From d3c36e30d5183195fbb506f6436f12dc7f58ea37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lu=C3=ADs=20Murta?= <luis@murta.dev>
Date: Mon, 17 Apr 2023 19:52:52 +0100
Subject: [PATCH] [Refactor] Creates Transform interface

Moves categorizer into transform module.
Puts the categorizer under unit tests.
---
 pfbudget/core/manager.py                    |  2 +-
 pfbudget/{core => transform}/categorizer.py |  0
 pfbudget/transform/transform.py             | 10 ++++
 tests/mocks/categories.py                   | 11 +++++
 tests/test_transform.py                     | 52 +++++++++++++++++++++
 5 files changed, 74 insertions(+), 1 deletion(-)
 rename pfbudget/{core => transform}/categorizer.py (100%)
 create mode 100644 pfbudget/transform/transform.py
 create mode 100644 tests/mocks/categories.py
 create mode 100644 tests/test_transform.py

diff --git a/pfbudget/core/manager.py b/pfbudget/core/manager.py
index 2dcf45c..779212b 100644
--- a/pfbudget/core/manager.py
+++ b/pfbudget/core/manager.py
@@ -4,7 +4,6 @@ import pickle
 import webbrowser
 
 from pfbudget.common.types import Operation
-from pfbudget.core.categorizer import Categorizer
 from pfbudget.db.client import DbClient
 from pfbudget.db.model import (
     Bank,
@@ -28,6 +27,7 @@ from pfbudget.db.model import (
 from pfbudget.extract.nordigen import NordigenClient, NordigenCredentialsManager
 from pfbudget.extract.parsers import parse_data
 from pfbudget.extract.psd2 import PSD2Extractor
+from pfbudget.transform.categorizer import Categorizer
 
 
 class Manager:
diff --git a/pfbudget/core/categorizer.py b/pfbudget/transform/categorizer.py
similarity index 100%
rename from pfbudget/core/categorizer.py
rename to pfbudget/transform/categorizer.py
diff --git a/pfbudget/transform/transform.py b/pfbudget/transform/transform.py
new file mode 100644
index 0000000..7dbb0a2
--- /dev/null
+++ b/pfbudget/transform/transform.py
@@ -0,0 +1,10 @@
+from abc import ABC, abstractmethod
+from typing import Sequence
+
+from pfbudget.db.model import Transaction
+
+
+class Transformer(ABC):
+    @abstractmethod
+    def transform(self, _: Sequence[Transaction]) -> Sequence[Transaction]:
+        raise NotImplementedError
diff --git a/tests/mocks/categories.py b/tests/mocks/categories.py
new file mode 100644
index 0000000..f111ea3
--- /dev/null
+++ b/tests/mocks/categories.py
@@ -0,0 +1,11 @@
+from decimal import Decimal
+
+from pfbudget.db.model import Category, CategoryRule
+
+category_null = Category("null", None, set())
+
+category_cat1 = Category(
+    "cat#1",
+    None,
+    {CategoryRule(None, None, "desc#1", None, None, None, Decimal(0), "cat#1")},
+)
diff --git a/tests/test_transform.py b/tests/test_transform.py
new file mode 100644
index 0000000..ead5ed1
--- /dev/null
+++ b/tests/test_transform.py
@@ -0,0 +1,52 @@
+from datetime import date
+from decimal import Decimal
+
+import mocks.categories as mock
+
+from pfbudget.db.model import (
+    Bank,
+    BankTransaction,
+    CategorySelector,
+    Selector_T,
+    TransactionCategory,
+)
+from pfbudget.transform.categorizer import Categorizer
+
+
+class TestTransform:
+    def test_nullify(self):
+        transactions = [
+            BankTransaction(
+                date(2023, 1, 1), "", Decimal("-500"), Bank("Bank#1", "", "")
+            ),
+            BankTransaction(
+                date(2023, 1, 2), "", Decimal("500"), Bank("Bank#2", "", "")
+            ),
+        ]
+
+        for t in transactions:
+            assert not t.category
+
+        categorizer = Categorizer()
+        categorizer.rules(transactions, [mock.category_null], [])
+
+        for t in transactions:
+            assert t.category == TransactionCategory(
+                "null", CategorySelector(Selector_T.nullifier)
+            )
+
+    def test_categorize(self):
+        transactions = [
+            BankTransaction(date(2023, 1, 1), "desc#1", Decimal("-10"), "Bank#1")
+        ]
+
+        for t in transactions:
+            assert not t.category
+
+        categorizer = Categorizer()
+        categorizer.rules(transactions, [mock.category_cat1], [])
+
+        for t in transactions:
+            assert t.category == TransactionCategory(
+                "cat#1", CategorySelector(Selector_T.rules)
+            )