fix run_tests scripts

tools/run_tests/run_csharp.bat

@@ -5,12 +5,15 @@ setlocal
 @rem enter src/csharp directory
 cd /d %~dp0\..\..\src\csharp
 
+rem nunit3-console fails if nunit.framework.dll is not found.
+copy packages\NUnit.3.2.0\lib\net45\nunit.framework.dll packages\NUnit.ConsoleRunner.3.2.0\tools\nunit.framework.dll
+
 if not "%CONFIG%" == "gcov" (
-  packages\NUnit.Runners.2.6.4\tools\nunit-console-x86.exe %* || goto :error
+  packages\NUnit.ConsoleRunner.3.2.0\tools\nunit3-console.exe %* || goto :error
 ) else (
   @rem Run all tests with code coverage
 
-  packages\OpenCover.4.6.519\tools\OpenCover.Console.exe -target:"packages\NUnit.Runners.2.6.4\tools\nunit-console-x86.exe" -targetdir:"." -targetargs:"%*" -filter:"+[Grpc.Core]*"  -register:user -output:coverage_results.xml || goto :error
+  packages\OpenCover.4.6.519\tools\OpenCover.Console.exe -target:"packages\NUnit.ConsoleRunner.3.2.0\tools\nunit3-console.exe" -targetdir:"." -targetargs:"%*" -filter:"+[Grpc.Core]*"  -register:user -output:coverage_results.xml || goto :error
 
   packages\ReportGenerator.2.4.4.0\tools\ReportGenerator.exe -reports:"coverage_results.xml" -targetdir:"..\..\reports\csharp_coverage" -reporttypes:"Html;TextSummary" || goto :error
 

tools/run_tests/run_csharp.sh

@@ -31,7 +31,10 @@
 set -ex
 
 CONFIG=${CONFIG:-opt}
-NUNIT_CONSOLE="mono packages/NUnit.Runners.2.6.4/tools/nunit-console.exe"
+NUNIT_CONSOLE="mono packages/NUnit.ConsoleRunner.3.2.0/tools/nunit3-console.exe"
+
+# nunit3-console fails if nunit.framework.dll is not found.
+cp -u src/csharp/packages/NUnit.3.2.0/lib/net45/nunit.framework.dll src/csharp/packages/NUnit.ConsoleRunner.3.2.0/tools/
 
 # change to gRPC repo root
 cd $(dirname $0)/../..

tools/run_tests/run_tests.py

@@ -494,11 +494,16 @@ class CSharpLanguage(object):
     assembly_files = ['%s/bin/%s/%s.dll' % (a, msbuild_config, a)
                       for a in assemblies]
 
-    extra_args = ['-labels'] + assembly_files
+    # TODO(jtattermusch): use --x86 when needed
+
+    extra_args = ['--labels=All',
+                  '--noresult',
+                  '--workers=1',
+                  '--inprocess'] + assembly_files
 
     if self.platform == 'windows':
       script_name = 'tools\\run_tests\\run_csharp.bat'
-      extra_args += ['-domain=None']
+      extra_args += ['--domain=None']
     else:
       script_name = 'tools/run_tests/run_csharp.sh'
 
@@ -512,11 +517,7 @@ class CSharpLanguage(object):
     else:
       specs = []
       for test in tests:
-        cmdline = [script_name, '-run=%s' % test] + extra_args
-        if self.platform == 'windows':
-          # use different output directory for each test to prevent
-          # TestResult.xml clash between parallel test runs.
-          cmdline += ['-work=test-result/%s' % uuid.uuid4()]
+        cmdline = [script_name, '--test=%s' % test] + extra_args
         specs.append(self.config.job_spec(cmdline, None,
                                           shortname='csharp.%s' % test,
                                           environ=_FORCE_ENVIRON_FOR_WRAPPERS))