Make file-admin test easier to extend

Currently the unit tests for file-admin are tied to the local
implementation. However, all other implementations of the file-admin
(e..g S3) should maintain the same invariants as the local one. As such,
this change makes it easier to copy the local file-admin tests for other
storage backends.

flask_admin/tests/fileadmin/test_fileadmin.py

 import os.path as op
+import unittest
 
 from nose.tools import eq_, ok_
 
@@ -14,21 +15,30 @@ except ImportError:
     from io import StringIO
 
 
-def create_view():
-    app, admin = setup()
+class Base:
+    class FileAdminTests(unittest.TestCase):
+        _test_files_root = op.join(op.dirname(__file__), 'files')
 
-    class MyFileAdmin(fileadmin.FileAdmin):
-        editable_extensions = ('txt',)
+        def fileadmin_class(self):
+            raise NotImplementedError
 
-    path = op.join(op.dirname(__file__), 'files')
-    view = MyFileAdmin(path, '/files/', name='Files')
-    admin.add_view(view)
+        def fileadmin_args(self):
+            raise NotImplementedError
+
+        def test_file_admin(self):
+            fileadmin_class = self.fileadmin_class()
+            fileadmin_args, fileadmin_kwargs = self.fileadmin_args()
 
-    return app, admin, view
+            app, admin = setup()
+
+            class MyFileAdmin(fileadmin_class):
+                editable_extensions = ('txt',)
 
+            view_kwargs = dict(fileadmin_kwargs)
+            view_kwargs.setdefault('name', 'Files')
+            view = MyFileAdmin(*fileadmin_args, **view_kwargs)
 
-def test_file_admin():
-    app, admin, view = create_view()
+            admin.add_view(view)
 
             client = app.test_client()
 
@@ -42,9 +52,8 @@ def test_file_admin():
             eq_(rv.status_code, 200)
             ok_('dummy.txt' in rv.data.decode('utf-8'))
 
-    rv = client.post('/admin/myfileadmin/edit/?path=dummy.txt', data=dict(
-        content='new_string'
-    ))
+            rv = client.post('/admin/myfileadmin/edit/?path=dummy.txt',
+                             data=dict(content='new_string'))
             eq_(rv.status_code, 302)
 
             rv = client.get('/admin/myfileadmin/edit/?path=dummy.txt')
@@ -57,10 +66,9 @@ def test_file_admin():
             eq_(rv.status_code, 200)
             ok_('dummy.txt' in rv.data.decode('utf-8'))
 
-    rv = client.post('/admin/myfileadmin/rename/?path=dummy.txt', data=dict(
-        name='dummy_renamed.txt',
-        path='dummy.txt'
-    ))
+            rv = client.post('/admin/myfileadmin/rename/?path=dummy.txt',
+                             data=dict(name='dummy_renamed.txt',
+                                       path='dummy.txt'))
             eq_(rv.status_code, 302)
 
             rv = client.get('/admin/myfileadmin/')
@@ -72,9 +80,8 @@ def test_file_admin():
             rv = client.get('/admin/myfileadmin/upload/')
             eq_(rv.status_code, 200)
 
-    rv = client.post('/admin/myfileadmin/upload/', data=dict(
-        upload=(StringIO(""), 'dummy.txt'),
-    ))
+            rv = client.post('/admin/myfileadmin/upload/',
+                             data=dict(upload=(StringIO(""), 'dummy.txt')))
             eq_(rv.status_code, 302)
 
             rv = client.get('/admin/myfileadmin/')
@@ -83,9 +90,8 @@ def test_file_admin():
             ok_('path=dummy_renamed.txt' in rv.data.decode('utf-8'))
 
             # delete
-    rv = client.post('/admin/myfileadmin/delete/', data=dict(
-        path='dummy_renamed.txt'
-    ))
+            rv = client.post('/admin/myfileadmin/delete/',
+                             data=dict(path='dummy_renamed.txt'))
             eq_(rv.status_code, 302)
 
             rv = client.get('/admin/myfileadmin/')
@@ -97,9 +103,8 @@ def test_file_admin():
             rv = client.get('/admin/myfileadmin/mkdir/')
             eq_(rv.status_code, 200)
 
-    rv = client.post('/admin/myfileadmin/mkdir/', data=dict(
-        name='dummy_dir'
-    ))
+            rv = client.post('/admin/myfileadmin/mkdir/',
+                             data=dict(name='dummy_dir'))
             eq_(rv.status_code, 302)
 
             rv = client.get('/admin/myfileadmin/')
@@ -112,10 +117,9 @@ def test_file_admin():
             eq_(rv.status_code, 200)
             ok_('dummy_dir' in rv.data.decode('utf-8'))
 
-    rv = client.post('/admin/myfileadmin/rename/?path=dummy_dir', data=dict(
-        name='dummy_renamed_dir',
-        path='dummy_dir'
-    ))
+            rv = client.post('/admin/myfileadmin/rename/?path=dummy_dir',
+                             data=dict(name='dummy_renamed_dir',
+                                       path='dummy_dir'))
             eq_(rv.status_code, 302)
 
             rv = client.get('/admin/myfileadmin/')
@@ -124,9 +128,8 @@ def test_file_admin():
             ok_('path=dummy_dir' not in rv.data.decode('utf-8'))
 
             # delete - directory
-    rv = client.post('/admin/myfileadmin/delete/', data=dict(
-        path='dummy_renamed_dir'
-    ))
+            rv = client.post('/admin/myfileadmin/delete/',
+                             data=dict(path='dummy_renamed_dir'))
             eq_(rv.status_code, 302)
 
             rv = client.get('/admin/myfileadmin/')
@@ -134,30 +137,37 @@ def test_file_admin():
             ok_('path=dummy_renamed_dir' not in rv.data.decode('utf-8'))
             ok_('path=dummy.txt' in rv.data.decode('utf-8'))
 
-
-def test_modal_edit():
+        def test_modal_edit(self):
             # bootstrap 2 - test edit_modal
             app_bs2 = Flask(__name__)
             admin_bs2 = Admin(app_bs2, template_mode="bootstrap2")
 
-    class EditModalOn(fileadmin.FileAdmin):
+            fileadmin_class = self.fileadmin_class()
+            fileadmin_args, fileadmin_kwargs = self.fileadmin_args()
+
+            class EditModalOn(fileadmin_class):
                 edit_modal = True
                 editable_extensions = ('txt',)
 
-    class EditModalOff(fileadmin.FileAdmin):
+            class EditModalOff(fileadmin_class):
                 edit_modal = False
                 editable_extensions = ('txt',)
 
-    path = op.join(op.dirname(__file__), 'files')
-    edit_modal_on = EditModalOn(path, '/files/', endpoint='edit_modal_on')
-    edit_modal_off = EditModalOff(path, '/files/', endpoint='edit_modal_off')
+            on_view_kwargs = dict(fileadmin_kwargs)
+            on_view_kwargs.setdefault('endpoint', 'edit_modal_on')
+            edit_modal_on = EditModalOn(*fileadmin_args, **on_view_kwargs)
+
+            off_view_kwargs = dict(fileadmin_kwargs)
+            off_view_kwargs.setdefault('endpoint', 'edit_modal_off')
+            edit_modal_off = EditModalOff(*fileadmin_args, **off_view_kwargs)
 
             admin_bs2.add_view(edit_modal_on)
             admin_bs2.add_view(edit_modal_off)
 
             client_bs2 = app_bs2.test_client()
 
-    # bootstrap 2 - ensure modal window is added when edit_modal is enabled
+            # bootstrap 2 - ensure modal window is added when edit_modal is
+            # enabled
             rv = client_bs2.get('/admin/edit_modal_on/')
             eq_(rv.status_code, 200)
             data = rv.data.decode('utf-8')
@@ -178,7 +188,8 @@ def test_modal_edit():
 
             client_bs3 = app_bs3.test_client()
 
-    # bootstrap 3 - ensure modal window is added when edit_modal is enabled
+            # bootstrap 3 - ensure modal window is added when edit_modal is
+            # enabled
             rv = client_bs3.get('/admin/edit_modal_on/')
             eq_(rv.status_code, 200)
             data = rv.data.decode('utf-8')
@@ -189,3 +200,11 @@ def test_modal_edit():
             eq_(rv.status_code, 200)
             data = rv.data.decode('utf-8')
             ok_('fa_modal_window' not in data)
+
+
+class LocalFileAdminTests(Base.FileAdminTests):
+    def fileadmin_class(self):
+        return fileadmin.FileAdmin
+
+    def fileadmin_args(self):
+        return (self._test_files_root, '/files'), {}