optimize transpose service

src/app/modules/songs/services/transpose.service.spec.ts

@@ -1,6 +1,8 @@
 import {TestBed} from '@angular/core/testing';
 
 import {TransposeService} from './transpose.service';
+import {LineType} from './line-type';
+import {Line} from './line';
 
 describe('TransposeService', () => {
   let service: TransposeService;
@@ -12,7 +14,7 @@ describe('TransposeService', () => {
 
   it('should create map upwards', () => {
     const distance = service.getDistance('D', 'G');
-    const map = service.getMap('D', distance);
+    const map = service.getMap('D', 'G', distance);
 
     if (map) {
       void expect(map['D']).toBe('G');
@@ -21,10 +23,71 @@ describe('TransposeService', () => {
 
   it('should create map downwards', () => {
     const distance = service.getDistance('G', 'D');
-    const map = service.getMap('G', distance);
+    const map = service.getMap('G', 'D', distance);
 
     if (map) {
       void expect(map['G']).toBe('D');
     }
   });
+
+  it('should transpose enharmonic targets by semitone distance', () => {
+    const distance = service.getDistance('C', 'Db');
+    const map = service.getMap('C', 'Db', distance);
+
+    expect(distance).toBe(1);
+    expect(map?.['C']).toBe('Db');
+    expect(map?.['G']).toBe('Ab');
+  });
+
+  it('should keep german B/H notation consistent', () => {
+    const distance = service.getDistance('H', 'C');
+    const map = service.getMap('H', 'C', distance);
+
+    expect(distance).toBe(1);
+    expect(map?.['H']).toBe('C');
+    expect(map?.['B']).toBe('C#');
+  });
+
+  it('should render unknown chords as X', () => {
+    const line: Line = {
+      type: LineType.chord,
+      text: '',
+      chords: [
+        {chord: 'Q', add: 'sus4', slashChord: null, position: 0, length: 1},
+      ],
+    };
+
+    const rendered = service.renderChords(line);
+
+    expect(rendered.text).toBe('Xsus4');
+  });
+
+  it('should render unknown slash chords as X', () => {
+    const line: Line = {
+      type: LineType.chord,
+      text: '',
+      chords: [
+        {chord: 'C', add: null, slashChord: 'Q', position: 0, length: 1},
+      ],
+    };
+
+    const rendered = service.renderChords(line);
+
+    expect(rendered.text).toBe('C/X');
+  });
+
+  it('should transpose lines with long chord positions without truncating', () => {
+    const line: Line = {
+      type: LineType.chord,
+      text: '',
+      chords: [
+        {chord: 'C', add: null, slashChord: null, position: 120, length: 1},
+      ],
+    };
+
+    const rendered = service.renderChords(line);
+
+    expect(rendered.text.length).toBe(121);
+    expect(rendered.text.endsWith('C')).toBeTrue();
+  });
 });