checkpoint-assignment data model

lms/migrations/versions/af090ca7e73f_add_assignment_checkpoint_table.py

@@ -0,0 +1,43 @@
+"""Add assignment_checkpoint table."""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "af090ca7e73f"
+down_revision = "b91594c0e379"
+
+
+def upgrade() -> None:
+    op.create_table(
+        "assignment_checkpoint",
+        sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column("assignment_id", sa.Integer(), nullable=False),
+        sa.Column("reveal_date", sa.DateTime(), nullable=True),
+        sa.Column(
+            "created", sa.DateTime(), server_default=sa.func.now(), nullable=False
+        ),
+        sa.Column(
+            "updated", sa.DateTime(), server_default=sa.func.now(), nullable=False
+        ),
+        sa.ForeignKeyConstraint(
+            ["assignment_id"],
+            ["assignment.id"],
+            name=op.f("fk__assignment_checkpoint__assignment_id__assignment"),
+            ondelete="cascade",
+        ),
+        sa.PrimaryKeyConstraint("id", name=op.f("pk__assignment_checkpoint")),
+    )
+    op.create_index(
+        op.f("ix__assignment_checkpoint_assignment_id"),
+        "assignment_checkpoint",
+        ["assignment_id"],
+        unique=False,
+    )
+
+
+def downgrade() -> None:
+    op.drop_index(
+        op.f("ix__assignment_checkpoint_assignment_id"),
+        table_name="assignment_checkpoint",
+    )
+    op.drop_table("assignment_checkpoint")

lms/models/__init__.py

@@ -6,6 +6,7 @@
     AutoGradingConfig,
     AutoGradingType,
 )
+from lms.models.assignment_checkpoint import AssignmentCheckpoint
 from lms.models.assignment_grouping import AssignmentGrouping
 from lms.models.assignment_membership import (
     AssignmentMembership,

lms/models/assignment_checkpoint.py

@@ -0,0 +1,35 @@
+from datetime import datetime
+
+import sqlalchemy as sa
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from lms.db import Base
+from lms.models._mixins import CreatedUpdatedMixin
+
+
+class AssignmentCheckpoint(CreatedUpdatedMixin, Base):
+    """Hide & Reveal configuration for an assignment.
+
+    The existence of a row marks the assignment as a Hide & Reveal assignment
+    (mirroring how a NULL auto_grading_config_id marks a non-auto-graded one).
+
+    Reveal is whole-assignment: a single reveal_date applies to every group the
+    assignment is launched into. This LMS-side row is the source of truth for
+    that reveal state; on each launch the LMS fans it out into one h checkpoint
+    per (group, document) for server-side authorization. The LMS must persist
+    reveal_date here because lti_h.sync blindly re-sends current data on every
+    launch, so without it a re-sync would overwrite h's reveal_date back to NULL
+    and un-reveal an already-revealed assignment.
+    """
+
+    __tablename__ = "assignment_checkpoint"
+
+    id: Mapped[int] = mapped_column(autoincrement=True, primary_key=True)
+
+    assignment_id: Mapped[int] = mapped_column(
+        sa.ForeignKey("assignment.id", ondelete="cascade"), index=True
+    )
+    assignment = relationship("Assignment")
+
+    reveal_date: Mapped[datetime | None] = mapped_column()
+    """When the instructor revealed the assignment; NULL until revealed."""

tests/factories/__init__.py

@@ -5,6 +5,7 @@
 from tests.factories import requests_ as requests
 from tests.factories.application_instance import ApplicationInstance
 from tests.factories.assignment import Assignment, AutoGradingConfig
+from tests.factories.assignment_checkpoint import AssignmentCheckpoint
 from tests.factories.assignment_grouping import AssignmentGrouping
 from tests.factories.assignment_membership import (
     AssignmentMembership,

tests/factories/assignment_checkpoint.py

@@ -0,0 +1,12 @@
+from factory import SubFactory
+from factory.alchemy import SQLAlchemyModelFactory
+
+from lms import models
+from tests.factories.assignment import Assignment
+
+
+class AssignmentCheckpoint(SQLAlchemyModelFactory):
+    class Meta:
+        model = models.AssignmentCheckpoint
+
+    assignment = SubFactory(Assignment)

tests/unit/lms/models/assignment_checkpoint_test.py

@@ -0,0 +1,28 @@
+import pytest
+
+from lms.models import AssignmentCheckpoint
+from tests import factories
+
+
+class TestAssignmentCheckpoint:
+    def test_it(self, db_session, assignment):
+        db_session.commit()  # Ensure our objects have ids
+
+        checkpoint = AssignmentCheckpoint(assignment=assignment)
+        db_session.add(checkpoint)
+
+        db_session.flush()
+        assert checkpoint.assignment == assignment
+        assert checkpoint.assignment_id == assignment.id
+        # reveal_date is NULL until the instructor reveals the assignment.
+        assert checkpoint.reveal_date is None
+
+    def test_factory(self, db_session):
+        checkpoint = factories.AssignmentCheckpoint()
+
+        db_session.flush()
+        assert checkpoint.assignment_id is not None
+
+    @pytest.fixture
+    def assignment(self):
+        return factories.Assignment.create()