add Table._meta.email_columns (#610)

piccolo/table.py

@@ -11,6 +11,7 @@
     JSON,
     JSONB,
     Array,
+    Email,
     ForeignKey,
     Secret,
     Serial,
@@ -69,6 +70,7 @@ class TableMeta:
     columns: t.List[Column] = field(default_factory=list)
     default_columns: t.List[Column] = field(default_factory=list)
     non_default_columns: t.List[Column] = field(default_factory=list)
+    email_columns: t.List[Email] = field(default_factory=list)
     foreign_key_columns: t.List[ForeignKey] = field(default_factory=list)
     primary_key: Column = field(default_factory=Column)
     json_columns: t.List[t.Union[JSON, JSONB]] = field(default_factory=list)
@@ -216,6 +218,7 @@ def __init_subclass__(
         foreign_key_columns: t.List[ForeignKey] = []
         secret_columns: t.List[Secret] = []
         json_columns: t.List[t.Union[JSON, JSONB]] = []
+        email_columns: t.List[Email] = []
         primary_key: t.Optional[Column] = None
         m2m_relationships: t.List[M2M] = []
 
@@ -249,6 +252,9 @@ def __init_subclass__(
                 if isinstance(column, Array):
                     column.base_column._meta._table = cls
 
+                if isinstance(column, Email):
+                    email_columns.append(column)
+
                 if isinstance(column, Secret):
                     secret_columns.append(column)
 
@@ -275,6 +281,7 @@ def __init_subclass__(
             columns=columns,
             default_columns=default_columns,
             non_default_columns=non_default_columns,
+            email_columns=email_columns,
             primary_key=primary_key,
             foreign_key_columns=foreign_key_columns,
             json_columns=json_columns,

tests/table/test_metaclass.py

@@ -1,7 +1,13 @@
 from unittest import TestCase
 
 from piccolo.columns import Secret
-from piccolo.columns.column_types import JSON, JSONB, ForeignKey
+from piccolo.columns.column_types import (
+    JSON,
+    JSONB,
+    Email,
+    ForeignKey,
+    Varchar,
+)
 from piccolo.table import Table
 from tests.example_apps.music.tables import Band
 
@@ -76,6 +82,17 @@ class MyTable(Table):
             MyTable._meta.json_columns, [MyTable.column_a, MyTable.column_b]
         )
 
+    def test_email_columns(self):
+        """
+        Make sure ``TableMeta.email_columns`` are setup correctly.
+        """
+
+        class MyTable(Table):
+            column_a = Email()
+            column_b = Varchar()
+
+        self.assertEqual(MyTable._meta.email_columns, [MyTable.column_a])
+
     def test_id_column(self):
         """
         Makes sure an id column is added.