fixed coll_repr printing incorrectly when max_n!=10, and added relevant tests

Author: kessido

fastcore/foundation.py

@@ -86,7 +86,7 @@ def docs(cls):
 def coll_repr(c, max_n=10):
     "String repr of up to `max_n` items of (possibly lazy) collection `c`"
     return f'(#{len(c)}) [' + ','.join(itertools.islice(map(repr,c), max_n)) + (
-        '...' if len(c)>10 else '') + ']'
+        '...' if len(c)>max_n else '') + ']'
 
 # Cell
 def is_bool(x):

nbs/02_foundation.ipynb

@@ -613,7 +613,7 @@
     "def coll_repr(c, max_n=10):\n",
     "    \"String repr of up to `max_n` items of (possibly lazy) collection `c`\"\n",
     "    return f'(#{len(c)}) [' + ','.join(itertools.islice(map(repr,c), max_n)) + (\n",
-    "        '...' if len(c)>10 else '') + ']'"
+    "        '...' if len(c)>max_n else '') + ']'"
    ]
   },
   {
@@ -631,7 +631,10 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "test_eq(coll_repr(range(1000)), '(#1000) [0,1,2,3,4,5,6,7,8,9...]')"
+    "test_eq(coll_repr(range(1000)),    '(#1000) [0,1,2,3,4,5,6,7,8,9...]')\n",
+    "test_eq(coll_repr(range(1000),5),  '(#1000) [0,1,2,3,4...]')\n",
+    "test_eq(coll_repr(range(10),5),      '(#10) [0,1,2,3,4...]')\n",
+    "test_eq(coll_repr(range(5),5),        '(#5) [0,1,2,3,4]')"
    ]
   },
   {