Build and run FUNITFATES in test case dir.

Author: samsrabin

.gitmodules

@@ -28,7 +28,7 @@
 [submodule "fates"]
 path = src/fates
 url = https://github.com/adrifoster/fates
-fxtag = 5374f3924350a96ac0492d6c1ff93f7737bb97c1
+fxtag = f35b05f03a1f9ed976bf75af0543fc324647927f
 fxrequired = AlwaysRequired
 # Standard Fork to compare to with "git fleximod test" to ensure personal forks aren't committed
 fxDONOTUSEurl = https://github.com/NGEET/fates

cime_config/SystemTests/funitfates.py

@@ -26,15 +26,13 @@ def __init__(self, case):
         FUNIT.__init__(self, case)
 
     def run_phase(self):
-        # Change to the FATES testing directory
-        os.chdir(_FATES_TESTING_PYTHON)
-
-        # Run the testing
-        script_name = "run_unit_tests.py"
+        tool_path = os.path.join(_FATES_TESTING_PYTHON, "run_unit_tests.py")
+        build_dir = os.path.join("bld", "fates_unit_tests")
+        cmd = f"{tool_path} -b {build_dir}"
 
         stu.run_python_script(
             self._get_caseroot(),
             "ctsm_pylib",
-            os.path.join(os.curdir, script_name),
-            os.path.join(os.curdir, script_name),
+            cmd,
+            tool_path,
         )