test: add linker tests

test/linker.js

@@ -0,0 +1,26 @@
+'use strict'
+
+const test = require('tap').test
+const linker = require('../lib/linker')
+
+test('linker', (t) => {
+
+  /* eslint-disable */
+  const tests = [
+    { i: 'Hello. I opened a PR at https://github.com/nodejs/node/pull/5967'
+    , o: 'Hello. I opened a PR at <a href="https://github.com/nodejs/node/pull/5967" class="external-url external-url-url" target="_blank">nodejs/node#5967</a>'
+    }
+  , { i: 'Hello. Please go to #node.js'
+    , o: 'Hello. Please go to #node.js'
+    }
+  , { i: 'https://github.com/evanlucas/eyearesee/commit/c76d957c967dfd35ee5b876f00bcda11662abba9'
+    , o: '<a href="https://github.com/evanlucas/eyearesee/commit/c76d957c967dfd35ee5b876f00bcda11662abba9" class="external-url external-url-url" target="_blank">evanlucas/eyearesee@c76d957c</a>'
+    }
+  ]
+  /* eslint-enable */
+
+  tests.forEach((item) => {
+    t.equal(linker(item.i), item.o, item.i)
+  })
+  t.end()
+})