Add comprehensive tests for core functionality

src/tests/connectionCalculator.test.js

@@ -0,0 +1,128 @@
+import {
+  calculateCurve,
+  updateConnection
+} from '../connectionCalculator';
+
+describe('connectionCalculator', () => {
+  describe('calculateCurve', () => {
+    test('generates correct curve for horizontal connection', () => {
+      const from = { x: 0, y: 100 };
+      const to = { x: 300, y: 100 };
+
+      const curve = calculateCurve(from, to);
+
+      expect(curve).toContain('M0,100');
+      expect(curve).toContain('300,100');
+      expect(typeof curve).toBe('string');
+      expect(curve.length).toBeGreaterThan(0);
+    });
+
+    test('generates correct curve for vertical connection', () => {
+      const from = { x: 100, y: 0 };
+      const to = { x: 100, y: 300 };
+
+      const curve = calculateCurve(from, to);
+
+      expect(curve).toContain('M100,0');
+      expect(curve).toContain('100,300');
+    });
+
+    test('handles negative coordinates', () => {
+      const from = { x: -50, y: -100 };
+      const to = { x: 50, y: 100 };
+
+      const curve = calculateCurve(from, to);
+
+      expect(curve).toContain('M-50,-100');
+      expect(curve).toContain('50,100');
+    });
+
+    test('handles zero-length connection', () => {
+      const from = { x: 100, y: 100 };
+      const to = { x: 100, y: 100 };
+
+      const curve = calculateCurve(from, to);
+
+      expect(typeof curve).toBe('string');
+    });
+
+    test('creates proper bezier curve with control points', () => {
+      const from = { x: 0, y: 0 };
+      const to = { x: 300, y: 200 };
+
+      const curve = calculateCurve(from, to);
+
+      // Should contain the start point, control points, and end point
+      expect(curve).toContain('M0,0');
+      expect(curve).toContain('300,200');
+      // Should create a bezier curve (contains 'C' for cubic bezier)
+      expect(curve).toContain('C');
+    });
+
+    test('handles curve with different horizontal distances', () => {
+      const testCases = [
+        { from: { x: 0, y: 0 }, to: { x: 100, y: 0 } },
+        { from: { x: 0, y: 0 }, to: { x: 500, y: 0 } },
+        { from: { x: 0, y: 0 }, to: { x: 50, y: 0 } }
+      ];
+
+      testCases.forEach(({ from, to }) => {
+        const curve = calculateCurve(from, to);
+        expect(typeof curve).toBe('string');
+        expect(curve.length).toBeGreaterThan(0);
+        expect(curve).toContain(`M${from.x},${from.y}`);
+        expect(curve).toContain(`${to.x},${to.y}`);
+      });
+    });
+  });
+
+  describe('updateConnection', () => {
+    test('updates connection path attribute', () => {
+      const mockLine = {
+        setAttribute: jest.fn()
+      };
+      const from = { x: 0, y: 0 };
+      const to = { x: 100, y: 100 };
+
+      updateConnection({ line: mockLine, from, to });
+
+      expect(mockLine.setAttribute).toHaveBeenCalledWith('d', expect.any(String));
+
+      // Verify the path string is a valid curve
+      const pathString = mockLine.setAttribute.mock.calls[0][1];
+      expect(pathString).toContain('M0,0');
+      expect(pathString).toContain('100,100');
+    });
+
+    test('handles multiple update calls', () => {
+      const mockLine = {
+        setAttribute: jest.fn()
+      };
+
+      // First update
+      updateConnection({ 
+        line: mockLine, 
+        from: { x: 0, y: 0 }, 
+        to: { x: 100, y: 100 } 
+      });
+
+      // Second update
+      updateConnection({ 
+        line: mockLine, 
+        from: { x: 50, y: 50 }, 
+        to: { x: 150, y: 150 } 
+      });
+
+      expect(mockLine.setAttribute).toHaveBeenCalledTimes(2);
+
+      // Check both calls had valid path strings
+      const firstCall = mockLine.setAttribute.mock.calls[0][1];
+      const secondCall = mockLine.setAttribute.mock.calls[1][1];
+
+      expect(firstCall).toContain('M0,0');
+      expect(firstCall).toContain('100,100');
+      expect(secondCall).toContain('M50,50');
+      expect(secondCall).toContain('150,150');
+    });
+  });
+});