Move markdown dest files check to StoreReport for earlier error and parser.error style output

Author: marcosboger

src/pytest_cov/engine.py

@@ -16,7 +16,6 @@
 
 import coverage
 from coverage.data import CoverageData
-from coverage.misc import CoverageException
 from coverage.sqldata import filename_suffix
 
 from . import CentralCovContextWarning
@@ -256,26 +255,17 @@ def summary(self, stream):
                 total = self.cov.json_report(ignore_errors=True, outfile=output)
             stream.write('Coverage JSON written to file %s\n' % (self.cov.config.json_output if output is None else output))
 
-        # Check that markdown and markdown-append don't point to same file
-        if all(x in self.cov_report for x in ['markdown', 'markdown-append']):
-            markdown_file = self.cov_report['markdown'] or 'coverage.md'
-            markdown_append_file = self.cov_report['markdown-append'] or 'coverage.md'
-            if markdown_file == markdown_append_file:
-                error_message = f"markdown and markdown-append options cannot point to the same file: '{markdown_file}'."
-                error_message += ' Please redirect one of them using :DEST (e.g. --cov-report=markdown:dest_file.md)'
-                raise CoverageException(error_message)
-
         # Produce Markdown report if wanted.
         if 'markdown' in self.cov_report:
-            output = self.cov_report['markdown'] or 'coverage.md'
+            output = self.cov_report['markdown']
             with _backup(self.cov, 'config'):
                 with Path(output).open('w') as output_file:
                     total = self.cov.report(ignore_errors=True, file=output_file, output_format='markdown')
             stream.write(f'Coverage Markdown information written to file {output}\n')
 
         # Produce Markdown report if wanted, appending to output file
         if 'markdown-append' in self.cov_report:
-            output = self.cov_report['markdown-append'] or 'coverage.md'
+            output = self.cov_report['markdown-append']
             with _backup(self.cov, 'config'):
                 with Path(output).open('a') as output_file:
                     total = self.cov.report(ignore_errors=True, file=output_file, output_format='markdown')

src/pytest_cov/plugin.py

@@ -82,6 +82,20 @@ def __call__(self, parser, namespace, values, option_string=None):
         report_type, file = values
         namespace.cov_report[report_type] = file
 
+        # coverage.py doesn't set a default file for markdown output_format
+        if report_type in ['markdown', 'markdown-append'] and file is None:
+            namespace.cov_report[report_type] = 'coverage.md'
+        if all(x in namespace.cov_report for x in ['markdown', 'markdown-append']):
+            self._validate_markdown_dest_files(namespace.cov_report, parser)
+
+    def _validate_markdown_dest_files(self, cov_report_options, parser):
+        markdown_file = cov_report_options['markdown']
+        markdown_append_file = cov_report_options['markdown-append']
+        if markdown_file == markdown_append_file:
+            error_message = f"markdown and markdown-append options cannot point to the same file: '{markdown_file}'."
+            error_message += ' Please redirect one of them using :DEST (e.g. --cov-report=markdown:dest_file.md)'
+            parser.error(error_message)
+
 
 def pytest_addoption(parser):
     """Add options to control coverage."""

tests/test_pytest_cov.py

@@ -417,7 +417,7 @@ def test_markdown_and_markdown_append_work_together(testdir):
     assert result.ret == 0
 
 
-def test_markdown_and_markdown_append_pointing_to_same_file_throws_warning(testdir):
+def test_markdown_and_markdown_append_pointing_to_same_file_throws_error(testdir):
     script = testdir.makepyfile(SCRIPT)
 
     result = testdir.runpytest(
@@ -428,8 +428,8 @@ def test_markdown_and_markdown_append_pointing_to_same_file_throws_warning(testd
         script,
     )
 
-    result.stdout.fnmatch_lines(['*WARNING: Failed to generate report: *', '*_ coverage: platform *, python * _*'])
-    assert result.ret == 0
+    result.stderr.fnmatch_lines(['* error: markdown and markdown-append options cannot point to the same file*'])
+    assert result.ret == 4
 
 
 @pytest.mark.skipif('coverage.version_info < (6, 3)')