diff --git a/tests/junit_common.py b/tests/junit_common.py
index 255f8218e2..94a888440f 100644
--- a/tests/junit_common.py
+++ b/tests/junit_common.py
@@ -13,7 +13,7 @@
 from itertools import product
 import sys
 import time
-from typing import Optional, Tuple, List
+from typing import Optional, Tuple, List, Callable
 
 sys.path.insert(0, str(Path(__file__).parent / "junit-xml"))
 from junit_xml import TestCase, TestSuite, to_xml_report_string  # nopep8
@@ -106,6 +106,15 @@ def cgns_tol(self):
     def cgns_tol(self, val):
         self._cgns_tol = val
 
+    @property
+    def diff_csv_kwargs(self):
+        """Keyword arguments to be passed to diff_csv()"""
+        return getattr(self, '_diff_csv_kwargs', {})
+
+    @diff_csv_kwargs.setter
+    def diff_csv_kwargs(self, val):
+        self._diff_csv_kwargs = val
+
     def post_test_hook(self, test: str, spec: TestSpec) -> None:
         """Function callback ran after each test case
 
@@ -262,7 +271,8 @@ def get_test_args(source_file: Path) -> List[TestSpec]:
             if line.startswith(f'{comment_str}TESTARGS')] or [TestSpec('', args=['{ceed_resource}'])]
 
 
-def diff_csv(test_csv: Path, true_csv: Path, zero_tol: float = 3e-10, rel_tol: float = 1e-2) -> str:
+def diff_csv(test_csv: Path, true_csv: Path, zero_tol: float = 3e-10, rel_tol: float = 1e-2,
+             comment_str: str = '#', comment_func: Optional[Callable[[str, str], Optional[str]]] = None) -> str:
     """Compare CSV results against an expected CSV file with tolerances
 
     Args:
@@ -270,6 +280,8 @@ def diff_csv(test_csv: Path, true_csv: Path, zero_tol: float = 3e-10, rel_tol: f
         true_csv (Path): Path to expected CSV results
         zero_tol (float, optional): Tolerance below which values are considered to be zero. Defaults to 3e-10.
         rel_tol (float, optional): Relative tolerance for comparing non-zero values. Defaults to 1e-2.
+        comment_str (str, optional): String to denoting commented line
+        comment_func (Callable, optional): Function to determine if test and true line are different
 
     Returns:
         str: Diff output between result and expected CSVs
@@ -281,6 +293,27 @@ def diff_csv(test_csv: Path, true_csv: Path, zero_tol: float = 3e-10, rel_tol: f
         return f'No lines found in test output {test_csv}'
     if len(true_lines) == 0:
         return f'No lines found in test source {true_csv}'
+    if len(test_lines) != len(true_lines):
+        return f'Number of lines in {test_csv} and {true_csv} do not match'
+
+    # Process commented lines
+    uncommented_lines: List[int] = []
+    for n, (test_line, true_line) in enumerate(zip(test_lines, true_lines)):
+        if test_line[0] == comment_str and true_line[0] == comment_str:
+            if comment_func:
+                output = comment_func(test_line, true_line)
+                if output:
+                    return output
+        elif test_line[0] == comment_str and true_line[0] != comment_str:
+            return f'Commented line found in {test_csv} at line {n} but not in {true_csv}'
+        elif test_line[0] != comment_str and true_line[0] == comment_str:
+            return f'Commented line found in {true_csv} at line {n} but not in {test_csv}'
+        else:
+            uncommented_lines.append(n)
+
+    # Remove commented lines
+    test_lines = [test_lines[line] for line in uncommented_lines]
+    true_lines = [true_lines[line] for line in uncommented_lines]
 
     test_reader: csv.DictReader = csv.DictReader(test_lines)
     true_reader: csv.DictReader = csv.DictReader(true_lines)
@@ -288,8 +321,6 @@ def diff_csv(test_csv: Path, true_csv: Path, zero_tol: float = 3e-10, rel_tol: f
         return ''.join(difflib.unified_diff([f'{test_lines[0]}\n'], [f'{true_lines[0]}\n'],
                        tofile='found CSV columns', fromfile='expected CSV columns'))
 
-    if len(test_lines) != len(true_lines):
-        return f'Number of lines in {test_csv} and {true_csv} do not match'
     diff_lines: List[str] = list()
     for test_line, true_line in zip(test_reader, true_reader):
         for key in test_reader.fieldnames:
@@ -435,7 +466,7 @@ def run_test(index: int, test: str, spec: TestSpec, backend: str,
         ref_csvs: List[Path] = []
         output_files: List[str] = [arg for arg in run_args if 'ascii:' in arg]
         if output_files:
-            ref_csvs = [suite_spec.get_output_path(test, file.split('ascii:')[-1]) for file in output_files]
+            ref_csvs = [suite_spec.get_output_path(test, file.split(':')[1]) for file in output_files]
         ref_cgns: List[Path] = []
         output_files = [arg for arg in run_args if 'cgns:' in arg]
         if output_files:
@@ -484,7 +515,7 @@ def run_test(index: int, test: str, spec: TestSpec, backend: str,
             elif not (Path.cwd() / csv_name).is_file():
                 test_case.add_failure_info('csv', output=f'{csv_name} not found')
             else:
-                diff: str = diff_csv(Path.cwd() / csv_name, ref_csv)
+                diff: str = diff_csv(Path.cwd() / csv_name, ref_csv, **suite_spec.diff_csv_kwargs)
                 if diff:
                     test_case.add_failure_info('csv', output=diff)
                 else: