Improve branch coverage for numpyclient

tests/test_numpyclient.py

@@ -150,12 +150,14 @@ class TestNumpyClient(object):
             client.stream_extract_numpy(
                 "/newton/prep", structured = False, maxrows = 1000))
 
-        # Structured, and specifying layout
+        # Structured, and specifying layout.
+        # This also tests the final branch in stream_extract_numpy by specifing
+        # a value of maxrows that exactly matches how much data we had inserted.
         client.stream_create("/test/3", "float32_8")
         client.stream_insert_numpy(
             path = "/test/3", layout = "float32_8",
             data = client.stream_extract_numpy(
-                "/newton/prep", structured = True, maxrows = 1000))
+                "/newton/prep", structured = True, maxrows = 14400))
 
         # Structured, specifying wrong layout
         client.stream_create("/test/4", "float32_8")