diff --git a/dlls/msvcrt/tests/file.c b/dlls/msvcrt/tests/file.c
index f70285b5e8e..5aaaaf71a73 100644
--- a/dlls/msvcrt/tests/file.c
+++ b/dlls/msvcrt/tests/file.c
@@ -106,54 +106,70 @@ static void test_fileops( void )
     int fd;
     FILE *file;
     fpos_t pos;
-    int i, c;
+    int i, c, bufmode;
+    static const int bufmodes[] = {_IOFBF,_IONBF};
 
     fd = open ("fdopen.tst", O_WRONLY | O_CREAT | O_BINARY, _S_IREAD |_S_IWRITE);
     write (fd, outbuffer, sizeof (outbuffer));
     close (fd);
 
-    fd = open ("fdopen.tst", O_RDONLY | O_BINARY);
-    file = fdopen (fd, "rb");
-    ok(strlen(outbuffer) == (sizeof(outbuffer)-1),"strlen/sizeof error\n");
-    ok(fgets(buffer,sizeof(buffer),file) !=0,"fgets failed unexpected\n");
-    ok(fgets(buffer,sizeof(buffer),file) ==0,"fgets didn't signal EOF\n");
-    ok(feof(file) !=0,"feof doesn't signal EOF\n");
-    rewind(file);
-    ok(fgets(buffer,strlen(outbuffer),file) !=0,"fgets failed unexpected\n");
-    ok(lstrlenA(buffer) == lstrlenA(outbuffer) -1,"fgets didn't read right size\n");
-    ok(fgets(buffer,sizeof(outbuffer),file) !=0,"fgets failed unexpected\n");
-    ok(strlen(buffer) == 1,"fgets dropped chars\n");
-    ok(buffer[0] == outbuffer[strlen(outbuffer)-1],"fgets exchanged chars\n");
-
-    rewind(file);
-    for (i = 0, c = EOF; i < sizeof(outbuffer); i++)
+    for (bufmode=0; bufmode < sizeof(bufmodes)/sizeof(bufmodes[0]); bufmode++)
     {
-        ok((c = fgetc(file)) == outbuffer[i], "fgetc returned wrong data\n");
+        fd = open ("fdopen.tst", O_RDONLY | O_BINARY);
+        file = fdopen (fd, "rb");
+        setvbuf(file,NULL,bufmodes[bufmode],2048);
+        ok(strlen(outbuffer) == (sizeof(outbuffer)-1),"strlen/sizeof error for bufmode=%x\n", bufmodes[bufmode]);
+        ok(fgets(buffer,sizeof(buffer),file) !=0,"fgets failed unexpected for bufmode=%x\n", bufmodes[bufmode]);
+        ok(fgets(buffer,sizeof(buffer),file) ==0,"fgets didn't signal EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok(feof(file) !=0,"feof doesn't signal EOF for bufmode=%x\n", bufmodes[bufmode]);
+        rewind(file);
+        ok(fgets(buffer,strlen(outbuffer),file) !=0,"fgets failed unexpected for bufmode=%x\n", bufmodes[bufmode]);
+        ok(lstrlenA(buffer) == lstrlenA(outbuffer) -1,"fgets didn't read right size for bufmode=%x\n", bufmodes[bufmode]);
+        ok(fgets(buffer,sizeof(outbuffer),file) !=0,"fgets failed unexpected for bufmode=%x\n", bufmodes[bufmode]);
+        ok(strlen(buffer) == 1,"fgets dropped chars for bufmode=%x\n", bufmodes[bufmode]);
+        ok(buffer[0] == outbuffer[strlen(outbuffer)-1],"fgets exchanged chars for bufmode=%x\n", bufmodes[bufmode]);
+
+        rewind(file);
+        for (i = 0, c = EOF; i < sizeof(outbuffer); i++)
+        {
+            ok((c = fgetc(file)) == outbuffer[i], "fgetc returned wrong data for bufmode=%x\n", bufmodes[bufmode]);
+        }
+        ok((c = fgetc(file)) == EOF, "getc did not return EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok(feof(file), "feof did not return EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok(ungetc(c, file) == EOF, "ungetc(EOF) did not return EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok(feof(file), "feof after ungetc(EOF) did not return EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok((c = fgetc(file)) == EOF, "getc did not return EOF for bufmode=%x\n", bufmodes[bufmode]);
+        c = outbuffer[sizeof(outbuffer) - 1];
+        if (bufmodes[bufmode] == _IONBF) todo_wine {
+        ok(ungetc(c, file) == c, "ungetc did not return its input for bufmode=%x\n", bufmodes[bufmode]);
+        ok(!feof(file), "feof after ungetc returned EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok((c = fgetc(file)) != EOF, "getc after ungetc returned EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok(c == outbuffer[sizeof(outbuffer) - 1],
+           "getc did not return ungetc'd data for bufmode=%x\n", bufmodes[bufmode]);
+        ok(!feof(file), "feof after getc returned EOF prematurely for bufmode=%x\n", bufmodes[bufmode]);
+        }
+        else
+        {
+        ok(ungetc(c, file) == c, "ungetc did not return its input for bufmode=%x\n", bufmodes[bufmode]);
+        ok(!feof(file), "feof after ungetc returned EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok((c = fgetc(file)) != EOF, "getc after ungetc returned EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok(c == outbuffer[sizeof(outbuffer) - 1],
+           "getc did not return ungetc'd data for bufmode=%x\n", bufmodes[bufmode]);
+        ok(!feof(file), "feof after getc returned EOF prematurely for bufmode=%x\n", bufmodes[bufmode]);
+        }
+        ok((c = fgetc(file)) == EOF, "getc did not return EOF for bufmode=%x\n", bufmodes[bufmode]);
+        ok(feof(file), "feof after getc did not return EOF for bufmode=%x\n", bufmodes[bufmode]);
+
+        rewind(file);
+        ok(fgetpos(file,&pos) == 0, "fgetpos failed unexpected for bufmode=%x\n", bufmodes[bufmode]);
+        ok(pos == 0, "Unexpected result of fgetpos %x%08x for bufmode=%x\n", (DWORD)(pos >> 32), (DWORD)pos, bufmodes[bufmode]);
+        pos = sizeof (outbuffer);
+        ok(fsetpos(file, &pos) == 0, "fsetpos failed unexpected for bufmode=%x\n", bufmodes[bufmode]);
+        ok(fgetpos(file,&pos) == 0, "fgetpos failed unexpected for bufmode=%x\n", bufmodes[bufmode]);
+        ok(pos == sizeof (outbuffer), "Unexpected result of fgetpos %x%08x for bufmode=%x\n", (DWORD)(pos >> 32), (DWORD)pos, bufmodes[bufmode]);
+
+        fclose (file);
     }
-    ok((c = fgetc(file)) == EOF, "getc did not return EOF\n");
-    ok(feof(file), "feof did not return EOF\n");
-    ok(ungetc(c, file) == EOF, "ungetc(EOF) did not return EOF\n");
-    ok(feof(file), "feof after ungetc(EOF) did not return EOF\n");
-    ok((c = fgetc(file)) == EOF, "getc did not return EOF\n");
-    c = outbuffer[sizeof(outbuffer) - 1];
-    ok(ungetc(c, file) == c, "ungetc did not return its input\n");
-    ok(!feof(file), "feof after ungetc returned EOF\n");
-    ok((c = fgetc(file)) != EOF, "getc after ungetc returned EOF\n");
-    ok(c == outbuffer[sizeof(outbuffer) - 1],
-       "getc did not return ungetc'd data\n");
-    ok(!feof(file), "feof after getc returned EOF prematurely\n");
-    ok((c = fgetc(file)) == EOF, "getc did not return EOF\n");
-    ok(feof(file), "feof after getc did not return EOF\n");
-
-    rewind(file);
-    ok(fgetpos(file,&pos) == 0, "fgetpos failed unexpected\n");
-    ok(pos == 0, "Unexpected result of fgetpos %x%08x\n", (DWORD)(pos >> 32), (DWORD)pos);
-    pos = sizeof (outbuffer);
-    ok(fsetpos(file, &pos) == 0, "fsetpos failed unexpected\n");
-    ok(fgetpos(file,&pos) == 0, "fgetpos failed unexpected\n");
-    ok(pos == sizeof (outbuffer), "Unexpected result of fgetpos %x%08x\n", (DWORD)(pos >> 32), (DWORD)pos);
-
-    fclose (file);
     fd = open ("fdopen.tst", O_RDONLY | O_TEXT);
     file = fdopen (fd, "rt"); /* open in TEXT mode */
     ok(fgetws(wbuffer,sizeof(wbuffer)/sizeof(wbuffer[0]),file) !=0,"fgetws failed unexpected\n");