Added scale unit tests provided by @nesquikm

test/max_scale_test.dart

@@ -0,0 +1,48 @@
+import 'package:money2/money2.dart';
+import 'package:test/test.dart';
+
+void main() {
+  const maxScale = 100;
+  const maxInts = 100;
+
+  test('scale 0-$maxScale test', () {
+    for (var scale = 0; scale <= maxScale; scale++) {
+      final str = scale == 0 ? '1' : '1.${'0' * (scale - 1)}1';
+      final fmt = scale == 0 ? 'S#' : '#.${'#' * scale}';
+      expect(Fixed.parse(str, scale: scale).format(fmt), str,
+          reason: 'Failed with $scale scale');
+    }
+  });
+
+  test('integers 0-$maxInts test', () {
+    for (var ints = 0; ints <= maxInts; ints++) {
+      final str = ints == 0 ? '0' : '9' * ints;
+      const fmt = '#';
+      expect(Fixed.parse(str, scale: 0).format(fmt), str,
+          reason: 'Failed with $ints ints');
+    }
+  });
+
+  test('scale 0-$maxScale and integers 0-$maxInts test', () {
+    for (var scale = 0; scale <= maxScale; scale++) {
+      for (var ints = 0; ints <= maxInts; ints++) {
+        final intsStr = ints == 0 ? '0' : '9' * ints;
+        final str = scale == 0 ? intsStr : '$intsStr.${'0' * (scale - 1)}1';
+
+        // Fixed doesn't like leading zeroes!
+        final expectIntsStr = (ints == 0 && scale == 0)
+            ? '0'
+            : ints == 0
+                ? ''
+                : '9' * ints;
+        final expectStr =
+            scale == 0 ? expectIntsStr : '$expectIntsStr.${'0' * (scale - 1)}1';
+
+        final fmt = scale == 0 ? '#' : '#.${'#' * scale}';
+
+        expect(Fixed.parse(str, scale: scale).format(fmt), expectStr,
+            reason: 'Failed with $scale scale, $ints ints');
+      }
+    }
+  });
+}