prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Get PFS test working.
  PFS does not produce history files because it does not set HIST_N or HIST_OPTION. The test fails because it tries to move history files that aren't there.
  
  
  </issue>
  <code>
  [start of utils/python/CIME/SystemTests/pfs.py]
  1 """
  2 CIME performance test  This class inherits from SystemTestsCommon
  3 
  4 20 days performance test, no restart files written
  5 """
  6 
  7 from CIME.XML.standard_module_setup import *
  8 from CIME.SystemTests.system_tests_common import SystemTestsCommon
  9 
  10 logger = logging.getLogger(__name__)
  11 
  12 class PFS(SystemTestsCommon):
  13 
  14     def __init__(self, case):
  15         """
  16         initialize an object interface to the PFS system test
  17         """
  18         SystemTestsCommon.__init__(self, case)
  19 
  20     def run_phase(self):
  21         self._case.set_value("STOP_OPTION", "ndays")
  22         self._case.set_value("STOP_N", 20)
  23         self._case.set_value("REST_OPTION","none")
  24         self._case.set_value("CONTINUE_RUN", False)
  25         self._case.flush()
  26 
  27         logger.info("doing an 20 day initial test, no restarts written")
  28         self.run_indv()
  29
  [end of utils/python/CIME/SystemTests/pfs.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/utils/python/CIME/SystemTests/pfs.py b/utils/python/CIME/SystemTests/pfs.py
  --- a/utils/python/CIME/SystemTests/pfs.py
  +++ b/utils/python/CIME/SystemTests/pfs.py
  @@ -18,11 +18,5 @@
           SystemTestsCommon.__init__(self, case)
   
       def run_phase(self):
  -        self._case.set_value("STOP_OPTION", "ndays")
  -        self._case.set_value("STOP_N", 20)
  -        self._case.set_value("REST_OPTION","none")
  -        self._case.set_value("CONTINUE_RUN", False)
  -        self._case.flush()
  -
           logger.info("doing an 20 day initial test, no restarts written")
  -        self.run_indv()
  +        self.run_indv(suffix=None)
  
verification_info: {"golden_diff": "diff --git a/utils/python/CIME/SystemTests/pfs.py b/utils/python/CIME/SystemTests/pfs.py\n--- a/utils/python/CIME/SystemTests/pfs.py\n+++ b/utils/python/CIME/SystemTests/pfs.py\n@@ -18,11 +18,5 @@\n         SystemTestsCommon.__init__(self, case)\n \n     def run_phase(self):\n-        self._case.set_value(\"STOP_OPTION\", \"ndays\")\n-        self._case.set_value(\"STOP_N\", 20)\n-        self._case.set_value(\"REST_OPTION\",\"none\")\n-        self._case.set_value(\"CONTINUE_RUN\", False)\n-        self._case.flush()\n-\n         logger.info(\"doing an 20 day initial test, no restarts written\")\n-        self.run_indv()\n+        self.run_indv(suffix=None)\n", "issue": "Get PFS test working.\nPFS does not produce history files because it does not set HIST_N or HIST_OPTION. The test fails because it tries to move history files that aren't there.\n\n", "before_files": [{"content": "\"\"\"\nCIME performance test  This class inherits from SystemTestsCommon\n\n20 days performance test, no restart files written\n\"\"\"\n\nfrom CIME.XML.standard_module_setup import *\nfrom CIME.SystemTests.system_tests_common import SystemTestsCommon\n\nlogger = logging.getLogger(__name__)\n\nclass PFS(SystemTestsCommon):\n\n    def __init__(self, case):\n        \"\"\"\n        initialize an object interface to the PFS system test\n        \"\"\"\n        SystemTestsCommon.__init__(self, case)\n\n    def run_phase(self):\n        self._case.set_value(\"STOP_OPTION\", \"ndays\")\n        self._case.set_value(\"STOP_N\", 20)\n        self._case.set_value(\"REST_OPTION\",\"none\")\n        self._case.set_value(\"CONTINUE_RUN\", False)\n        self._case.flush()\n\n        logger.info(\"doing an 20 day initial test, no restarts written\")\n        self.run_indv()\n", "path": "utils/python/CIME/SystemTests/pfs.py"}]}