From 29a8c68c5d05181256c3422326b8001086de672d Mon Sep 17 00:00:00 2001
From: Mike Del Tito <mike.deltito@logdna.com>
Date: Fri, 28 May 2021 17:13:34 -0400
Subject: [PATCH] feat(rules): add no-multiple-empty-lines rule

This prevents multiple empty/blank lines, which comes up semi-often
in code review

Ref: LOG-9871
---
 .eslintrc.json                                |  1 +
 test/failures.js                              | 13 +++++++++++++
 test/fixtures/no-multiple-empty-lines-fixture |  8 ++++++++
 3 files changed, 22 insertions(+)
 create mode 100644 test/fixtures/no-multiple-empty-lines-fixture

diff --git a/.eslintrc.json b/.eslintrc.json
index a42e589..84e3de7 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -133,6 +133,7 @@
     }],
     "no-loop-func": 2,
     "no-mixed-spaces-and-tabs": 2,
+    "no-multiple-empty-lines": [2, {"max": 1}],
     "no-multi-spaces": 2,
     "no-multi-str": 2,
     "no-native-reassign": 0,
diff --git a/test/failures.js b/test/failures.js
index bde504b..b01ae6a 100644
--- a/test/failures.js
+++ b/test/failures.js
@@ -30,6 +30,19 @@ test('Invalid linting for larger code blocks read from fixtures', async (t) => {
     )
   })
 
+  t.test('no-multiple-empty-lines', async (t) => {
+    const result = cli.executeOnFiles(['no-multiple-empty-lines-fixture'])
+    t.equal(result.errorCount, 1, 'error count')
+    const messages = result.results[0].messages
+
+    t.equal(messages[0].ruleId, 'no-multiple-empty-lines', 'multiple empty found')
+    t.match(
+      messages[0].message
+    , /more than 1 blank line not allowed/ig
+    , 'message expected multiple empty'
+    )
+  })
+
   t.test('no-debugger', async (t) => {
     const result = cli.executeOnFiles(['no-debugger-fixture'])
     t.equal(result.errorCount, 1, 'error count')
diff --git a/test/fixtures/no-multiple-empty-lines-fixture b/test/fixtures/no-multiple-empty-lines-fixture
new file mode 100644
index 0000000..39cd716
--- /dev/null
+++ b/test/fixtures/no-multiple-empty-lines-fixture
@@ -0,0 +1,8 @@
+'use strict'
+
+module.exports = fooBar
+
+
+function fooBar() {
+  return true
+}