toStringSignedAsFixed tests

lib/screens/metering/components/camera_container/components/camera_controls/components/exposure_offset_slider/widget_slider_exposure_offset.dart

@@ -72,7 +72,7 @@ class _Ruler extends StatelessWidget {
             children: [
               if (showValue)
                 Text(
-                  (index + min).toStringSigned(),
+                  (index + min).toStringSignedAsFixed(0),
                   style: Theme.of(context).textTheme.bodyLarge,
                 ),
               const SizedBox(width: Dimens.grid8),

lib/utils/to_string_signed.dart

@@ -1,13 +1,4 @@
-extension SignedString on num {
+/// Returns value in form -1 or + 1. The only exception - 0.
-  String toStringSigned() {
-    if (this > 0) {
-      return "+${toString()}";
-    } else {
-      return toString();
-    }
-  }
-}
-
 extension SignedStringDouble on double {
   String toStringSignedAsFixed(int fractionDigits) {
     if (this > 0) {

test/utils/to_string_signed_test.dart

@@ -0,0 +1,16 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:lightmeter/utils/to_string_signed.dart';
+
+void main() {
+  test('toStringSignedAsFixed(0)', () {
+    expect(1.5.toStringSignedAsFixed(0), '+2');
+    expect((-1.5).toStringSignedAsFixed(0), '-2');
+    expect(0.0.toStringSignedAsFixed(0), '0');
+  });
+
+  test('toStringSignedAsFixed(1)', () {
+    expect(1.5.toStringSignedAsFixed(1), '+1.5');
+    expect((-1.5).toStringSignedAsFixed(1), '-1.5');
+    expect(0.0.toStringSignedAsFixed(1), '0.0');
+  });
+}