MAINT: Change test to read random sized chunks

Speeds the test up vs. reading single bytes at a time, and is now
correctly handled when reading the magic string and array header.

1 files changed, 9 insertions, 13 deletions

diff --git a/numpy/lib/tests/test_format.py b/numpy/lib/tests/test_format.py
index dbcdaaaa6..b9be643c8 100644
--- a/numpy/lib/tests/test_format.py
+++ b/numpy/lib/tests/test_format.py
@@ -411,16 +411,12 @@ record_arrays = [
 ]
 
 
-#BytesIO that reads a single byte at a time
-class BytesIOSingleByte(BytesIO):
+#BytesIO that reads a random number of bytes at a time
+class BytesIOSRandomSize(BytesIO):
     def read(self, size=None):
-        #Return first 512 bytes normally, otherwise checking magic bytes
-        #and reading header fails
-        if self.tell() > 512:
-            size = 1
-        else:
-            size = min(size, 512)
-        return super(BytesIOSingleByte, self).read(size)
+        import random
+        size = random.randint(1, size)
+        return super(BytesIOSRandomSize, self).read(size)
 
 
 def roundtrip(arr):
@@ -431,10 +427,10 @@ def roundtrip(arr):
     return arr2
 
 
-def roundtrip_onebyte(arr):
+def roundtrip_randsize(arr):
     f = BytesIO()
     format.write_array(f, arr)
-    f2 = BytesIOSingleByte(f.getvalue())
+    f2 = BytesIOSRandomSize(f.getvalue())
     arr2 = format.read_array(f2)
     return arr2
 
@@ -458,10 +454,10 @@ def test_roundtrip():
         yield assert_array_equal, arr, arr2
 
 
-def test_roundtrip_onebyte():
+def test_roundtrip_randsize():
     for arr in basic_arrays + record_arrays:
         if arr.dtype != object:
-            arr2 = roundtrip_onebyte(arr)
+            arr2 = roundtrip_randsize(arr)
             yield assert_array_equal, arr, arr2