Add test to check whether -e requirements are correctly packaged.

Previously, requirements with the -e flag where completely ignored
serverless#36

With the latest patch, the -e flag are stripped out, but the
requirement itself is preserved.

This patch adds a check to test this desired behavior.

Author: jacksgt

test.js

@@ -376,6 +376,21 @@ test(
   { skip: !hasPython(3) }
 );
 
+test('py3.6 can package boto3 with editable', t => {
+  process.chdir('tests/base');
+  const path = npm(['pack', '../..']);
+  npm(['i', path]);
+  sls([
+    `--pythonBin=${getPythonBin(3)}`,
+    '--fileName=requirements-w-editable.txt',
+    'package'
+  ]);
+  const zipfiles = listZipFiles('.serverless/sls-py-req-test.zip');
+  t.true(zipfiles.includes(`boto3${sep}__init__.py`), 'boto3 is packaged');
+  t.true(zipfiles.includes(`botocore${sep}__init__.py`), 'botocore is packaged');
+  t.end();
+});
+
 test(
   'py3.6 can package flask with dockerizePip option',
   async t => {

tests/base/requirements-w-editable.txt

@@ -0,0 +1 @@
+-e https://github.com/boto3/boto3#egg=boto3