Change MultipartFile.fromFile to MultipartFile.fromPath in pkg/http.

pkg/http/test/multipart_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library multipart_test;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:utf';
 
+import 'package:pathos/path.dart' as path;
 import 'package:unittest/unittest.dart';
 import 'package:http/http.dart' as http;
 import 'package:http/src/utils.dart';
 
 import 'utils.dart';
 
 /// A matcher that validates the body of a multipart request after finalization.
 /// The string "{{boundary}}" in [pattern] will be replaced by the boundary
 /// string for the request, and LF newlines will be replaced with CRLF.
 /// Indentation will be normalized.
@@ skipping 174 matching lines @@
 
     expect(request, bodyMatches('''
         --{{boundary}}
         content-type: application/octet-stream
         content-disposition: form-data; name="file"
 
         hello
         --{{boundary}}--
         '''));
   });
+
+  test('with a file from disk', () {
+    var tempDir = new Directory('').createTempSync();
+
+    expect(new Future.of(() {
+      var filePath = path.join(tempDir.path, 'test-file');
+      new File(filePath).writeAsStringSync('hello');
+      return http.MultipartFile.fromPath('file', filePath);
+    }).then((file) {
+      var request = new http.MultipartRequest('POST', dummyUrl);
+      request.files.add(file);
+
+      expect(request, bodyMatches('''
+        --{{boundary}}
+        content-type: application/octet-stream
+        content-disposition: form-data; name="file"; filename="test-file"
+
+        hello
+        --{{boundary}}--
+        '''));
+    }).whenComplete(() => tempDir.delete(recursive: true)), completes);
+  });
 }