From ad4df07bf2ea70334ada357d1240099e61b1d170 Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Tue, 24 Jul 2018 08:22:31 -0700
Subject: [PATCH] Work around cmd command length limit in xunit Exec task
 (#19095)

On Windows, the Exec task passes the command to cmd, so long commands
run into the command length limit (see
https://github.com/Microsoft/msbuild/issues/2530). This workaround
shortens the xunit command line by replacing the path to the test
binary directory with an environment variable.
---
 tests/src/dir.props |  2 +-
 tests/tests.targets | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/tests/src/dir.props b/tests/src/dir.props
index f3f229d..2730073 100644
--- a/tests/src/dir.props
+++ b/tests/src/dir.props
@@ -33,7 +33,7 @@
 
 <!-- Setup the default output and intermediate paths -->
   <PropertyGroup>
-    <BaseOutputPath>$(ProjectDir)\..\bin\tests</BaseOutputPath>
+    <BaseOutputPath>$(ProjectDir)..\bin\tests</BaseOutputPath>
     <BaseOutputPath Condition="'$(__TestRootDir)' != ''">$(__TestRootDir)</BaseOutputPath>
     <BaseOutputPathWithConfig>$(BaseOutputPath)\$(OSPlatformConfig)\</BaseOutputPathWithConfig>
     <BinDir>$(BaseOutputPathWithConfig)</BinDir>
diff --git a/tests/tests.targets b/tests/tests.targets
index 9a16cb0..e1e6f58 100644
--- a/tests/tests.targets
+++ b/tests/tests.targets
@@ -50,9 +50,24 @@
 
       <CorerunExecutable Condition="'$(RunningOnUnix)' == 'true'">$(CORE_ROOT)\corerun</CorerunExecutable>
       <CorerunExecutable Condition="'$(RunningOnUnix)' != 'true'">$(CORE_ROOT)\corerun.exe</CorerunExecutable>
+    </PropertyGroup>
+
+    <!-- Work around cmd command length limit by using relative paths
+         from working directory instead of full paths (see
+         https://github.com/Microsoft/msbuild/issues/2530) -->
+    <ItemGroup Condition="'$(RunningOnUnix)' != 'true'">
+      <_TestAssembliesRelative Include="@(TestAssemblies -> Replace('$(BaseOutputPathWithConfig)', '.\'))" />
+      <TestAssemblies Remove="@(TestAssemblies)" />
+      <TestAssemblies Include="@(_TestAssembliesRelative)" />
+    </ItemGroup>
+
+    <PropertyGroup>
       <XunitCommandLine>$(CorerunExecutable) $(XunitConsoleRunner) @(TestAssemblies->'%(Identity)', ' ') $(XunitArgs)</XunitCommandLine>
     </PropertyGroup>
-    <Exec Command="$(XunitCommandLine)" />
+
+    <Error Condition="$(XunitCommandLine.Length) > 8191" Text="Xunit command line is too long." />
+    <Exec Command="$(XunitCommandLine)"
+          WorkingDirectory="$(BaseOutputPathWithConfig)"/>
 
   </Target>
 
-- 
2.7.4