
-                <RegistryKey Root="HKLM" Key="SOFTWARE\Microsoft\Windows Installer XML\$(var.WixMajorMinor)">
-                    <RegistryValue Name="InstallFolder" Value="[INSTALLFOLDER]" Type="string" />
-                </RegistryKey>
-            </Component>
-
-            <Component Id="ProductFamilyRegistration" Directory="INSTALLFOLDER">
-                <RegistryKey Root="HKLM" Key="SOFTWARE\Microsoft\Windows Installer XML\$(var.WixMajor).x">
-                    <RegistryValue Name="v$(var.WixMajorMinor)" Value="[INSTALLFOLDER]" Type="string" />
-                </RegistryKey>
-            </Component>
-
-            <Component Id="ProductInformation" Directory="BinFolder">
-                <RegistryKey Root="HKLM" Key="SOFTWARE\Microsoft\Windows Installer XML\$(var.WixMajorMinor)">
-                    <RegistryValue Name="InstallRoot" Value="[BinFolder]" Type="string"/>
-                    <RegistryValue Name="ProductVersion" Value="[ProductVersion]" Type="string" />
-                </RegistryKey>
-
-                <RemoveFolder Id="CleanupShortcutFolder" Directory="ShortcutFolder" On="uninstall" />
-            </Component>
-
-            <Component Directory="BinFolder">
-                <File Source="common\wixtoolset.org.ico" />
-                <util:InternetShortcut Id="wixtoolset.org" Directory="ShortcutFolder" Name="WiX Home Page" Target="http://wixtoolset.org/" IconFile="file://[#wixtoolset.org.ico]" />
-            </Component>
-
-            <ComponentGroupRef Id="ToolsetComponents" />
-            <ComponentGroupRef Id="ExtensionComponents" />
-            <ComponentGroupRef Id="LuxComponents" />
-            <ComponentGroupRef Id="DocComponents" />
-        </Feature>
-
-        <FeatureRef Id="Feature_MSBuild" />
-        <FeatureRef Id="Feature_Intellisense2010" />
-        <FeatureRef Id="Feature_Intellisense2012" />
-        <FeatureRef Id="Feature_Intellisense2013" />
-        <FeatureRef Id="Feature_Intellisense2015" />
-    </Product>
-</Wix>
\ No newline at end of file
diff --git a/tests/common/well_known_exts/main.wxs b/tests/common/well_known_exts/main.wxs
index d3f9199..acf697c 100644
--- a/tests/common/well_known_exts/main.wxs
+++ b/tests/common/well_known_exts/main.wxs
@@ -2,9 +2,9 @@
     xmlns:ui="http://wixtoolset.org/schemas/v4/wxs/ui"
     xmlns:bal="http://wixtoolset.org/schemas/v4/wxs/bal"
     xmlns:complus="http://wixtoolset.org/schemas/v4/wxs/complus"
-    xmlns:dependency="http://wixtoolset.org/schemas/v4/wxs/dependency"
+    xmlns:dep="http://wixtoolset.org/schemas/v4/wxs/dependency"
     xmlns:directx="http://wixtoolset.org/schemas/v4/wxs/directx"
-    xmlns:firewall="http://wixtoolset.org/schemas/v4/wxs/firewall"
+    xmlns:fw="http://wixtoolset.org/schemas/v4/wxs/firewall"
     xmlns:http="http://wixtoolset.org/schemas/v4/wxs/http"
     xmlns:iis="http://wixtoolset.org/schemas/v4/wxs/iis"
     xmlns:msmq="http://wixtoolset.org/schemas/v4/wxs/msmq"