diff --git a/tests/test_source_release.py b/tests/test_source_release.py
index eb91324..5ad358b 100644
--- a/tests/test_source_release.py
+++ b/tests/test_source_release.py
@@ -805,4 +805,91 @@ def test_strict_accepts_an_executable_regular_payload(self):
         result = build_source_archive(self.repo, self.out, 1700000000, strict_members=True)
         self.assertEqual((result['file_count'], result['release_eligible']), (21, True))
 
+
+class ArchiveRefusalPins(unittest.TestCase):
+    """Refusals that single-point mutants showed unpinned. Reuses the StrictMembers fixture without rerunning its tests."""
+    setUp = StrictMembers.setUp
+    git = StrictMembers.git
+    commit = StrictMembers.commit
+    assert_refused_before_output = StrictMembers.assert_refused_before_output
+    replace_named_commit_with_pending_changes = StrictMembers.replace_named_commit_with_pending_changes
+
+    def test_checkout_only_member_is_named(self):
+        self.git('rm', '-q', 'LICENSE')
+        self.commit('drop LICENSE')
+        (self.repo / 'LICENSE').write_text('synthetic LICENSE\n')
+        self.replace_named_commit_with_pending_changes()
+        self.assert_refused_before_output(
+            re.escape("commit and checkout disagree on members: commit only=[]; checkout only=['LICENSE']") + '$')
+
+    def test_default_call_refuses_private_and_compiled_paths_under_a_listed_name(self):
+        cases = (('__pycache__/module.txt', 'private/generated path refused'),
+                 ('Sandbox/note.txt', 'private/generated path refused'),
+                 ('compiled.pyc', 'compiled payload refused'))
+        for inner, pattern in cases:
+            with self.subTest(path='SUPPORT.md/' + inner):
+                self.git('rm', '-q', 'SUPPORT.md')
+                target = self.repo / 'SUPPORT.md' / inner
+                target.parent.mkdir(parents=True)
+                target.write_text('synthetic descendant\n')
+                self.git('add', '-f', '--', target.relative_to(self.repo).as_posix())
+                self.commit('descendant ' + inner)
+                try:
+                    with self.assertRaisesRegex(ValueError, '^' + pattern):
+                        build_source_archive(self.repo, self.out, 1700000000)
+                    self.assertFalse(self.out.parent.exists())
+                finally:
+                    self.git('reset', '-q', '--hard', 'HEAD~1')
+
+    def test_gitlink_at_a_listed_name_is_refused_as_irregular(self):
+        self.git('rm', '-q', 'LICENSE')
+        self.commit('drop LICENSE')
+        self.git('update-index', '--add', '--cacheinfo', '160000,' + self.git('rev-parse', 'HEAD') + ',LICENSE')
+        (self.repo / 'LICENSE').mkdir()
+        self.git('commit', '-qm', 'gitlink at LICENSE')
+        self.assertEqual(self.git('status', '--porcelain'), '')
+        with self.assertRaisesRegex(ValueError, '^tracked payload is not a regular file: LICENSE$'):
+            build_source_archive(self.repo, self.out, 1700000000)
+
+    def test_invalid_epoch_and_project_metadata_are_refused(self):
+        with self.assertRaisesRegex(ValueError, '^invalid SOURCE_DATE_EPOCH$'):
+            build_source_archive(self.repo, self.out, -1)
+        (self.repo / 'pyproject.toml').write_text('[project]\nname="universal-law-query"\n')
+        self.commit('no version')
+        with self.assertRaisesRegex(ValueError, '^project name/version required$'):
+            build_source_archive(self.repo, self.out, 1700000000)
+        self.assertFalse(self.out.parent.exists())
+
+    def test_failed_git_command_is_reported(self):
+        plain = self.base / 'not-a-repository'
+        plain.mkdir()
+        with mock.patch.dict(os.environ, {'GIT_CEILING_DIRECTORIES': str(self.base)}):
+            with self.assertRaisesRegex(ValueError, '^git command failed'):
+                build_source_archive(plain, self.out, 1700000000)
+
+    def test_non_sha1_commit_is_refused(self):
+        repo = self.base / 'sha256-checkout'
+        repo.mkdir()
+        init = subprocess.run(
+            ['git', 'init', '-q', '--object-format=sha256', str(repo)],
+            capture_output=True, text=True, check=False)
+        if init.returncode:
+            self.skipTest('Git does not support SHA-256 repositories')
+        for name in sorted(ARCHIVE_PAYLOADS):
+            path = repo / name
+            path.parent.mkdir(parents=True, exist_ok=True)
+            path.write_text('synthetic ' + name + '\n')
+        (repo / 'pyproject.toml').write_text('[project]\nname="universal-law-query"\nversion="0.1.0"\n')
+        for args in (('config', 'user.email', 'test@example.com'), ('config', 'user.name', 'test'),
+                     ('add', '-A'), ('commit', '-qm', 'sha256 fixture')):
+            subprocess.run(['git', '-C', str(repo), *args], check=True)
+        with self.assertRaisesRegex(ValueError, '^exact commit required$'):
+            build_source_archive(repo, self.out, 1700000000)
+
+    def test_gzip_header_records_the_source_date_epoch(self):
+        build_source_archive(self.repo, self.out, 1700000000)
+        header = self.out.read_bytes()[:10]
+        self.assertEqual(header[:3], b'\x1f\x8b\x08')
+        self.assertEqual(int.from_bytes(header[4:8], 'little'), 1700000000)
+
 if __name__=='__main__':unittest.main()