mime/multipart: fix ReadForm always return (nil,io.EOF)ms-fix-multipart-readform

Previously, the condition err == io.EOF in readForm will never true and
break; it always goes to the second condition, err != nil, which
cause the returned ReadForm always nil with err is io.EOF.

As the test, we use the example with body almost similar to
ExampleNewReader with header contains "Content-Disposition:form-data".

Change-Id: I7268f45bb26eafb7f1e6e471b86eec681dde99f7

1 files changed, 7 insertions, 4 deletions

diff --git a/src/net/http/request_test.go b/src/net/http/request_test.go
index 78b968f23c..c952b0ad26 100644
--- a/src/net/http/request_test.go
+++ b/src/net/http/request_test.go
@@ -251,14 +251,17 @@ func TestParseMultipartForm(t *testing.T) {
 		Body:   io.NopCloser(new(bytes.Buffer)),
 	}
 	err := req.ParseMultipartForm(25)
-	if err == nil {
-		t.Error("expected multipart EOF, got nil")
+	if err != nil {
+		t.Errorf("expecting nil, got %v", err)
 	}
 
+	// Reset to allow the call to multipartReader.
+	req.MultipartForm = nil
+
 	req.Header = Header{"Content-Type": {"text/plain"}}
 	err = req.ParseMultipartForm(25)
-	if err != ErrNotMultipart {
-		t.Error("expected ErrNotMultipart for text/plain")
+	if !errors.Is(err, ErrNotMultipart) {
+		t.Errorf("expected ErrNotMultipart for text/plain, got %v", err)
 	}
 }