increase test coverage

extend test coverage

tests/e2e/unit/svgcore-touch.spec.js

@@ -0,0 +1,83 @@
+import { test, expect } from '../fixtures.js'
+
+test.describe('touch event adapter', () => {
+  test.beforeEach(async ({ page }) => {
+    await page.goto('/tests/unit-harness.html')
+    await page.waitForFunction(() => Boolean(window.svgHarness))
+  })
+
+  test('translates single touch events into mouse events', async ({ page }) => {
+    const result = await page.evaluate(() => {
+      const { touch } = window.svgHarness
+      const target = document.createElement('div')
+      document.body.append(target)
+
+      const received = []
+      target.addEventListener('mousedown', (ev) => {
+        received.push({
+          type: ev.type,
+          clientX: ev.clientX,
+          clientY: ev.clientY,
+          screenX: ev.screenX,
+          screenY: ev.screenY
+        })
+      })
+
+      const svgroot = {
+        listeners: {},
+        addEventListener (type, handler) { this.listeners[type] = handler },
+        dispatchEvent (ev) { this.listeners[ev.type]?.(ev) }
+      }
+
+      touch.init({ svgroot })
+      const ev = new TouchEvent('touchstart', {
+        changedTouches: [
+          new Touch({
+            identifier: 1,
+            target,
+            clientX: 12,
+            clientY: 34,
+            screenX: 56,
+            screenY: 78
+          })
+        ]
+      })
+      svgroot.dispatchEvent(ev)
+      return received[0]
+    })
+
+    expect(result.type).toBe('mousedown')
+    expect(result.clientX).toBe(12)
+    expect(result.clientY).toBe(34)
+    expect(result.screenX).toBe(56)
+    expect(result.screenY).toBe(78)
+  })
+
+  test('ignores multi-touch gestures when forwarding', async ({ page }) => {
+    const count = await page.evaluate(() => {
+      const { touch } = window.svgHarness
+      const target = document.createElement('div')
+      document.body.append(target)
+      let mouseEvents = 0
+      target.addEventListener('mousedown', () => { mouseEvents++ })
+
+      const svgroot = {
+        listeners: {},
+        addEventListener (type, handler) { this.listeners[type] = handler },
+        dispatchEvent (ev) { this.listeners[ev.type]?.(ev) }
+      }
+
+      touch.init({ svgroot })
+      const ev = new TouchEvent('touchstart', {
+        changedTouches: [
+          new Touch({ identifier: 1, target, clientX: 1, clientY: 2, screenX: 3, screenY: 4 }),
+          new Touch({ identifier: 2, target, clientX: 5, clientY: 6, screenX: 7, screenY: 8 })
+        ]
+      })
+      svgroot.dispatchEvent(ev)
+      return mouseEvents
+    })
+
+    expect(count).toBe(0)
+  })
+})