diff --git a/eng/testing/tests.browser.targets b/eng/testing/tests.browser.targets
index 4264bde6d01999..911719ab33faa6 100644
--- a/eng/testing/tests.browser.targets
+++ b/eng/testing/tests.browser.targets
@@ -71,22 +71,16 @@
     Any settings in the project file could be replaced on Helix.
     See also eng\testing\WasmRunnerTemplate.sh
     -->
-  <ItemGroup Condition="'$(OS)' != 'Windows_NT'">
-    <SetScriptCommands Condition="'$(Scenario)' != '' and '$(ContinuousIntegrationBuild)' != 'true'" Include="export SCENARIO=$(Scenario)" />
-    <SetScriptCommands Condition="'$(JSEngine)' != ''" Include="export JS_ENGINE=--engine=$(JSEngine)" />
-    <SetScriptCommands Condition="'$(JSEngineArgs)' != ''" Include="export JS_ENGINE_ARGS=$(JSEngineArgs)" />
-    <SetScriptCommands Condition="'$(_WasmJSEnginePathForTests)' != ''" Include="export V8_PATH_FOR_TESTS=${V8_PATH_FOR_TESTS:=$(_WasmJSEnginePathForTests)}" />
-    <SetScriptCommands Condition="'$(_WasmMainJSFileName)' != ''" Include="export MAIN_JS=--js-file=$(_WasmMainJSFileName)" />
+  <ItemGroup>
+    <SetScriptCommands Condition="'$(Scenario)' != '' and '$(ContinuousIntegrationBuild)' != 'true'" Include="$(EnvVarCommand) &quot;SCENARIO=$(Scenario)&quot;" />
+    <SetScriptCommands Condition="'$(JSEngine)' != ''" Include="$(EnvVarCommand) &quot;JS_ENGINE=--engine^=$(JSEngine)&quot;" />
+    <SetScriptCommands Condition="'$(JSEngineArgs)' != ''" Include="$(EnvVarCommand) &quot;JS_ENGINE_ARGS=$(JSEngineArgs)&quot;" />
+    <SetScriptCommands Condition="'$(_WasmMainJSFileName)' != ''" Include="$(EnvVarCommand) &quot;MAIN_JS=--js-file^=$(_WasmMainJSFileName)&quot;" />
     <!-- Workaround for https://github.com/dotnet/runtime/issues/74328 -->
-    <SetScriptCommands Condition="'$(BuildAOTTestsOnHelix)' == 'true'" Include="export DOTNET_CLI_DO_NOT_USE_MSBUILD_SERVER=1" />
+    <SetScriptCommands Condition="'$(BuildAOTTestsOnHelix)' == 'true'" Include="$(EnvVarCommand) DOTNET_CLI_DO_NOT_USE_MSBUILD_SERVER=1" />
   </ItemGroup>
-  <ItemGroup Condition="'$(OS)' == 'Windows_NT'">
-    <SetScriptCommands Condition="'$(Scenario)' != '' and '$(ContinuousIntegrationBuild)' != 'true'" Include="set &quot;SCENARIO=$(Scenario)&quot;" />
-    <SetScriptCommands Condition="'$(JSEngine)' != ''" Include="set &quot;JS_ENGINE=--engine^=$(JSEngine)&quot;" />
-    <SetScriptCommands Condition="'$(JSEngineArgs)' != ''" Include="set &quot;JS_ENGINE_ARGS=$(JSEngineArgs)&quot;" />
-    <SetScriptCommands Condition="'$(_WasmMainJSFileName)' != ''" Include="set &quot;MAIN_JS=--js-file^=$(_WasmMainJSFileName)&quot;" />
-    <!-- Workaround for https://github.com/dotnet/runtime/issues/74328 -->
-    <SetScriptCommands Condition="'$(BuildAOTTestsOnHelix)' == 'true'" Include="set DOTNET_CLI_DO_NOT_USE_MSBUILD_SERVER=1" />
+  <ItemGroup Condition="'$(OS)' != 'Windows_NT'">
+    <SetScriptCommands Condition="'$(_WasmJSEnginePathForTests)' != ''" Include="$(EnvVarCommand) V8_PATH_FOR_TESTS=${V8_PATH_FOR_TESTS:=$(_WasmJSEnginePathForTests)}" />
   </ItemGroup>
 
   <PropertyGroup>
@@ -251,15 +245,10 @@
                       Text="Only supported scenarios are WasmTestOnV8, WasmTestOnChrome, WasmTestOnFirefox and BuildWasmApps at the moment. It was $(Scenario)." />
 
     <!-- Restore NPM packages -->
-    <ItemGroup Condition="'$(OS)' != 'Windows_NT'">
-      <SetScriptCommands Condition="'$(InstallChromeForTests)' == 'true' and '$(ChromeDriverBinaryPath)' != ''" Include="export PREPEND_PATH=$([System.IO.Path]::GetDirectoryName($(ChromeDriverBinaryPath)))" />
-      <SetScriptCommands Condition="'$(InstallFirefoxForTests)' == 'true' and '$(GeckoDriverBinaryPath)' != ''" Include="export PREPEND_PATH=$([System.IO.Path]::GetDirectoryName($(GeckoDriverBinaryPath)))" />
-      <SetScriptCommands Condition="'$(IsBrowserWasmProject)' == 'true'" Include="export RuntimeIdentifier=browser-wasm" />
-    </ItemGroup>
-    <ItemGroup Condition="'$(OS)' == 'Windows_NT'">
-      <SetScriptCommands Condition="'$(InstallChromeForTests)' == 'true' and '$(ChromeDriverBinaryPath)' != ''" Include="set PREPEND_PATH=$([System.IO.Path]::GetDirectoryName($(ChromeDriverBinaryPath)))" />
-      <SetScriptCommands Condition="'$(InstallFirefoxForTests)' == 'true' and '$(GeckoDriverBinaryPath)' != ''" Include="set PREPEND_PATH=$([System.IO.Path]::GetDirectoryName($(GeckoDriverBinaryPath)))" />
-      <SetScriptCommands Condition="'$(IsBrowserWasmProject)' == 'true'" Include="set RuntimeIdentifier=browser-wasm" />
+    <ItemGroup>
+      <SetScriptCommands Condition="'$(InstallChromeForTests)' == 'true' and '$(ChromeDriverBinaryPath)' != ''" Include="$(EnvVarCommand) PREPEND_PATH=$([System.IO.Path]::GetDirectoryName($(ChromeDriverBinaryPath)))" />
+      <SetScriptCommands Condition="'$(InstallFirefoxForTests)' == 'true' and '$(GeckoDriverBinaryPath)' != ''" Include="$(EnvVarCommand) PREPEND_PATH=$([System.IO.Path]::GetDirectoryName($(GeckoDriverBinaryPath)))" />
+      <SetScriptCommands Condition="'$(IsBrowserWasmProject)' == 'true'" Include="$(EnvVarCommand) RuntimeIdentifier=browser-wasm" />
     </ItemGroup>
   </Target>
 </Project>
diff --git a/eng/testing/tests.props b/eng/testing/tests.props
index ad0f25da5fa054..5ff71ec66cc51f 100644
--- a/eng/testing/tests.props
+++ b/eng/testing/tests.props
@@ -9,6 +9,10 @@
     <ILLinkDescriptorsPath>$(MSBuildThisFileDirectory)ILLinkDescriptors\</ILLinkDescriptorsPath>
     <TestSingleFile Condition="'$(TestNativeAot)' == 'true'">true</TestSingleFile>
     <TestSingleFile Condition="'$(TestReadyToRun)' == 'true'">true</TestSingleFile>
+    <EnvVarCommand Condition="'$(OS)' == 'Windows_NT' or '$(TargetsWindows)' == 'true' or '$(TargetPlatformIdentifier)' == 'windows'">set</EnvVarCommand>
+    <EnvVarCommand Condition="'$(OS)' != 'Windows_NT' and '$(TargetsWindows)' != 'true' and '$(TargetPlatformIdentifier)' != 'windows'">export</EnvVarCommand>
+    <DirSeparator Condition="'$(OS)' == 'Windows_NT'">\\</DirSeparator>
+    <DirSeparator Condition="'$(OS)' != 'Windows_NT'">/</DirSeparator>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetsMobile)' == 'true'">
@@ -27,8 +31,7 @@
 
   <!-- Provide runtime options to Mono (interpreter, aot, debugging, etc) -->
   <ItemGroup Condition="'$(MonoEnvOptions)' != '' and '$(TargetsMobile)' != 'true'">
-    <RunScriptCommands Condition="'$(TargetsWindows)' == 'true' or '$(TargetPlatformIdentifier)' == 'windows'" Include="set MONO_ENV_OPTIONS='$(MonoEnvOptions)'" />
-    <RunScriptCommands Condition="'$(TargetsWindows)' != 'true' and '$(TargetPlatformIdentifier)' != 'windows'" Include="export MONO_ENV_OPTIONS='$(MonoEnvOptions)'" />
+    <RunScriptCommands Include="$(EnvVarCommand) MONO_ENV_OPTIONS='$(MonoEnvOptions)'" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TestRunRequiresLiveRefPack)' == 'true'">
diff --git a/eng/testing/tests.targets b/eng/testing/tests.targets
index f05b4aa2a67c7b..f7fb50dced1c5f 100644
--- a/eng/testing/tests.targets
+++ b/eng/testing/tests.targets
@@ -71,8 +71,7 @@
   <ItemGroup Condition="'$(IsXUnitLogCheckerSupported)' == 'true' and
                         '$(TargetFrameworkIdentifier)' == '.NETCoreApp' and
                          $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '$(NETCoreAppCurrentVersion)'))">
-    <SetScriptCommands Condition="'$(TargetOS)' == 'windows'" Include="set __IsXUnitLogCheckerSupported=1" />
-    <SetScriptCommands Condition="'$(TargetOS)' != 'windows'" Include="export __IsXUnitLogCheckerSupported=1" />
+    <SetScriptCommands Include="$(EnvVarCommand) __IsXUnitLogCheckerSupported=1" />
   </ItemGroup>
 
   <!-- Archive test binaries. -->
diff --git a/eng/testing/tests.wasi.targets b/eng/testing/tests.wasi.targets
index 066c4391ad4503..52f72440d76d72 100644
--- a/eng/testing/tests.wasi.targets
+++ b/eng/testing/tests.wasi.targets
@@ -151,13 +151,9 @@
                       '$(Scenario)' != 'BuildWasmApps'"
                       Text="Only supported scenarios are WasmTestOnWasmtime and BuildWasmApps at the moment. It was $(Scenario)." />
 
-    <ItemGroup Condition="'$(OS)' != 'Windows_NT'">
-      <SetScriptCommands Condition="'$(InstallWasmtimeForTests)' == 'true' and Exists($(WasmtimeDir))" Include="export PREPEND_PATH=$(WasmtimeDir)" />
-      <SetScriptCommands Condition="'$(IsWasiProject)' == 'true'" Include="export RuntimeIdentifier=wasi-wasm" />
-    </ItemGroup>
-    <ItemGroup Condition="'$(OS)' == 'Windows_NT'">
-      <SetScriptCommands Condition="'$(InstallWasmtimeForTests)' == 'true' and Exists($(WasmtimeDir))" Include="set PREPEND_PATH=$(WasmtimeDir)" />
-      <SetScriptCommands Condition="'$(IsWasiProject)' == 'true'" Include="set RuntimeIdentifier=wasi-wasm" />
+    <ItemGroup >
+      <SetScriptCommands Condition="'$(InstallWasmtimeForTests)' == 'true' and Exists($(WasmtimeDir))" Include="$(EnvVarCommand) PREPEND_PATH=$(WasmtimeDir)" />
+      <SetScriptCommands Condition="'$(IsWasiProject)' == 'true'" Include="$(EnvVarCommand) RuntimeIdentifier=wasi-wasm" />
     </ItemGroup>
   </Target>
 </Project>
diff --git a/eng/testing/xunit/xunit.console.targets b/eng/testing/xunit/xunit.console.targets
index b682117b75a9ec..cb79571f2f1d5c 100644
--- a/eng/testing/xunit/xunit.console.targets
+++ b/eng/testing/xunit/xunit.console.targets
@@ -13,8 +13,7 @@
 
   <ItemGroup>
     <!-- Configures xunit to not print out passing tests with output when diagnostic messages are enabled. -->
-    <SetScriptCommands Condition="'$(TargetOS)' == 'windows'" Include="set XUNIT_HIDE_PASSING_OUTPUT_DIAGNOSTICS=1" />
-    <SetScriptCommands Condition="'$(TargetOS)' != 'windows'" Include="export XUNIT_HIDE_PASSING_OUTPUT_DIAGNOSTICS=1" />
+    <SetScriptCommands Include="$(EnvVarCommand) XUNIT_HIDE_PASSING_OUTPUT_DIAGNOSTICS=1" />
   </ItemGroup>
 
   <PropertyGroup Condition="'$(BundleXunitRunner)' == 'true'">