diff --git a/src/webob/request.py b/src/webob/request.py
index 60e536f0..fd6efeb7 100644
--- a/src/webob/request.py
+++ b/src/webob/request.py
@@ -1570,7 +1570,7 @@ def environ_add_POST(env, data, content_type=None):
         data = list(data.items())
 
         for _, v in data:
-            if isinstance(v, (tuple, list)):
+            if isinstance(v, (tuple, list)) or hasattr(v, 'filename'):
                 has_files = True
 
                 break
diff --git a/tests/test_request.py b/tests/test_request.py
index b4e26ddd..af56b106 100644
--- a/tests/test_request.py
+++ b/tests/test_request.py
@@ -3024,6 +3024,31 @@ def test_fileupload_mime_type_detection(self):
         assert "application/x-foo" in request.body.decode("ascii", str(request))
 
 
+def test_environ_add_POST_file_with_content_type():
+    # For benefit of _encode_multipart which did not have adequate coverage for
+    # type_options
+    class FakeFile:
+        def __init__(self, filename, content_type, type_options, value):
+            self.filename = filename
+            self.type = content_type
+            self.type_options = type_options or {}
+            self.value = value
+
+    from webob.request import environ_from_url, environ_add_POST
+
+    env = environ_from_url("http://example.com/")
+    environ_add_POST(
+        env,
+        {
+            "sample_file":
+            FakeFile("test.txt", "text/plain", {"charset": "utf-8"}, "this is data"),
+        },
+    )
+    wsgi_input = env["wsgi.input"].read()
+    assert b"this is data" in wsgi_input
+    assert b'Content-type: text/plain; charset="utf-8"' in wsgi_input
+
+
 class TestRequestMultipart(object):
     def test_multipart_with_charset(self):
         from webob.request import Request
@@ -3045,6 +3070,7 @@ def simpleapp(environ, start_response):
 
     return [
         bytes_(x)
+
         for x in [
             "Hello world!\n",
             "The get is %r" % request.GET,
@@ -3053,6 +3079,7 @@ def simpleapp(environ, start_response):
             % (
                 [
                     o
+
                     for o, _ in sorted(
                         request.accept_language.parsed or (),
                         key=lambda x: x[1],  # sort by quality
@@ -3064,6 +3091,7 @@ def simpleapp(environ, start_response):
             % ",".join(
                 [
                     o
+
                     for o, _ in request.accept.acceptable_offers(
                         ["application/xml", "text/html"]
                     )