Provide comparable expressions for pg time values

extras/drift_postgres/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 1.2.0
+
+- Drift's comparable expression operators are now available for expressions
+  using postgres-specific `date` or `timestamp` types.
+
 ## 1.1.0
 
 - Add `PgTypes.timestampWithTimezone`.

extras/drift_postgres/lib/drift_postgres.dart

@@ -80,7 +80,7 @@ final class PgTypes {
 ///
 /// We can't use [DateTime] directly because drift expects to store them as
 /// unix timestamp or text.
-final class PgDateTime implements PgTimeValue {
+final class PgDateTime implements PgTimeValue, Comparable<PgDateTime> {
   final DateTime dateTime;
 
   PgDateTime(this.dateTime);
@@ -98,11 +98,16 @@ final class PgDateTime implements PgTimeValue {
 
   @override
   String toString() => dateTime.toString();
+
+  @override
+  int compareTo(PgDateTime other) {
+    return dateTime.compareTo(other.dateTime);
+  }
 }
 
 /// A wrapper for the Postgres `date` type, which stores dates (year, month,
 /// days).
-final class PgDate implements PgTimeValue {
+final class PgDate implements PgTimeValue, Comparable<PgDate> {
   final int year, month, day;
   final DateTime _dateTime;
 
@@ -134,6 +139,11 @@ final class PgDate implements PgTimeValue {
   DateTime toDateTime() {
     return _dateTime;
   }
+
+  @override
+  int compareTo(PgDate other) {
+    return _dateTime.compareTo(other._dateTime);
+  }
 }
 
 /// Calls the `gen_random_uuid` function in postgres.

extras/drift_postgres/pubspec.yaml

@@ -1,6 +1,6 @@
 name: drift_postgres
 description: Postgres implementation and APIs for the drift database package.
-version: 1.1.0
+version: 1.2.0-dev
 repository: https://github.com/simolus3/drift
 homepage: https://drift.simonbinder.eu/docs/platforms/postgres/
 issue_tracker: https://github.com/simolus3/drift/issues

extras/drift_postgres/test/types_test.dart

@@ -20,22 +20,22 @@ void main() {
     await executor.clearDatabaseAndClose(database);
   });
 
+  Future<T> eval<T extends Object>(Expression<T> expression) async {
+    final query = database.selectOnly(database.users)..addColumns([expression]);
+    final row = await query.getSingle();
+    return row.read(expression)!;
+  }
+
   group('custom types pass through', () {
     void testWith<T extends Object>(CustomSqlType<T> type, T value) {
       test('with variable', () async {
         final variable = Variable(value, type);
-        final query = database.selectOnly(database.users)
-          ..addColumns([variable]);
-        final row = await query.getSingle();
-        expect(row.read(variable), value);
+        expect(await eval(variable), value);
       });
 
       test('with constant', () async {
         final constant = Constant(value, type);
-        final query = database.selectOnly(database.users)
-          ..addColumns([constant]);
-        final row = await query.getSingle();
-        expect(row.read(constant), value);
+        expect(await eval(constant), value);
       });
     }
 
@@ -59,4 +59,27 @@ void main() {
           PgDateTime(DateTime.utc(1996, 7, 8, 10, 0, 0))),
     );
   });
+
+  test('compare datetimes', () async {
+    final time = DateTime.now();
+    final before = Variable(
+        PgDateTime(time.subtract(const Duration(minutes: 10))),
+        PgTypes.timestampNoTimezone);
+    final now = Variable(PgDateTime(time), PgTypes.timestampNoTimezone);
+    final after = Variable(PgDateTime(time.add(const Duration(days: 2))),
+        PgTypes.timestampNoTimezone);
+
+    expect(await eval(before.isSmallerOrEqual(after)), isTrue);
+    expect(await eval(now.isBetween(before, after)), isTrue);
+  });
+
+  test('compare dates', () async {
+    final moonLanding = PgDate(year: 1969, month: 7, day: 20);
+    final berlinWallFell = PgDate(year: 1989, month: 11, day: 9);
+
+    expect(
+        await eval(Variable(berlinWallFell, PgTypes.date)
+            .isBiggerOrEqualValue(moonLanding)),
+        isTrue);
+  });
 }