Added tests for Per Link Curve Styling

packages/mermaid/src/diagrams/flowchart/flowDb.spec.ts

@@ -125,4 +125,43 @@ describe('flow db getData', () => {
     const { edges } = flowDb.getData();
     expect(edges[0].curve).toBe('basis');
   });
+
+  it('should support modifying interpolate using edge id syntax', () => {
+    flowDb.addVertex('A', { text: 'A', type: 'text' }, undefined, [], [], '', {}, undefined);
+    flowDb.addVertex('B', { text: 'B', type: 'text' }, undefined, [], [], '', {}, undefined);
+    flowDb.addVertex('C', { text: 'C', type: 'text' }, undefined, [], [], '', {}, undefined);
+    flowDb.addVertex('D', { text: 'D', type: 'text' }, undefined, [], [], '', {}, undefined);
+    flowDb.addLink(['A'], ['B'], {});
+    flowDb.addLink(['A'], ['C'], { id: 'e2' });
+    flowDb.addLink(['B'], ['D'], { id: 'e3' });
+    flowDb.addLink(['C'], ['D'], {});
+    flowDb.updateLinkInterpolate(['default'], 'stepBefore');
+    flowDb.updateLinkInterpolate([0], 'basis');
+    flowDb.addVertex(
+      'e2',
+      { text: 'Shouldnt be used', type: 'text' },
+      undefined,
+      [],
+      [],
+      '',
+      {},
+      ' curve: monotoneX '
+    );
+    flowDb.addVertex(
+      'e3',
+      { text: 'Shouldnt be used', type: 'text' },
+      undefined,
+      [],
+      [],
+      '',
+      {},
+      ' curve: catmullRom '
+    );
+
+    const { edges } = flowDb.getData();
+    expect(edges[0].curve).toBe('basis');
+    expect(edges[1].curve).toBe('monotoneX');
+    expect(edges[2].curve).toBe('catmullRom');
+    expect(edges[3].curve).toBe('stepBefore');
+  });
 });

packages/mermaid/src/diagrams/flowchart/parser/flow-lines.spec.js

@@ -37,6 +37,59 @@ describe('[Lines] when parsing', () => {
     expect(edges[1].interpolate).toBe('cardinal');
   });
 
+  it('should handle edge curve properties using edge ID', function () {
+    const res = flow.parser.parse(
+      'graph TD\n' +
+        'A e1@-->B\n' +
+        'A uniqueName@-->C\n' +
+        'e1@{curve: basis}\n' +
+        'uniqueName@{curve: cardinal}'
+    );
+
+    const vert = flow.parser.yy.getVertices();
+    const edges = flow.parser.yy.getEdges();
+
+    expect(edges[0].interpolate).toBe('basis');
+    expect(edges[1].interpolate).toBe('cardinal');
+  });
+
+  it('should handle edge curve properties using edge ID but without overriding default', function () {
+    const res = flow.parser.parse(
+      'graph TD\n' +
+        'A e1@-->B\n' +
+        'A-->C\n' +
+        'linkStyle default interpolate linear\n' +
+        'e1@{curve: stepAfter}'
+    );
+
+    const vert = flow.parser.yy.getVertices();
+    const edges = flow.parser.yy.getEdges();
+
+    expect(edges[0].interpolate).toBe('stepAfter');
+    expect(edges.defaultInterpolate).toBe('linear');
+  });
+
+  it('should handle edge curve properties using edge ID mixed with line interpolation', function () {
+    const res = flow.parser.parse(
+      'graph TD\n' +
+        'A e1@-->B-->D\n' +
+        'A-->C e4@-->D-->E\n' +
+        'linkStyle default interpolate linear\n' +
+        'linkStyle 1 interpolate basis\n' +
+        'e1@{curve: monotoneX}\n' +
+        'e4@{curve: stepBefore}'
+    );
+
+    const vert = flow.parser.yy.getVertices();
+    const edges = flow.parser.yy.getEdges();
+
+    expect(edges[0].interpolate).toBe('monotoneX');
+    expect(edges[1].interpolate).toBe('basis');
+    expect(edges.defaultInterpolate).toBe('linear');
+    expect(edges[3].interpolate).toBe('stepBefore');
+    expect(edges.defaultInterpolate).toBe('linear');
+  });
+
   it('should handle line interpolation multi-numbered definitions', function () {
     const res = flow.parser.parse(
       'graph TD\n' + 'A-->B\n' + 'A-->C\n' + 'linkStyle 0,1 interpolate basis'