tests: promote with escaping cases

Author: yasunariw

mock_payloads/commit_comment.mrkdwn_comment.json

@@ -32,7 +32,7 @@
     "created_at": "2020-06-07T15:11:50Z",
     "updated_at": "2020-06-07T15:11:50Z",
     "author_association": "OWNER",
-    "body": "**bold**, *italic*\n> blockquote\n\n* list-element 1\n* list-element 2\n  * list-element2.1\n  * [list-element2.2](www.google.com)\n\n<div>html block</div>\n```ocaml\nStdio.printf \"hello ocaml\"\n```"
+    "body": "**bold**, *italic*\n> blockquote\n\n* list-element 1\n* list-element 2\n  * list-element2.1\n  * [list-element2.2](www.google.com)\n\n<div>html block</div>\n```ocaml\nStdio.printf \"hello ocaml\"\n```\nescaped chars \\\\\\(\\)\\[\\]\\`\\*\n`keep \\`\n```\nkeep \\\n```"
   },
   "repository": {
     "id": 265741348,

test/slack_payloads.expected

@@ -76,7 +76,7 @@ will notify #all-push-events
       "pretext":
         "<https://github.com/xinyuluo/pr_test|[xinyuluo/pr_test]> *xinyuluo* commented on `<https://github.com/xinyuluo/pr_test/commit/cd5b85afa306840e0790b62e349ee1f828b2a3c2#commitcomment-39729580|cd5b85af>` add new line at EOF",
       "text":
-        "this can be written shorter:\n`\n| Some serpDomain -> Domain.is_subdomain serpDomain domain\n| None -> false`",
+        "this can be written shorter:\n`\n| Some serpDomain -&gt; Domain.is_subdomain serpDomain domain\n| None -&gt; false`",
       "footer":
         "New comment by xinyuluo in <https://github.com/xinyuluo/pr_test/commit/cd5b85afa306840e0790b62e349ee1f828b2a3c2#commitcomment-39729580|runner/chat.ml>"
     }
@@ -95,7 +95,7 @@ will notify #all-push-events
       "pretext":
         "<https://github.com/xinyuluo/pr_test|[xinyuluo/pr_test]> *xinyuluo* commented on `<https://github.com/xinyuluo/pr_test/commit/cd5b85afa306840e0790b62e349ee1f828b2a3c2#commitcomment-39729580|cd5b85af>` add new line at EOF",
       "text":
-        "*bold*, _italic_\n\n> blockquote\n\n\n- list-element 1\n- list-element 2\n    - list-element2.1\n    - <www.google.com|list-element2.2>\n\n\n```\n<div>html block</div>\n```\n```\nStdio.printf \"hello ocaml\"\n```",
+        "*bold*, _italic_\n\n> blockquote\n\n\n- list-element 1\n- list-element 2\n    - list-element2.1\n    - <www.google.com|list-element2.2>\n\n\n```\n<div>html block</div>\n```\n```\nStdio.printf \"hello ocaml\"\n```\nescaped chars \\()[]`*\n`keep \\`\n\n```\nkeep \\\n```",
       "footer":
         "New comment by xinyuluo in <https://github.com/xinyuluo/pr_test/commit/cd5b85afa306840e0790b62e349ee1f828b2a3c2#commitcomment-39729580|runner/chat.ml>"
     }