diff --git a/test/test_add_file.py b/test/test_add_file.py
index 2ff499d..1810545 100644
--- a/test/test_add_file.py
+++ b/test/test_add_file.py
@@ -3,6 +3,7 @@ import numpy as np
 from mock import *
 
 from atrcopy import SegmentData, AtariDosDiskImage, InvalidBinaryFile
+from atrcopy.errors import *
 
 
 class TestAtariDosSDImage(object):
@@ -11,6 +12,28 @@ class TestAtariDosSDImage(object):
         rawdata = SegmentData(data)
         self.image = AtariDosDiskImage(rawdata)
 
+    def check_entries(self, entries, save_image_name=None):
+        orig_num_files = len(self.image.files)
+        count = 1
+        for data in entries:
+            filename = "TEST%d.BIN" % count
+            self.image.write_file(filename, None, data)
+            assert len(self.image.files) == orig_num_files + count
+            data2 = self.image.find_file(filename)
+            assert data.tostring() == data2
+            count += 1
+
+        # loop over them again to make sure data wasn't overwritten
+        count = 1
+        for data in entries:
+            filename = "TEST%d.BIN" % count
+            data2 = self.image.find_file(filename)
+            assert data.tostring() == data2
+            count += 1
+
+        if save_image_name is not None:
+            self.image.save(save_image_name)
+
     def test_small(self):
         assert len(self.image.files) == 5
 
@@ -21,6 +44,42 @@ class TestAtariDosSDImage(object):
         data2 = self.image.find_file("TEST.XEX")
         assert data.tostring() == data2
 
+    def test_50k(self):
+        assert len(self.image.files) == 5
+
+        data = np.arange(50*1024, dtype=np.uint8)
+        self.image.write_file("RAMP50K.BIN", None, data)
+        assert len(self.image.files) == 6
+
+        data2 = self.image.find_file("RAMP50K.BIN")
+        assert data.tostring() == data2
+
+    def test_many_small(self):
+        entries = [
+            np.asarray([0xff, 0xff, 0x00, 0x60, 0x01, 0x60, 1, 2], dtype=np.uint8),
+            np.arange(1*1024, dtype=np.uint8),
+            np.arange(2*1024, dtype=np.uint8),
+            np.arange(3*1024, dtype=np.uint8),
+            np.arange(4*1024, dtype=np.uint8),
+            np.arange(5*1024, dtype=np.uint8),
+            np.arange(6*1024, dtype=np.uint8),
+            np.arange(7*1024, dtype=np.uint8),
+            np.arange(8*1024, dtype=np.uint8),
+            np.arange(9*1024, dtype=np.uint8),
+            np.arange(10*1024, dtype=np.uint8),
+            ]
+        self.check_entries(entries, "many_small.atr")
+
+    def test_big_failure(self):
+        assert len(self.image.files) == 5
+
+        data = np.arange(50*1024, dtype=np.uint8)
+        self.image.write_file("RAMP50K.BIN", None, data)
+        assert len(self.image.files) == 6
+        with pytest.raises(NotEnoughSpaceOnDisk):
+            self.image.write_file("RAMP50K2.BIN", None, data)
+        assert len(self.image.files) == 6
+
 
 if __name__ == "__main__":
     t = TestAtariDosFile()