test(enharmonic_interval): add test cases for transposeBy (#34)

* fix(enharmonic_interval): use `chromaticModExcludeZero` * test(enharmonic_interval): add test cases for `transposeBy`
albertms10 · Apr 9, 2023 · 5db17d8 · 5db17d8
1 parent 8bcbfd4
commit 5db17d8
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Showing 2 changed files with 27 additions and 7 deletions.
diff --git a/lib/src/interval/enharmonic_interval.dart b/lib/src/interval/enharmonic_interval.dart
@@ -63,14 +63,10 @@ class EnharmonicInterval extends Enharmonic<Interval> {
   ///
   /// Example:
   /// ```dart
-  /// EnharmonicInterval({
-  ///   const Interval(Intervals.sixth, Qualities.major),
-  /// }).transposeBy(-3)
-  ///   == EnharmonicInterval({
-  ///     const Interval(Intervals.fourth, Qualities.perfect),
-  ///   })
+  /// EnharmonicInterval(6).transposeBy(-3) == EnharmonicInterval(3)
+  /// EnharmonicInterval(8).transposeBy(6) == EnharmonicInterval(2)
   /// ```
   @override
   EnharmonicInterval transposeBy(int semitones) =>
-      EnharmonicInterval(this.semitones + semitones);
+      EnharmonicInterval((this.semitones + semitones).chromaticModExcludeZero);
 }
diff --git a/test/src/interval/enharmonic_interval_test.dart b/test/src/interval/enharmonic_interval_test.dart
@@ -22,6 +22,30 @@ void main() {
       });
     });
 
+    group('.transposeBy()', () {
+      test(
+        'should return the transposed EnharmonicInterval by semitones',
+        () {
+          expect(
+            const EnharmonicInterval(1).transposeBy(2),
+            const EnharmonicInterval(3),
+          );
+          expect(
+            const EnharmonicInterval(6).transposeBy(-3),
+            const EnharmonicInterval(3),
+          );
+          expect(
+            const EnharmonicInterval(8).transposeBy(6),
+            const EnharmonicInterval(2),
+          );
+          expect(
+            const EnharmonicInterval(4).transposeBy(-6),
+            const EnharmonicInterval(10),
+          );
+        },
+      );
+    });
+
     group('.hashCode', () {
       test('should ignore equal EnharmonicInterval instances in a Set', () {
         final collection = {