test($shared-utils): complete existed tests of shared-utils (#2366)

* test($shared-utils): cover more cases for unescapeHtml

* test($shared-utils): cover more cases for fileToPath

* test($shared-utils): cover more cases for parseHeaders

packages/@vuepress/shared-utils/__tests__/fileToPath.spec.ts

 import fileToPath from '../src/fileToPath'
 
-test('fileToPath', () => {
+test('should return dirname of the path when it is index file ', () => {
   const asserts: Record<string, string> = {
     'README.md': '/',
+    'README.vue': '/',
     'foo/README.md': '/foo/',
-    'foo.md': '/foo.html',
-    'foo/bar.md': '/foo/bar.html'
+    'foo/README.vue': '/foo/'
   }
   Object.keys(asserts).forEach(file => {
     expect(fileToPath(file)).toBe(asserts[file])
   })
 })
 
+test('should return a path with .html suffix', () => {
+  const asserts: Record<string, string> = {
+    'foo.md': '/foo.html',
+    'foo.vue': '/foo.html',
+    'foo/bar.md': '/foo/bar.html',
+    'foo/bar.vue': '/foo/bar.html'
+  }
+  Object.keys(asserts).forEach(file => {
+    expect(fileToPath(file)).toBe(asserts[file])
+  })
+})

packages/@vuepress/shared-utils/__tests__/parseHeaders.spec.ts

@@ -2,8 +2,8 @@ import parseHeaders from '../src/parseHeaders'
 
 describe('parseHeaders', () => {
   test('should unescape html', () => {
-    const input = '<div>'
-    expect(parseHeaders(input)).toBe('<div>')
+    const input = `&lt;div :id=&quot;&#39;app&#39;&quot;&gt;`
+    expect(parseHeaders(input)).toBe(`<div :id="'app'">`)
   })
 
   test('should remove markdown tokens correctly', () => {

packages/@vuepress/shared-utils/__tests__/unescapeHtml.spec.ts

 import unescapeHtml from '../src/unescapeHtml'
 
 test('should unescape html', () => {
-  const input = '<div>'
-  expect(unescapeHtml(input)).toBe('<div>')
+  const input = `&lt;div :id=&quot;&#39;app&#39;&quot;&gt;`
+  expect(unescapeHtml(input)).toBe(`<div :id="'app'">`)
 })