Add tests for FormBuilderRangeSlider

Author: nrallakis

test/form_builder_range_slider_test.dart

@@ -0,0 +1,62 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_form_builder/flutter_form_builder.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'form_builder_tester.dart';
+
+void main() {
+  group('FormBuilderRangeSlider --', () {
+    testWidgets('basic', (WidgetTester tester) async {
+      const widgetName = 'formBuilderRangeSlider';
+      final testWidget = FormBuilderRangeSlider(
+        name: widgetName,
+        min: 10.0,
+        max: 20.0,
+      );
+      await tester.pumpWidget(buildTestableFieldWidget(testWidget));
+
+      expect(formSave(), isTrue);
+      expect(formValue<RangeValues?>(widgetName),
+          equals(const RangeValues(10.0, 10.0)));
+
+      // Inspired by https://github.com/flutter/flutter/blob/master/packages/flutter/test/material/range_slider_test.dart
+      // Tap at the center of the slider.
+      final Offset topLeft =
+          tester.getTopLeft(find.byType(RangeSlider)).translate(24, 0);
+      final Offset bottomRight =
+          tester.getBottomRight(find.byType(RangeSlider)).translate(-24, 0);
+      final Offset rightTarget = topLeft + (bottomRight - topLeft) * 0.5;
+      await tester.tapAt(rightTarget);
+
+      expect(formSave(), isTrue);
+      expect(formValue<RangeValues>(widgetName), const RangeValues(10.0, 15.0));
+    });
+
+    testWidgets('initial value', (WidgetTester tester) async {
+      const widgetName = 'formBuilderRangeSlider';
+      final testWidget = FormBuilderRangeSlider(
+        name: widgetName,
+        min: 10.0,
+        max: 20.0,
+        initialValue: const RangeValues(14.0, 18.0),
+      );
+      await tester.pumpWidget(buildTestableFieldWidget(testWidget));
+
+      expect(formSave(), isTrue);
+      expect(formValue<RangeValues?>(widgetName),
+          equals(const RangeValues(14.0, 18.0)));
+
+      // Inspired by https://github.com/flutter/flutter/blob/master/packages/flutter/test/material/range_slider_test.dart
+      // Tap a small offset after the start of the slider.
+      final Offset topLeft =
+          tester.getTopLeft(find.byType(RangeSlider)).translate(24, 0);
+      final Offset bottomRight =
+          tester.getBottomRight(find.byType(RangeSlider)).translate(-24, 0);
+      final Offset leftTarget = topLeft + (bottomRight - topLeft) * 0.1;
+      await tester.tapAt(leftTarget);
+
+      expect(formSave(), isTrue);
+      expect(formValue<RangeValues>(widgetName), const RangeValues(11.0, 18.0));
+    });
+  });
+}