change working directory when running C compiler to make it work with relative path names

runtests.py

@@ -121,6 +121,9 @@ class CythonCompileTestCase(unittest.TestCase):
                        full_module_name=module)
 
     def run_distutils(self, module, workdir, incdir):
+        cwd = os.getcwd()
+        os.chdir(workdir)
+        try:
             build_extension = build_ext(distutils_distro)
             build_extension.include_dirs = INCLUDE_DIRS[:]
             if incdir:
@@ -129,13 +132,15 @@ class CythonCompileTestCase(unittest.TestCase):
 
             extension = Extension(
                 module,
-            sources = [os.path.join(workdir, module + '.c')],
+                sources = [module + '.c'],
                 extra_compile_args = CFLAGS,
                 )
             build_extension.extensions = [extension]
             build_extension.build_temp = workdir
             build_extension.build_lib  = workdir
             build_extension.run()
+        finally:
+            os.chdir(cwd)
 
     def compile(self, directory, module, workdir, incdir, expect_errors):
         expected_errors = errors = ()
@@ -165,9 +170,6 @@ class CythonCompileTestCase(unittest.TestCase):
             self.run_distutils(module, workdir, incdir)
 
 class CythonRunTestCase(CythonCompileTestCase):
-    def shortDescription(self):
-        return "compiling and running " + self.module
-
     def runTest(self):
         self.run()