Moved into allmydata.test.test_i2p_provider

This follows the local convention of using mock even though I'm trying to get
rid of mock.  This is because it keeps the test_i2p_provider suite consistent
which means it won't make removing mock from test_i2p_provider later much
harder and lets me avoid doing that work now.

src/allmydata/test/test_connections.py

@@ -174,22 +174,6 @@ class I2P(unittest.TestCase):
             str(ctx.exception)
         )
 
-    def test_launch_executable(self):
-        config = config_from_string(
-            "fake.port",
-            "no-basedir",
-            BASECONFIG + "[i2p]\nlaunch = true\n" + "i2p.executable = i2p\n",
-        )
-        h1 = mock.Mock()
-        with mock.patch("foolscap.connections.i2p.launch",
-                        return_value=h1) as f:
-            i2p_provider = create_i2p_provider(reactor, config)
-            h = i2p_provider.get_i2p_handler()
-            exp = mock.call(i2p_configdir=None, i2p_binary="i2p")
-        self.assertEqual(f.mock_calls, [exp])
-        self.assertIdentical(h, h1)
-
-
 class Connections(unittest.TestCase):
 
     def setUp(self):

src/allmydata/test/test_i2p_provider.py

@@ -277,6 +277,20 @@ class Provider(unittest.TestCase):
         i2p.local_i2p.assert_called_with("configdir")
         self.assertIs(h, handler)
 
+    def test_handler_launch_executable(self):
+        i2p = mock.Mock()
+        handler = object()
+        i2p.launch = mock.Mock(return_value=handler)
+        reactor = object()
+
+        with mock_i2p(i2p):
+            p = i2p_provider.create(reactor,
+                                    FakeConfig(launch=True,
+                                               **{"i2p.executable": "myi2p"}))
+        h = p.get_i2p_handler()
+        self.assertIs(h, handler)
+        i2p.launch.assert_called_with(i2p_configdir=None, i2p_binary="myi2p")
+
     def test_handler_default(self):
         i2p = mock.Mock()
         handler = object()