Improve the test

tests/test_github_retarget_pr.py

@@ -421,15 +421,13 @@ def test_github_retarget_pr_multiple_non_origin_remotes(self, mocker: MockerFixt
 
         self.repo_sandbox.check_out('feature')
         self.repo_sandbox.remove_remote('origin_2')
-        self.repo_sandbox.set_git_config_key("machete.github.prDescriptionIntroStyle", "full")
 
         assert_success(
             ['github', 'retarget-pr', '-U'],
             """
             Base branch of PR #15 has been switched to branch-1
-            Checking for open GitHub PRs... OK
-            Description of PR #15 has been updated
             Updating descriptions of other PRs...
+            Checking for open GitHub PRs... OK
             Description of PR #20 (feature_1 -> feature) has been updated
             Description of PR #25 (feature_2 -> feature) has been updated
             Description of PR #35 (feature_4 -> feature) has been updated
@@ -438,6 +436,21 @@ def test_github_retarget_pr_multiple_non_origin_remotes(self, mocker: MockerFixt
         pr15 = github_api_state.get_pull_by_number(15)
         assert pr15 is not None
         assert pr15['base']['ref'] == 'branch-1'
+        assert pr15['body'] == '# Summary'
+
+        self.repo_sandbox.set_git_config_key("machete.github.prDescriptionIntroStyle", "full")
+        assert_success(
+            ['github', 'retarget-pr', '-U'],
+            """
+            Base branch of PR #15 is already branch-1
+            Checking for open GitHub PRs... OK
+            Description of PR #15 has been updated
+            Updating descriptions of other PRs...
+            """
+        )
+        pr15 = github_api_state.get_pull_by_number(15)
+        assert pr15 is not None
+        assert pr15['base']['ref'] == 'branch-1'
         assert pr15['body'] == textwrap.dedent('''
             <!-- start git-machete generated -->