[benchmark] ReportFormatter: right-align num cols

Author: palimondo

benchmark/scripts/compare_perf_tests.py

@@ -631,7 +631,9 @@ def row(contents):
         def header(title, column_labels):
             h = ''
             if not self.header_printed:
-                h = '\n' + row(column_labels) + row([HEADER_SEPARATOR] * 5)
+                h = '\n' + row(column_labels)
+                h += row([':' + HEADER_SEPARATOR] +  # left align 1st column
+                         ([HEADER_SEPARATOR + ':']) * 4)  # right align rest
             if self.single_table:
                 h += row(('**' + title + '**', '', '', '', ''))
             if self.single_table and not self.header_printed:

benchmark/scripts/test_compare_perf_tests.py

@@ -759,7 +759,7 @@ def test_column_headers(self):
         )
         self.assert_markdown_contains([
             'TEST                  | OLD    | NEW    | DELTA   | RATIO',
-            '---                   | ---    | ---    | ---     | ---    ',
+            ':---                  | ---:   | ---:   | ---:    | ---:   ',
             'TEST                  | MIN    | MAX    | MEAN    | MAX_RSS'])
         self.assert_git_contains([
             'TEST                    OLD      NEW      DELTA     RATIO',
@@ -864,8 +864,8 @@ def test_single_table_report(self):
             '**Regression**', '**Added**',
             '| OLD', '| NEW', '| DELTA', '| RATIO'
         ], markdown)
-        self.assertIn('\n--- ', markdown)  # first column
-        self.assertEqual(markdown.count('| ---'), 4)
+        self.assertIn('\n:---', markdown)  # first column is left aligned
+        self.assertEqual(markdown.count('| ---:'), 4)  # other, right aligned
 
 
 class Test_parse_args(unittest.TestCase):