Added a test for correct behavior

nbgrader/tests/apps/files/validation-zero-points.ipynb

@@ -0,0 +1,75 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Validating this file should fail even though the assignment has 0 points."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "deletable": false,
+    "nbgrader": {
+     "checksum": "8f1eab8d02a9520920aa06f8a86a2492",
+     "grade": false,
+     "grade_id": "squares",
+     "locked": false,
+     "schema_version": 3,
+     "solution": true
+    }
+   },
+   "outputs": [],
+   "source": [
+    "def squares(n):\n",
+    "   # YOUR CODE HERE\n",
+    "    return [0]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "deletable": false,
+    "editable": false,
+    "nbgrader": {
+     "grade": true,
+     "grade_id": "correct_squares",
+     "locked": true,
+     "points": 0,
+     "schema_version": 3,
+     "solution": false,
+     "task": false
+    },
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "assert squares(1) == [1]"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.10"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

nbgrader/tests/apps/test_nbgrader_validate.py

@@ -29,6 +29,12 @@ def test_validate_subdir(self):
         output = run_nbgrader(["validate", "my_subdir/open_relative_file.ipynb"], stdout=True)
         assert output.strip() == "Success! Your notebook passes all the tests."
 
+    def test_validate_zero_points(self):
+      """Does validation correctly fail when cell has zero points?"""
+      self._copy_file(join("files", "validation-zero-points.ipynb"), "validation-zero-points.ipynb")
+      output = run_nbgrader(["validate", "validation-zero-points.ipynb"], stdout=True)
+      assert output.splitlines()[0] == "VALIDATION FAILED ON 1 CELL(S)! If you submit your assignment as it is, you WILL NOT"
+
     def test_invert_validate_unchanged(self):
         """Does the inverted validation pass on an unchanged notebook?"""
         self._copy_file(join("files", "submitted-unchanged.ipynb"), "submitted-unchanged.ipynb")