feat: init pg migration

tests/core/test_db_uri.py

@@ -0,0 +1,144 @@
+"""Tests for ``application.core.db_uri``.
+
+DocsGPT has two Postgres connection strings — ``POSTGRES_URI`` (consumed
+by SQLAlchemy) and ``PGVECTOR_CONNECTION_STRING`` (consumed by
+``psycopg.connect()`` directly). They need opposite normalization
+because SQLAlchemy requires a ``postgresql+psycopg://`` dialect prefix
+and libpq rejects it. Each field has its own normalizer so operators
+can write whichever form feels natural and cross-pollination between
+the two fields is forgiven.
+
+The normalizers live in ``application.core.db_uri`` as plain functions
+so these tests can exercise them directly without having to instantiate
+``Settings`` (which would pull in ``.env`` file side effects).
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from application.core.db_uri import (
+    normalize_pgvector_connection_string,
+    normalize_postgres_uri,
+)
+
+
+@pytest.mark.unit
+class TestNormalizePostgresUri:
+    @pytest.mark.parametrize(
+        "input_value,expected",
+        [
+            # User-friendly forms get rewritten to the SQLAlchemy dialect.
+            (
+                "postgres://u:p@h:5432/d",
+                "postgresql+psycopg://u:p@h:5432/d",
+            ),
+            (
+                "postgresql://u:p@h:5432/d",
+                "postgresql+psycopg://u:p@h:5432/d",
+            ),
+            # Legacy psycopg2 dialect is silently upgraded — psycopg2 is
+            # no longer in requirements.txt, so there's no way it can work
+            # as-is, and rewriting is friendlier than failing.
+            (
+                "postgresql+psycopg2://u:p@h:5432/d",
+                "postgresql+psycopg://u:p@h:5432/d",
+            ),
+            # Already-correct dialect passes through unchanged.
+            (
+                "postgresql+psycopg://u:p@h:5432/d",
+                "postgresql+psycopg://u:p@h:5432/d",
+            ),
+            # Whitespace is trimmed before rewriting.
+            (
+                "  postgres://u:p@h/d  ",
+                "postgresql+psycopg://u:p@h/d",
+            ),
+            # Query-string params (sslmode, options) are preserved verbatim.
+            (
+                "postgresql://u:p@h:5432/d?sslmode=require&application_name=docsgpt",
+                "postgresql+psycopg://u:p@h:5432/d?sslmode=require&application_name=docsgpt",
+            ),
+        ],
+    )
+    def test_rewrites_common_forms_to_psycopg_dialect(self, input_value, expected):
+        assert normalize_postgres_uri(input_value) == expected
+
+    @pytest.mark.parametrize(
+        "input_value",
+        [None, "", "   ", "None", "none"],
+    )
+    def test_empty_or_none_like_returns_none(self, input_value):
+        assert normalize_postgres_uri(input_value) is None
+
+    def test_unknown_scheme_passes_through(self):
+        """A dialect we don't recognise is left alone so SQLAlchemy can
+        produce its own error message when the engine tries to connect.
+        Better than silently eating the config."""
+        weird = "postgresql+asyncpg://u:p@h/d"
+        assert normalize_postgres_uri(weird) == weird
+
+    def test_non_string_input_passes_through(self):
+        """Non-string inputs (e.g. if pydantic ever passes an int) shouldn't
+        crash the normalizer — let pydantic's own type validation handle it."""
+        assert normalize_postgres_uri(42) == 42  # type: ignore[arg-type]
+
+
+@pytest.mark.unit
+class TestNormalizePgvectorConnectionString:
+    """Symmetric to the POSTGRES_URI normalizer but pulls in the OPPOSITE
+    direction: strips the SQLAlchemy dialect prefix so libpq accepts it.
+    """
+
+    @pytest.mark.parametrize(
+        "input_value,expected",
+        [
+            # User-friendly forms pass through — libpq accepts them natively.
+            (
+                "postgres://u:p@h:5432/d",
+                "postgres://u:p@h:5432/d",
+            ),
+            (
+                "postgresql://u:p@h:5432/d",
+                "postgresql://u:p@h:5432/d",
+            ),
+            # SQLAlchemy dialect prefixes get stripped so libpq accepts them.
+            # Operators hit this when they copy POSTGRES_URI → PGVECTOR_CONNECTION_STRING.
+            (
+                "postgresql+psycopg://u:p@h:5432/d",
+                "postgresql://u:p@h:5432/d",
+            ),
+            (
+                "postgresql+psycopg2://u:p@h:5432/d",
+                "postgresql://u:p@h:5432/d",
+            ),
+            # Whitespace is trimmed before rewriting.
+            (
+                "  postgresql+psycopg://u:p@h/d  ",
+                "postgresql://u:p@h/d",
+            ),
+            # Query-string params (sslmode, etc.) are preserved verbatim.
+            (
+                "postgresql+psycopg://u:p@h:5432/d?sslmode=require",
+                "postgresql://u:p@h:5432/d?sslmode=require",
+            ),
+        ],
+    )
+    def test_rewrites_dialect_forms_to_libpq_compatible(self, input_value, expected):
+        assert normalize_pgvector_connection_string(input_value) == expected
+
+    @pytest.mark.parametrize(
+        "input_value",
+        [None, "", "   ", "None", "none"],
+    )
+    def test_empty_or_none_like_returns_none(self, input_value):
+        assert normalize_pgvector_connection_string(input_value) is None
+
+    def test_unknown_scheme_passes_through(self):
+        """A scheme we don't recognise is left alone so libpq can produce
+        its own error message when the connection is attempted."""
+        weird = "mysql://u:p@h/d"
+        assert normalize_pgvector_connection_string(weird) == weird
+
+    def test_non_string_input_passes_through(self):
+        assert normalize_pgvector_connection_string(42) == 42  # type: ignore[arg-type]