Fix write.nrrd detached raw nrrd error

* closes natverse#384

Author: jefferis

R/nrrd-io.R

@@ -456,7 +456,7 @@ write.nrrd<-function(x, file, enc=c("gzip","raw","text"),
   if(enc=='text'){
     write(as.vector(x,mode=dmode),ncolumns=1,file=file,append=fmode=='ab')
   } else {
-    fc=ifelse(enc=="gzip", gzfile, file)(file, open=fmode)
+    fc=ifelse(enc=="gzip", gzfile, base::file)(file, open=fmode)
     writeBin(as.vector(x, mode=dmode), fc, size=dtypesize, endian=endian)
     close(fc)
   }

tests/testthat/test-nrrd-io.R

@@ -61,6 +61,12 @@ test_that("read-write.nrrd works",{
   write.nrrd(d,file=tf2, dtype='byte')
   d3=read.nrrd(file=tf2)
   expect_equivalent(d, d3)
+
+  # ... and as raw detached nrrd
+  tf3=tempfile(tmpdir = td, fileext = '.nhdr')
+  write.nrrd(d,file=tf3, dtype='byte', enc='raw')
+  d4=read.nrrd(file=tf3)
+  expect_equivalent(d, d4)
 
   # compare headers
   h=attr(d,'header')