DOC: extended example on usage with functions

README.md

@@ -189,6 +189,37 @@ available: + `__builtins__` : built in python’s functions. +
 `_test_cell_` : `%%testcell` wrapped function executed (we can’t avoid
 this).
 
+``` python
+%%testcell
+def my_function(x):
+    print(aaa) # global variable
+    return x
+
+try:
+    my_function(123)
+except Exception as e:
+    print(e)
+```
+
+    global variable
+
+``` python
+%%testcelln
+def my_function(x):
+    print(aaa) # global variable
+    return x
+
+try:
+    my_function(123)
+except Exception as e:
+    print(e)
+```
+
+    name 'aaa' is not defined
+
+As you can see from this last example, `%%testcelln` helps you to
+identify that `my_function` refers global variable `aaa`.
+
 **IMPORTANT**: this is *just wrapping your cell* and so it’s still
 running on your main kernel. If you modify variables that has been
 created outside of this cell (aka: if you have side effects) this will

nbs/index.ipynb

@@ -474,6 +474,99 @@
     "+ `_test_cell_` : `%%testcell` wrapped function executed (we can't avoid this)."
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "```python\n",
+    "%%testcell\n",
+    "def my_function(x):\n",
+    "    print(aaa) # global variable\n",
+    "    return x\n",
+    "\n",
+    "try:\n",
+    "    my_function(123)\n",
+    "except Exception as e:\n",
+    "    print(e)\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "global variable\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%testcell\n",
+    "#| echo: false\n",
+    "def my_function(x):\n",
+    "    print(aaa) # global variable\n",
+    "    return x\n",
+    "\n",
+    "try:\n",
+    "    my_function(123)\n",
+    "except Exception as e:\n",
+    "    print(e)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "```python\n",
+    "%%testcelln\n",
+    "def my_function(x):\n",
+    "    print(aaa) # global variable\n",
+    "    return x\n",
+    "\n",
+    "try:\n",
+    "    my_function(123)\n",
+    "except Exception as e:\n",
+    "    print(e)\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "name 'aaa' is not defined\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%testcelln\n",
+    "#| echo: false\n",
+    "def my_function(x):\n",
+    "    print(aaa) # global variable\n",
+    "    return x\n",
+    "\n",
+    "try:\n",
+    "    my_function(123)\n",
+    "except Exception as e:\n",
+    "    print(e)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "As you can see from this last example, `%%testcelln` helps you to identify that `my_function` refers global variable `aaa`."
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},