[FastAPI] Refactor db modifications

For SQLAlchemy to automatically understand updates from the
external world, it must use an `autocommit=True` in its session.

This change breaks how we were using commit previously, as
`autocommit=True` causes SQLAlchemy to commit when a
SessionTransaction context hits __exit__.

So, a refactoring was required of our tests: All usage of
any `db.{create,delete}` must be called **within** a
SessionTransaction context, created via new `db.begin()`.

From this point forward, we're going to require:

```
with db.begin():
    db.create(...)
    db.delete(...)
    db.session.delete(object)
```

With this, we now get external DB modifications automatically
without reloading or restarting the FastAPI server, which we
absolutely need for production.

Signed-off-by: Kevin Morris <kevr@0cost.org>

test/test_ssh_pub_key.py

@@ -1,6 +1,6 @@
 import pytest
 
-from aurweb.db import create, query
+from aurweb import db
 from aurweb.models.account_type import AccountType
 from aurweb.models.ssh_pub_key import SSHPubKey, get_fingerprint
 from aurweb.models.user import User
@@ -19,19 +19,18 @@ def setup():
 
     setup_test_db("Users", "SSHPubKeys")
 
-    account_type = query(AccountType,
-                         AccountType.AccountType == "User").first()
-    user = create(User, Username="test", Email="test@example.org",
-                  RealName="Test User", Passwd="testPassword",
-                  AccountType=account_type)
+    account_type = db.query(AccountType,
+                            AccountType.AccountType == "User").first()
+    with db.begin():
+        user = db.create(User, Username="test", Email="test@example.org",
+                         RealName="Test User", Passwd="testPassword",
+                         AccountType=account_type)
 
-    assert account_type == user.AccountType
-    assert account_type.ID == user.AccountTypeID
-
-    ssh_pub_key = create(SSHPubKey,
-                         UserID=user.ID,
-                         Fingerprint="testFingerprint",
-                         PubKey="testPubKey")
+    with db.begin():
+        ssh_pub_key = db.create(SSHPubKey,
+                                UserID=user.ID,
+                                Fingerprint="testFingerprint",
+                                PubKey="testPubKey")
 
 
 def test_ssh_pub_key():
@@ -43,9 +42,10 @@ def test_ssh_pub_key():
 
 def test_ssh_pub_key_cs():
     """ Test case sensitivity of the database table. """
-    ssh_pub_key_cs = create(SSHPubKey, UserID=user.ID,
-                            Fingerprint="TESTFINGERPRINT",
-                            PubKey="TESTPUBKEY")
+    with db.begin():
+        ssh_pub_key_cs = db.create(SSHPubKey, UserID=user.ID,
+                                   Fingerprint="TESTFINGERPRINT",
+                                   PubKey="TESTPUBKEY")
 
     assert ssh_pub_key_cs.Fingerprint == "TESTFINGERPRINT"
     assert ssh_pub_key_cs.PubKey == "TESTPUBKEY"