add: cut out trimming text logic for md note title and add unit test

tests/lib/markdown-text-helper-test.js

@@ -0,0 +1,41 @@
+/**
+ * @fileoverview Unit test for browser/lib/markdown
+ */
+const test = require('ava')
+const markdown = require('browser/lib/markdownTextHelper')
+
+test(t => {
+  // [input, expected]
+  const testCases = [
+    // List
+    [' - ', ' '],
+    [' + ', ' '],
+    [' * ', ' '],
+    [' *   ', ' '],
+    [' 1. ', ' '],
+    [' 2.  ', ' '],
+    [' 10. ', ' '],
+    ["\t- ", "\t"],
+    ['- ', ''],
+    // Header with using line
+    ["\n==", "\n"],
+    ["\n===", "\n"],
+    ["test\n===", "test\n"],
+    // Code block
+    ["```test\n", ''],
+    ["```test\nhoge", 'hoge'],
+    // HTML tag
+    ['<>', ''],
+    ['<test>', 'test'],
+    ['hoge<test>', 'hogetest'],
+    ['<test>moge', 'testmoge'],
+    // Emphasis
+    ['~~', ''],
+    ['~~text~~', 'text'],
+  ]
+
+  testCases.forEach(testCase => {
+    const [input, expected] = testCase;
+    t.is(markdown.strip(input), expected, `Test for strip() input: ${input} expected: ${expected}`);
+  })
+})